Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Tim on December 21, 2016, 08:53:00 am
Title: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 21, 2016, 08:53:00 am
In designing the next generation solar / lithium electrical system for my 1997 U270, I have the following questions:
1. 220VAC WIRING How does Foretravel split the 50Amp 220V shore power? The schematics do not show it being split throughout the house electrical system. The generator is 120VAC. What is the use of extra 120VAC leg of the 220VAC shore power?
2. 48VDC BATTERIES Any reason why a 48VDC to 12VDC converter wouldn't work to power house loads like the referigerator, heaters and lights?
3. TAX REFUND Any reason why I couldn't take the 30% tax refund for purchasing 1200Watts of solar panels, 7KWH of lithium batteries, 48V solar MPPT charger, 48VDC to 12VDC converter and all associated wire, breakers and relays?
4. MOTIVATION Am I crazy because this is a lot of work that I will do myself? Will it make the coach worth more? Will it save money in the long-run over lead batteries? Being an electrical engineer, I look for ways to improve our boondocking capability and reduce annoying generator noise. Some campgrounds in Big Bend National Park prohibit all generators.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on December 21, 2016, 09:06:01 am
The electrical stuff is over my head, but this post (link below) may help you answer your question on the tax credit:
RV Solar Tax Credit (update) (http://www.foreforums.com/index.php?topic=27428.msg224513#msg224513)
The way it was explained to me, you can include any costs associated with making your residence (coach) ready to accept the solar installation. For instance, if a person was installing solar panels on the roof of a house, and the roof had to be "strengthened" to accept the added weight of the panels, then the cost of the roof reconstruction work could be included in the amount claimed on the credit.
I am not a tax attorney. If you have any questions about what can or cannot be claimed, I recommend consulting a tax expert.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Michelle on December 21, 2016, 09:15:29 am
1. 220VAC WIRING How does Foretravel split the 50Amp 220V shore power? The schematics do not show it being split throughout the house electrical system.
It should. There should be a page showing the main breaker box with Leg 1 and Leg 2.
I am not a tax attorney. If you have any questions about what can or cannot be claimed, I recommend consulting a tax expert.
^^^ What Chuck said. Your accountant/tax person is the only one who can accurately answer this for your situation. :) ^^^
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: craneman on December 21, 2016, 10:47:35 am
I thought the generator was 220 volt. Do different coaches have different configurations?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 21, 2016, 10:55:05 am
I believe all coaches are 220 volt output, but do not have a dedicated 220 circuit, only using both 120 to neutral legs. You will also need a dedicated 48 vdc to 120 vac inverter to run your regular 110v loads. It may make your coach worth more, but only expect about a 10% return on any upgrades you put in your coach if you sell it.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 21, 2016, 11:02:53 am
The data plate on my Isuzu IDL 8000 generator says "115VAC" period. In a way, that makes it simple, but I guess Foretravel decided that if you are only plugged into 30Amp 115VAC shore power, you had better be able to run the whole rig. The question remains: what is done with the other 115VAC leg?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Jim Frerichs on December 21, 2016, 11:08:50 am
I was told both legsare connected together at the generator. My Power Tech is a 120 volt generator. There are special instruction available to convert it to 220 volt output ...though you better know what you are doing to be sucessful.
Jim
2002 U320
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 21, 2016, 11:14:10 am
Generator Diagram to change 110vac to 240vac (http://beamalarm.com/Documents/powertech_generator_diagram_to_change_110vac_to_240vac.html)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 21, 2016, 11:37:55 am
While I'm no expert on generators, I believe both 110 volt legs go to the panel(s) powering one side of each bus therefore just like your home electric. It helps keep the load balanced. You can as I understand it make some minor changes in the generator to make I a true 220.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Pierce & Gaylie Stewart on December 21, 2016, 11:42:04 am
Tim,
Don't know if it will make the coach worth more. I put 1140 watts on the roof for the same reason, to get rid of the generator noise. I have not used the generator in years. I hate the noise, smell and vibration. At any kind of altitude, the generator really smells. Many National Parks mix tents with RV. I have had furious tent residents pound on my door to shut it off. Many NP visitors come from Europe where they don't use generators on RVs so don't understand why we allow them.
Don't think it's practical to expect 1200 watts on the roof to provide enough power for the heating, cooking, etc. When do you need heat the most? In winter with low sun angles. Plus, they won't run AC units if you dry camp in summer. You are not going to get anywhere near 1200 watts in a real world especially in winter. You would have to tilt the panels and I consider that too risky unless you motorized them. Parking in full sun is also iffy in many places. Stormy weather cuts the watts down, way down. Propane for heating, cooking and the fridge is a good compromise. Our 36' U300 with the walk though bath is one of the only Foretravels where you can mount four very large 300 watt panels without a conflict with AC, vents, etc. Otherwise, you have to utilize more smaller panels to get the same output. Makes it far more complex to tilt.
The roof or structure will not need reinforcement no matter how many panels you put up there.
With our panels, we bring about 70 volts down to a Midnite Classic 150 MPPT controller and then into 6 solar AGMs. They work great after almost 8 years for 40" TV, computer, lighting, latte maker, etc. At Quartzsite, in the dead of winter, we get about 600 watts. Enough to bring the batteries up by 10:30. I did it all myself after spending a lot of hours coming up to speed on all the dozens of little details. Commercial companies will never be able to match what a well informed RV owner can do. Looking around, I was able to get the highest quality possible components for less than $2000 plus the batteries. I got an unusual deal on the batteries so didn't include them in the cost. They came out of the back of a truck but they didn't fall out. :D
We just got back from a coast to coast and back trip. We mixed campgrounds with parking lots and in a month, never even thought about the generator. The trip in summer would mean either more campgrounds with power or generator use. In Mexico, we usually stay in campgrounds as they are located overlooking the ocean, have reasonable rates plus our stays are longer. It's nice to have the septic, water, hot clubhouse showers plus power for the ACs. The vendors with the fresh shrimp, tamales are an added perk.:-)
And yes, I took the tax deduction.
Pierce
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Ted & Karen on December 21, 2016, 12:18:14 pm
Tim- As an electrical engineer you know that it is almost impossible to make it perfect, but sounds like you are on to something you enjoy.
We live in our 2001 U270 full time and just this past January I had installed a simple solar system to reduce my generator use. The system has exceeded my original expectations and I am very pleased with the results.
I have 2 roof mounted 250 Watt, high efficiency 24 volt panels, running down to the MPPT controller which converts the voltage to 12 volts, then to my 2 8G8D batteries. This system works very well and I have the option but choose not to climb up and tilt the panels. We use propane for heat, cooking, refrigerator and a smaller inverter to charge cell phones, laptops, etc. I only turn on the big 3000 Watt inverter when we need it or want it to power tv, etc. We can go a long time without ever running the generator, unless we are going to do baking or something like that. In the spring time, we have gone 2.5 weeks strictly on solar.
I had my system installed out in Slab City in the desert of CA by Solar Mike for $1200. Happy with the price, happy with the work, happy with the results.
Figure out how you want to use your system and design it based on your usage. I don't expect this to be an investment for anyone but us as we plan on living in this coach another 10 plus years.
Keep us informed about your project. I am interested in how the Lithium batteries will work long term.
Merry Christmas
^.^d
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 21, 2016, 12:33:43 pm
Hey Ted, just had Mike at Slab City put 850 watts on the roof, works great.
X 2 on what Pierce said.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: George and Steph on December 21, 2016, 12:40:14 pm
Tim I will post some answers to your questions shortly. We have the same coach and I just added 900w solar, 3000 Multi inverter, 400 ah lithium, and CCGX panel. I went all Victron and glad I did. There were several work arounds required and my best guess is I am somewhere around 150 hours into the project, not counting the first month and a half learning electricity, and buttoning up today and tomorrow. I did not have previous electrical experience as you do but learned on the job and climbed and confessed to AM Solar when I got lost. I was their first DIY coach of this type. Made for a great learning experience for both parties and they have changed a number of things based on that learning curve.
My first home remodeling effort was the kitchen to the studs and this was a similar journey. My immortal beloved was a little less patient with that one.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Ted & Karen on December 21, 2016, 02:43:26 pm
Hey Bruce- glad it worked out for you. Mike knows his solar and is a unique person- a pleasure doing business with him.
^.^d ^.^d
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: rbark on December 21, 2016, 07:59:18 pm
Bruce, was the price at slab city a better price than AM solar would do?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 21, 2016, 09:16:43 pm
I plan on:
- Three 320W solar panels from eBay - 7KWH of Lithium. That's 16 130AH LIFEPO4 batteries running at 48 volts - 48 volt solar MPPT charger - 48 volt to 120VAC pure sine wave inverter / charger - 48 volt to 12VDC charger. - The 12VDC house voltage may come from a small 30AH LIFEPO4 pack, which will be maintained by the 48V main pack.
Just have to figure out how to handle the genny and shore power. Big job.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: DavidS on December 21, 2016, 09:20:57 pm
Where are you getting the lifepo4 at? And how much ? Are you buying as a kit or assembled ?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 21, 2016, 09:33:31 pm
- Three 320W solar panels from eBay - 7KWH of Lithium. That's 16 130AH LIFEPO4 batteries running at 48 volts - 48 volt solar MPPT charger - 48 volt to 120VAC pure sine wave inverter / charger - 48 volt to 12VDC charger. - The 12VDC house voltage may come from a small 30AH LIFEPO4 pack, which will be maintained by the 48V main pack.
Just have to figure out how to handle the genny and shore power. Big job.
Do not skimp on the solar, general rule 1 watt solar to 1 ah battery. Will over 2000 ah's go big. A couple of cloudy days will deplete even 2000 ah's if you are running enough equipment. A good mppt controller will charge as fast as the batteries will take it and then shut off, so no such thing as too much solar. I had a foretravel with 1200 watts solar and 900 ah batteries, and there were times when I wished for more solar. If you leave an inch or so between panels and roof, heat transfer will not be a problem.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 21, 2016, 09:33:49 pm
Rbark yes way less expensive than AM solar. 2300.00 tax inc with an outback Flex max 80 mppt controller.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: TheBrays on December 21, 2016, 10:03:28 pm
Just have to figure out how to handle the genny and shore power. Big job.
Tim, These are for my '96 295. The first one "110v ELECT RELAY SYSTEM" (A-2700.07), shows two 110v hot legs coming to Transfer switch #1 from either the Shore Power line or the Generator. Sheet 1 of 2, A-2700.03 shows what circuits (in my nominal coach) are assigned to which legs.
Note that either the inverter output or leg 2 from shore/gen feed the circuits delineated on A-2700-3 page 2/2). HTH
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 22, 2016, 10:36:07 pm
Thanks for the diagrams. Do you have a diagram for SWITCHING RELAY #1?
This switching relay must have the "intelligence" for two states:
1. 220VAC SHORE POWER (50AMP) Connect each of the two 110VAC legs to the MAIN CIRCUIT BREAKER BOX, Circuit #5 and 7
2. 120VAC SHORE POWER (30AMP) or GENERATOR POWER Connect the single 120VAC leg to both legs of the MAIN CIRCUIT BREAKER BOX, Circuit #5 and 7
What happens if the genny is running and shore power are connected at the same time? Smoke?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: KenKetch on December 22, 2016, 10:54:55 pm
Can anyone who has installed solar on their coach describe how they ran the cables from the roof to the basement? I want to install solar on my U320.
Ken
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: tothetrail on December 22, 2016, 11:08:28 pm
Can anyone who has installed solar on their coach describe how they ran the cables from the roof to the basement? I want to install solar on my U320.
I ran them down the fridge vent, down the corner of the fridge compartment, then through the floor of the fridge compartment, then down through the ceiling of the basement bay, then across the ceiling of the center of the basement bay, along the large wire run (under a fiberglass ceiling panel) and into the battery bay.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 22, 2016, 11:09:40 pm
Ken down through the vent for the fridge, behind the false back in the cabinet below the fridge.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 22, 2016, 11:10:22 pm
Can anyone who has installed solar on their coach describe how they ran the cables from the roof to the basement? I want to install solar on my U320.
Ken
Through the fridge vent on the roof, then drill on bottom of rear fridge compartment into the compartment below fridge, then to basement compartment and fwd to where your controller is.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: KenKetch on December 22, 2016, 11:11:43 pm
Thanks, that is the route that I thought I would have to use. Ken
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: TheBrays on December 23, 2016, 08:53:00 am
Thanks for the diagrams. Do you have a diagram for SWITCHING RELAY #1?
This switching relay must have the "intelligence" for two states:
1. 220VAC SHORE POWER (50AMP) 2. 120VAC SHORE POWER (30AMP) or GENERATOR POWER ... What happens if the genny is running and shore power are connected at the same time? Smoke?
Tim, I think there is a diagram inside the TS box.
The Beamalarm site has a section on Transfer switches. A subsection, What has AC Priority on Foretravel RV (http://www.beamalarm.com/Documents/what_has_ac_priority.html) , describes which switches were used in the various years. It also lists which input takes priority.
The desire to positively know the source (and to simplify the process) has prompted discussions on the Forum about replacing TS#1 with a robust manual switch .
You don't get smoke, at least I havn't yet :o
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on December 23, 2016, 10:10:40 am
The desire to positively know the source (and to simplify the process) has prompted discussions on the Forum about replacing TS#1 with a robust manual switch .
Agree this is one of the main selling points of a manual switch. However, it does require "operator input", so not everyone's cup of tea.
A manual switch will, on occasion, trip you up. Example: (Caution: long story, so if you are busy, skip it)
On our recent trip to MOT for service work. They were going to service our generator, so the morning of the appointment, I unhooked from shore power and fired up the generator to warm up the oil. I dutifully put our manual switch on "GEN" so the DW could finish getting breakfast, etc.
The shop calls, says they are ready for us. I drive over to the shop with generator running - VERY busy parking lot - I carefully maneuver the coach trying to avoid scraping corners with the "million dollar" coaches in the lot. Driver comes to pull our coach into the bay - I quickly shut down the generator and get out of his way. They position the coach in the bay, very kindly plug us in to 50 amp to keep our (residential) fridge cold, and get right to work.
Fast forward to the end of the day. After getting our coach back from MOT, we drive over to FOT to spend the night. After I hook up the shore power cord, I go inside to verify that my switch is set on "SHORE". Guess what? It is still set on the "GEN" position from early that morning. Consequently, the coach had been running on inverter all day, instead of sucking "free" power from the MOT 50 amp outlet. :facepalm:
No harm done, of course. Our batteries easily handled the light load, just as they are supposed to. But this illustrates my point: If you make the change to a manual transfer switch, it is not automatic. You actually have to think about what you are doing (power supply-wise). Just something to keep in mind when weighing the pros/cons.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: craneman on December 23, 2016, 11:57:27 am
Any thoughts on how to get wires to the basement when the refrigerator vent has been fiber glassed closed when residential refrigerator was installed?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on December 23, 2016, 12:12:13 pm
Any thoughts on how to get wires to the basement when the refrigerator vent has been fiber glassed closed when residential refrigerator was installed?
On our coach, we installed residential fridge before solar, so our fridge vent was gone (I covered with a sheet metal "patch").
Also before solar install, I removed the old manual crank-up satellite dish from the rear end of the roof. I covered the large dish mounting hole, and the smaller entry hole for the cable, with aluminum plates. The cable entry hole through the roof came in through the aft closet ceiling. After looking at possibilities, AM Solar decided to use the existing (small) hole in the roof for the solar cables. The (2) junction boxes for the 6 panels are located under one of the panels. The cables from the boxes enter through the hole in the roof, into the closet, run down the open framework in the corner of the closet, down through the floor, and back up into the space at the foot of the bed. That's where our controllers are mounted.
Our story, with photos, linked below. I'm not pimping for AM Solar - just offering their work as one more example of different ways to do it.
PV System, Installation, at AM Solar (http://www.foreforums.com/index.php?topic=26206.msg209349#msg209349)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: craneman on December 23, 2016, 01:11:50 pm
On our coach, we installed residential fridge before solar, so our fridge vent was gone (I covered with a sheet metal "patch").
Also before solar install, I removed the old manual crank-up satellite dish from the rear end of the roof. I covered the large dish mounting hole, and the smaller entry hole for the cable, with aluminum plates. The cable entry hole through the roof came in through the aft closet ceiling. After looking at possibilities, AM Solar decided to use the existing (small) hole in the roof for the solar cables. The (2) junction boxes for the 6 panels are located under one of the panels. The cables from the boxes enter through the hole in the roof, into the closet, run down the open framework in the corner of the closet, down through the floor, and back up into the space at the foot of the bed. That's where our controllers are mounted.
Our story, with photos, linked below. I'm not pimping for AM Solar - just offering their work as one more example of ways to do it.
PV System, Installation, at AM Solar (http://www.foreforums.com/index.php?topic=26206.msg209349#msg209349) [/quote Thanks for the link, good info. The '99 U320 roof is quite different but when the time comes I will figure something out.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on January 23, 2017, 07:33:59 am
Anyone know what the "Generator Starter" does on a 1997 U270 Foretravel?
It is shown on the attached schematic, circled in red.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Pamela & Mike on January 23, 2017, 07:47:07 am
Tim,
That is the device (starter motor) that turns over the power unit (engine) when you push the generator start button.
Pamela & Mike
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on January 23, 2017, 11:53:55 am
Ha ha, very funny Pamela and Mike. The starter is is on the bottom center of the diagram. Perhaps I should clarify my question:
Why would there be a wire connecting the Coach Battery to the "Generator Starter"?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Don & Tys on January 23, 2017, 12:04:52 pm
Since there is no dedicated start battery for the generator starter motor, there is a cable run from the breaker panel 90 amp D.C. Breaker located originally on the other side of the compartment wall adjacent to to the house battery tray. It is a pretty heavy gauge (2 or 4 gauge I think) red wire with labeled with the number you see on that diagram. At least that is how it was on our 99' U270... Don
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Pamela & Mike on January 23, 2017, 01:01:19 pm
Ha ha, very funny Pamela and Mike. The starter is is on the bottom center of the diagram. Perhaps I should clarify my question:
If you look the starter you are talking about is for your main engine. It is fed off the engine batteries not the coach batteries.
Like Don has mentioned if you follow the wire back from your red circle you will see it goes to your coach/house batteries. This is where your generator starter gets power from.
Pamela & Mike
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: George and Steph on January 23, 2017, 02:45:33 pm
We have the same coach and schematic. That wire goes to the coach batterys as shown. The number is prominently displayed as they did a good job of marking. I took it off the house battery's when we installed the lithium. I ran a 2/0 cable forward from engine bank and joined them at a switch. Your gen set wants 3-400 to kick I was worried about chassis ground and the gen set. I wanted to isolate them initially until our system was fully tested.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on January 23, 2017, 09:11:12 pm
Ah, now I get it! It's for the genny starter. Sorry for being dense.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 29, 2017, 07:27:07 am
Summary: Get more battery and solar power. See photo.
Details: The 48V lithium battery went dead, so I recommend getting even more solar (More than 1920 watts) and ESPECIALLY more battery capacity than 9 KWH. Read on for more details.
Even more details: It's 19 degrees F, just so you know where this is going. We spent the day and night heading to Florida. However, after unplugging from house 220VAC pedestal at 10 degrees F, we spent 14 hours driving in 10 to 22 degree weather. It was sunny, but the following led to the LVD (Low Voltage Discharge) of my all-powerful LiFePo4 battery:
- BTUs: Avoided water pipe freezing by turning on electric basement heaters. Drew up to 800 watts from the 48v battery. Driving in freezing temperatures causes a rapid decrease in basement temperature. The small stock Foretravel furnace ducts could not keep up with the utility bay's heat requirement because the cabin was being heated by the sun. It was 80 degrees in the cabin but 32 degrees in the basement. - Poor charging capaility in winter. Low sun angle and a short solar day produced only 68AH (about 3.4KWh) from the 1.9KW solar panels. This power was used for the basement heaters. - Genny to the rescue. At 6AM, the inverter shut down. I awoke and started the genny. At 19 degrees F, she wasn't happy but started on the first try. Running the engine pre-heater (1KW) will help the main engine start. The lithium battery could not handle several hours of this load.
BOTTOM LINE - Double the pack capacity (yes, a ludicrous 18KWH pack. Used Chevy Volt or Nissan Leaf packs are selling for $3,000 on eBay. These are 18KWH to 24KWH respectively. I spent $4,000 on this LiFePo4 9KWH pack. - Enlarge furnace ducts and add a temperature-controlled duct damper and/or fan from the main cabin. Foretravel should have designed their coaches for true arctic operation by scientifically keeping the water pipes from freezing.
We'll be in Florida soon, so is this post mute? I don't think so because we will soon be boondocking in the high Arizona desert in Winter.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on December 29, 2017, 09:33:23 am
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Roger & Susan in Home2 on December 29, 2017, 10:34:47 am
Scotty time is always a good way to go. Estimate longer, get it done sooner, you are a hero! Always works for me.
Overnight duration in the middle of the winter is a primary concern. Once you stop you only have what you have when the sun goes down. If your running high loads while driving then between solar and alternator you might come up short. I changed to a bigger Delco Remy brushless alternator to push more into the batteries while driving.
You need to do an winter overnight load survey so you know what you really need.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 10:48:14 am
Tim, thanks for honest evaluation. I know a standard low voltage generator auto start, would probably not work on lithium batteries but can you buy, a gen autostart for your battery bank that senses say, a 80% discharge and them starts the gen?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Jerry Whiteaker on December 29, 2017, 02:20:16 pm
Always wondered why folks with solar panels on an RV do not opt for the most efficient panels available. Space is limited so more efficient panels will deliver more Kwh. Yes, they cost more, but cost per watt may not be so different, I have not checked. Although I did not buy Solar Power panels for my house, I would buy them for my RV should I ever decide to do that. Right now we do not use the coach enough to justify the cost, but not having to run a generator is a big plus.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 03:02:27 pm
Always wondered why folks with solar panels on an RV do not opt for the most efficient panels available. Space is limited so more efficient panels will deliver more Kwh. Yes, they cost more, but cost per watt may not be so different, I have not checked. Although I did not buy Solar Power panels for my house, I would buy them for my RV should I ever decide to do that. Right now we do not use the coach enough to justify the cost, but not having to run a generator is a big plus.
Appears almost all the commercially available rv sized panels today run in the 15 to 21% efficiency range, with monocrystalline being better than polycrystalline, There are panels made, [some by Sharpe] that are in the 40% range, but have never seen any advertised for sale. Size is also a consideration, have heard of 430 watt panels being used on rv's, but most are smaller. In commercial [solar farm] applications, bigger panels can be used. These might be the ones with the higher efficiency. If anyone knows of a 40% efficient panel that fits on an rv, it would be good to know.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 29, 2017, 04:06:59 pm
Four things:
1. MORE PANELS AND BATTERIES Efficiency will get better. I may add, instead of having an all-white "ghost" coach, thin-film, extremely light weight solar panels will be installed on the side of the coach. The price is coming down, but it is still prohibitive. There are two purposes:
- Decoration-A decorative pattern of thin solar panels would look cool. - Power in winter, mornings and evenings. Mounting solar panels on the side of the coach will generate more power when the sun angle is low.
2. INVERTER If the inverter is to be used full-time, more than 1920 watts of solar is required. The parasitic load just to run the inverter is 2.4 KWh per day, or about 33% of the battery capacity. Add low-sun-angle, clouds or shade and my system will not function.
3. CALCULATIONS I now know the calculations required to properly size a system. Should have done that prior to spending big bucks. Lesson learned.
4. BMS The Orion BMS junior is good, but it cannot accurately calculate SOC (State of Charge), even though I have "taught" it. Yesterday, it refused to charge the battery because it thought the SOC was 100%. It wasn't.
That said, we still had heat, water and light in the coach, since the engine battery was wired up as an instant backup to the 48VDC lithium battery.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 04:19:52 pm
That said, we still had heat, water and light in the coach, since the engine battery was wired up as an instant backup to the 48VDC lithium battery. More...Like Quote Do you mean like in starting generator? or some other method? or 12 volt lights, water pump and furnace.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Dakota Slim on December 29, 2017, 06:52:00 pm
Can anyone who has installed solar on their coach describe how they ran the cables from the roof to the basement? I want to install solar on my U320.
Ken
My batteries (and panels) are on the opposite side of the coach from the refrigerator. I ran my cables down through a closet. I also installed my solar controller and inverter in that closet.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Roger & Susan in Home2 on December 29, 2017, 07:15:35 pm
The maximum zero power standby load used by my Victron Multiplus is 20 watts. 0.48 KWH per day.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 08:01:35 pm
The maximum zero power standby load used by my Victron Multiplus is 20 watts. 0.48 KWH per day.
2.4 kwh suggests an unknown load. Even my very inefficient Prosine draws less than 1.5 kwh per day.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 29, 2017, 10:29:39 pm
Yes, another recommendation is not to buy a cheap Chinese inverter, the HGP pure sine wave model from Electric Car Parts Company. It draws too much overhead current and the 48V charger current is only 15 amps, so it takes a while for the genny to charge up the lithiums. I would recommend Victron products because they are not too much more expensive than the chinese equipment.
The Chevy Volt and Nissan Leaf battery packs are about 360 Volts, so they would have to be modified to bring them down to the 48VDC range.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 29, 2017, 10:34:56 pm
Jim C, my panels are 420watts.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 10:51:50 pm
Bruce, do they fit from side to side on your coach roof? Mine are about 78 inches, but they are only 320 watts. I would like to upgrade but only have rear of coach to put panels on.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 29, 2017, 11:01:07 pm
Mine are 51x77or 81 they are longways one On front and one on the back. I suppose you could turn them cross ways and keep the to one side for roof access.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 11:12:32 pm
Yes, another recommendation is not to buy a cheap Chinese inverter, the HGP pure sine wave model from Electric Car Parts Company. It draws too much overhead current and the 48V charger current is only 15 amps, so it takes a while for the genny to charge up the lithiums. I would recommend Victron products because they are not too much more expensive than the chinese equipment.
The Chevy Volt and Nissan Leaf battery packs are about 360 Volts, so they would have to be modified to bring them down to the 48VDC range.
You can buy the individual batteries out of the leaf 360 volt pack. Would it not be easier to buy them, and wire them for 12 volts? That way you could use the more common 12 volt inverters with big chargers etc. 60Ah Nissan Leaf Battery Module (http://hybridautocenter.com/HAC4/index.php?option=com_hikashop&ctrl=product&task=show&cid=91&name=58ah-nissan-leaf-battery-module&Itemid=605)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 29, 2017, 11:17:12 pm
Mine are 51x77or 81 they are longways one On front and one on the back. I suppose you could turn them cross ways and keep the to one side for roof access.
That would work fine, I do not have a rear ladder so rear access is not important. Who did you get them from?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on December 29, 2017, 11:24:15 pm
Jim I got them from Solar Mike in Slab City Ca., he installed the whole system. I do however sea some on the internet.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: kenhat on December 30, 2017, 01:26:14 am
That said, we still had heat, water and light in the coach, since the engine battery was wired up as an instant backup to the 48VDC lithium battery.
Tim
I think this is perfectly acceptable. How often do you travel in these conditions? If often you need to do a ground up redesign/rethink of expectiations. Otherwise do as most of us do in the summer heat. Turn on the generator and run the house air or in your case the furnace/electric heaters. Short days and low sun angle make it tough to rely on solar alone (the further north you are the worse it gets). Thankfully you have options/backups to survive these conditions.
As Roger said an alternator upgrade wouldn't hurt.
Thanks for all your write ups. I'm thinking of going Lithium when my batteries bite the dust. Your experience is helpful to a lot of us. :) With the limited solar setup I have (720w) I've learned that more is better.
see ya ken
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: rvtinker on December 30, 2017, 07:09:31 am
You can buy the individual batteries out of the leaf 360 volt pack. Would it not be easier to buy them, and wire them for 12 volts? That way you could use the more common 12 volt inverters with big chargers etc. 60Ah Nissan Leaf Battery Module (http://hybridautocenter.com/HAC4/index.php?option=com_hikashop&ctrl=product&task=show&cid=91&name=58ah-nissan-leaf-battery-module&Itemid=605)
Each module is 7.6 to 8.4 volts so you can't make a 12 volt or even a 24 volt battery. There is a story on the web of a bus conversion with a 48 volt setup made from a Leaf pack with one module added at: Beginning from this Morning (http://www.beginningfromthismorning.com/)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on December 30, 2017, 08:48:24 am
I built a small 12 volt pack out of Leaf batteries. I had to break open the module/large tin can by unfolding a large metal crimp surrounding the module, which is very hard to do. Then I wired the batteries in parallel and ended up shorting two together. Some sparks but no fire. So it would be better to have a higher voltage pack, say 48 V. And parallel those modules together to get the desired kilowatt hour capacity.
I am thinking of doing a video series called "Tim's Tips" about the Foretravel solar conversion.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on December 30, 2017, 10:27:25 am
Would this one work? Victron Quattro 48 Volt / 5000 VA / 70 Amp Pure Sine Wave Inverter/Charger (https://baymarinesupply.com/victron-quattro-48-5000.html)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Caflashbob on December 30, 2017, 12:08:43 pm
While I like the Victron equipment I have asked before several times for details on their equipment.
Having been in the burn ward long ago I asked if anyone can verify that a Victron piece of equipment is UL approved?
Secondly does anyone know is your coach insurance requires UL approved appliances?
My understanding is no and yes.
Several boating forums mention that they use a Victron inverter/ Charger in their engine bays but Victron does not state their units are not spark generators.
Magnum states they there inverter ps are not certified to be non spark producing. Requires a special design.
So the yacht guys have a possible spark producing appliance mounted in a possible flammable vapor area.
No warning.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Roger & Susan in Home2 on December 30, 2017, 12:46:56 pm
Bob, if you are required to use only UL approved equipment then why keep asking. You can find the answer to this question as easily as anyone else. Victron equipment looks to be certified under all applicaple requirements world wide. UL is doing their best to catch up to the standards used by everyone else. If Victron equipment wasn't safe they wouldn't sell much of it.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Caflashbob on December 30, 2017, 01:55:49 pm
As I did not KNOW if a Victron is UL approved I am asking.
The Victron EU standards mentioned on their website refer to specific steps.
The standards I have seen require a photograph/ drawing of the boards layout to be sent with the manufacturers forms for a approval.
UL reauires two of the particular units for testing in house. Or a certified external lab.
Same question for those who own a Victron appliance. Should be easy to look. I do not own any Victron appliances personally and my inverter repair place (Bio Benefit energy in Costa Mesa,Ca) and my installer had never seen one.
You would think the boat guys who installed an inveter/Charger in a gas engine boats engine compartment might like to know that their appliance was NOT designed or certified to not produce sparks?
I checked on this because i used to carry 5 gallon propane tanks in the bays. A separate bay from a non spark certified inverter would seem to be a good idea.
Magnum is ambulance certified where others are not.
As a oem manufacturer the non UL liability could be a serious liability.
Too many vapors in a rv. Too flammable of construction. To hard to exit quickly.
Every other electrical appliance in your home or rv is UL approved for a reason
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: DavidS on December 30, 2017, 02:11:36 pm
I would think if they have been used in the Marine industry and are a leading brand it would be safe to assume they are safe as in real world experiences they have not been the cause of any destruction.
In the engine compartment of a boat is a lot different than our basements ( I think anyways) .. boats are air tight in those areas and my basement is not.
if it is safe on the water... rest assured it wont hurt you on the road. Are the Magnum Marine rated? Or are there specific units for marine?
What I can tell you when my inverter went out it made a very load pop/bang and melted part of the board .. it was UL listed .. I can assure you that it was super hot and a small explosion would have set off any fumes regardless of the stamp on the outside of it.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Caflashbob on December 30, 2017, 02:28:33 pm
Magnum states in the literature and on their website that they are NOT non spark certified and should not be used in a vapor area.
Not sure if a boats requirements are the same as an rv which needs a DOH sticker to be legal for sale in California.
As far as I know the DOH requires UL appliances as does RVIA stds.
EU standards as I understand it do not cover board interconnections and do not involve physical testing of sample units.
Bay marine sells a lot of Victron appliances for boats. That's nice. I doubt if he ever heard or knows if they are UL approved.
I am not an attorney and do not play one here or on tv but a failure that damages anything including a storage structure that could be traced to a non UL appliance would almost certainly allow an insurance company to refuse coverage...
To allow a legal out is too easy.
Guys I do no care if YOU use and have great luck with whatever appliances you choose. My only issue was the lack of pertinent info.
Non of us has probably seen or been offerred for sale in the US of a non UL approved appliance for a reason
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: DavidS on December 30, 2017, 02:34:52 pm
sometimes you can get info overload and cause some to dwell on substance that isnt an issue when tested in the real world.. California is its own animal and I would assume that if its legal in california it must be good for you.. some ppl live there because it makes them feel safe with all the rules and regulations but at the end of the day it just ppl who think your to dumb to think for yourself..
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on January 05, 2018, 04:26:21 pm
See my Youtube video about this system at: http://www.youtube.com/watch?v=-s1Vx2z8x0M
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Pierce & Gaylie Stewart on January 05, 2018, 04:31:45 pm
With the number 6 economy in the world and almost as many tourists visiting as France, California must be doing something right.
Pierce
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 15, 2018, 07:25:02 pm
For more lessons learned, see my Youtube video at: Tim's RV Tips #2 - Solar Lessons Learned, January 20, 2018 - YouTube (https://youtu.be/dywgaczX9Sg)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: bbeane on February 15, 2018, 09:59:59 pm
Yep California is doing right, broke, infrastructure falling apart, high taxes, no water, not to mention crime in the big cites. Yep they be doing just fine.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on February 15, 2018, 10:09:45 pm
For more lessons learned, see my Youtube video at: Tim's RV Tips #2 - Solar Lessons Learned, January 20, 2018 - YouTube (https://youtu.be/dywgaczX9Sg)
Tim, in retrospect, would you do an all 12 volt system next time?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 16, 2018, 04:34:50 pm
I would recommend:
1. A 48 volt system with at least 20kwh capacity. This would reduce the IR (Current time Resistance squared) significantly and reduce wire size, weight and cost by 88 percent, if my calculations are correct. My 9.2kwh battery does the job, but on cloudy days under trees, the extra battery capacity would reduce "power anxiety".
2. An inverter that has low-overhead, which means low quiescent power draw. Mine has 100 watts...too much. Perhaps Victron. Perhaps two inverters would be advisable: one for low-power demand and one to run the high-power appliances like the microwave, refrigerator, AC, strip heater, engine pre-heater, etc...
3. Separate charger and inverter. If one unit fails, at least you have partial functionality.
4. Backup 12 volt battery if the 48 volt system is depleted. I am using the engine battery for this and it works well. This is needed for essential 12 volt systems like the heater and refrigerator.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: DavidS on February 16, 2018, 08:15:48 pm
With the number 6 economy in the world and almost as many tourists visiting as France, California must be doing something right.
Pierce
I think luck has a lot to do with it.. it has beaches and water on 1 border.. They lucked out with that .. they have productive soil in some areas a some really nice mountainous area in others. The weather for the most part is good..
Just because they visit .. doesnt make it a great place to live... if it was so good they would all be staying there instead of visiting. I would add that it hasnt always been a liberal state it has just gotten worse the last 10 yrs..sad as I live next door in Nevada and typically like Californian ... I dont visit it as much as I want too do to the fact of the gas prices and the idiots that run the state.
Tim it seems a lot of work to reinvent the wheel so to speak.. wouldnt it be easier to just work with the 12v system? In the long run? and cheaper to say the least?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Caflashbob on February 16, 2018, 08:38:38 pm
Victron is popular here. Nice integrated colorful system. I personally wanted more power than our former freedom 25 had so I went with the sw2812. 30 watt idle current consumption. If I changed from mk gels to lifeline AGM the sw has the profile internally for them plus can equalize them if needed
We currently live in south Orange County, ca. Near the beach. Two older convertibles. Folks moved me here 66 years ago. Crowded. Expensive. Run by lunatics.
We have my mom's townhouse to sell in sun city. Las Vegas. Nicest spot in a 55+ community. Nicer adjoined home than our separated detached condo/townhome.
Almost three times more money to buy the so cal place. Neighbors cashing out because of it.
"You can check out but you can never leave" applies to us I think.
74 degrees beautiful day today.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: kenhat on February 16, 2018, 09:25:55 pm
Tim it seems a lot of work to reinvent the wheel so to speak.. wouldnt it be easier to just work with the 12v system? In the long run? and cheaper to say the least?
Not speaking for Tim but with the research I've been doing on lithium the most popular battery looks to be the 18650. This is the battery Tesla uses in it's cars and is what Tesla will be building at it's new Giga Battery plant plus China has about a dozen 18650 factories. Tesla uses 6,800 of these batteries in the Model S. The battery pack for the Model S is $40,000. Which comes out to about $5.80 per cell. Probably closer to $5 after you delete costs for the battery package. $5 is about what 1 18650 sells for on ebay also. I've seen group buys on the lithium forums for a $1 a battery. The buy was for 20,000 batteries of 2 year old lower mA batteries. The batteries will get cheaper as more factories come online.
The problem is that when you put 4 of these 3.7v batteries in series it's 14.8v. Our systems can probably handle the 14.8v but to charge the batteries you're looking at almost 17v. No current current charger can hit that so you are looking at a new charger/inverter to go with your batteries. At that point price wise the 48v system isn't that much more and has advantages with wire size and a boating industry that has a lot of 48v systems available.
That's how I understand it anyway. Somebody correct me it I have this wrong.
BTW: This youtube Tony Seba: Clean Disruption - Energy & Transportation (https://www.youtube.com/watch?v=2b3ttqYDwF0) total brought me around to deciding my next batteries (1 to 2 years) are going to be lithium and probably DYI. Do a youtube search for DYI Powerwall and start looking around. It doesn't look that hard just tedious.
Just for fun a couple of pics of the Tesla battery pack.
see ya ken
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Jack Lewis on February 16, 2018, 11:42:31 pm
When demand calls for it, firmware might be upgraded to higher charge voltage, depending on mfg. Might be a good question before buying a new inverter/charger.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 17, 2018, 10:27:54 pm
Used Nissan Leaf and Chevy Volt packs cost $3,000. However, they need to be reconfigured for the appropriate voltage for a charger and inverter. This would be a challenging and innovative project.
That said, I believe all motorhome makers should spend the professional engineering time to create a high capacity (20 KWH +) and high-voltage battery and solar panel system design to bring us into the 21st century.
The technology has already been developed and is safe and reliable using EV (Electric Vehicle) and solar industries. The motorhome makers just need the guts to make the change from 100 year-old technology.
The other technology I recommend is replacing the generator with propane fuel cells. This would back up the solar panels when the sun don't shine. Fuel cells are expensive but may be cheaper in bulk.
Imagine a totally silent rig that can boondock anywhere, anytime.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on February 18, 2018, 08:24:42 am
Imagine a totally silent rig that can boondock anywhere, anytime.
Now, imagine what it would cost. :o
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 18, 2018, 08:47:02 am
With new rigs costing $1M, the additional cost would be minimal. The performance gain would be maximal. An all-electric boondocking rig would now be practical. The return on investment would be based on:
- Free power from the sun - No generator or battery maintenance - No campground fees if boondocking - 10 year battery life - Better human health because there are no generator fumes, vibration, nor noise to disrupt the natural soundscape
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on February 18, 2018, 09:16:01 am
With new rigs costing $1M, the additional cost would be minimal. The performance gain would be maximal. An all-electric boondocking rig would now be practical. The return on investment would be based on:
- Free power from the sun - No generator or battery maintenance - No campground fees if boondocking - 10 year battery life - Better human health because there are no generator fumes, vibration, nor noise to disrupt the natural soundscape
Tim, granting you have the battery bank to run say a 250 kw electric motor in your coach for 4 or 500 miles a day, what do you use to recharge that bank overnight before travelling the next day if you do not have a generator or shore power to recharge your propulsion batteries?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Old phart phred on February 18, 2018, 09:56:15 am
Used Nissan Leaf and Chevy Volt packs cost $3,000. However, they need to be reconfigured for the appropriate voltage for a charger and inverter. This would be a challenging and innovative project.
That said, I believe all motorhome makers should spend the professional engineering time to create a high capacity (20 KWH +) and high-voltage battery and solar panel system design to bring us into the 21st century.
The technology has already been developed and is safe and reliable using EV (Electric Vehicle) and solar industries. The motorhome makers just need the guts to make the change from 100 year-old technology.
The other technology I recommend is replacing the generator with propane fuel cells. This would back up the solar panels when the sun don't shine. Fuel cells are expensive but may be cheaper in bulk.
Imagine a totally silent rig that can boondock anywhere, anytime.
All fine and dandy, untill you get a week of overcast, shaded site, a hailstorm that destroys the solar panels etc. Utopia only exists in theory, only to be awoken by reality. Wise people never put all of there eggs in one basket. And economic feasibility SHOULD severely impact a rational persons decisions. Do what makes YOU happy. Trust me, you do not have all the answers, nor do I.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: DavidS on February 18, 2018, 02:15:59 pm
On the Chevy volt battery packs.. can't you use the bms that goes to the Battery pack and just hook into the inverter/charger and the bms will do it's thing?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on February 18, 2018, 02:39:04 pm
On the Chevy volt battery packs.. can't you use the bms that goes to the Battery pack and just hook into the inverter/charger and the bms will do it's thing?
You can probably use the volt bms, but the battery pack is 300+ volts. So now we need an inverter from 300 volts dc to 120 ac for house use, and a converter down to 12 volt dc for your coach systems, if you want to, or you could keep your present 12 v system . And 120 or 240 volt ac input to run the bms and charge the batteries.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Caflashbob on February 18, 2018, 02:43:32 pm
I had a customer long ago who outfit his old FTX with 2,000 nicads he had access to for free.
Elon musk's megafactory is going to build 2170 new dimension li ion cells. Should be less than a dollar per cell sometime coming up.
Requires a temp controlled area and a complicated BTMS.
If we live long enough Dr goodenough's latest breakthrough cells (li ion inventor) using silicone will change the world. Fraction of the price. Three times more energy density. Multiple times faster recharging.
Imagine a 750 mile range electric car that could be recharged in 30 minutes? Or power a coach easily. Electric hub motors?
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 18, 2018, 09:39:03 pm
The solar panels keep the battery 48V lithium charged quite well. However, at Mammoth Cave National Park, we camped in a partially shaded site for six days. No hookups. We reduced the load by running the icemaker one day during the day and putting the ice cubes in the propane fridge.
A modern engineered system would predict power usage and generation and recommend how to shed the load to maintain the battery. A good user interface could show exactly what is happening with the engine and house batteries.
In my case, there are three batteries in a redundant system:
- Primary house battery, 48V lithium - Engine battery, 12V lead acid - Toad battery, 12V lead acid
My RC (Radio Control) charger could theoretically recharge the 48 volt pack from the 12V batteries.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: jcus on February 18, 2018, 10:54:32 pm
With new rigs costing $1M, the additional cost would be minimal. The performance gain would be maximal. An all-electric boondocking rig would now be practical. The return on investment would be based on:
- Free power from the sun - No generator or battery maintenance - No campground fees if boondocking - 10 year battery life - Better human health because there are no generator fumes, vibration, nor noise to disrupt the natural soundscape
Sorry Tim, thought you were talking about an "all electric ", electric propelled coach, which is far, far in the future. For electric only with no generator, think you are pretty close to getting there. But I think like Old Phart, plenty of electrical capacity, BUT, also backup propane for heat, hot water, cooking and refrigerator. Or, in my case, diesel for heat and hot water. [aqua-hot]. As for ac, Parliament, [before they closed] had a design coach that used 48 volt ac's and could run 2 ac's on battery for 20 hours without generator or solar charging. If they had made that coach, would have been $1.5m +.....
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Old phart phred on February 19, 2018, 02:15:55 am
Reduce the A/C load in half by dumping the early 70's technology roof mounted units results in greater run time on any given system=and less $ for install. Standby losses and conversion losses also drop. I was hoping to build an modern A/C unit this winter that inrush current is essentially eqaul to running current, but I am running out of time. Shop building is still 5-8 weeks out. On my coach I think I can get by comfortably on an ultra efficient 9000 btuh unit for the bedroom, further extending run times by beefing up the insulation of the engine compartment and running the bedroom unit off of the alternator and a invertor while traveling. $900-1000 per unit. Economic replacement of my new last summer 1200 watt front A/C is non existent unless I can resell it for $400-500.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 19, 2018, 06:49:55 am
Agreed, our 90's era equipment can be redesigned for better efficiency. Heat pumps have come a long way. Or better yet, do propane-powered ACs exist? Wish I had a regular propane oven.
The problem with running AC or other power hog during the day is that the battery is depleated by nightfall. This causes anxiety. That said, we do a lot of microwave and convection oven cooking during for lunch so the batteries have a chance to charge before nightfall.
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Chuck & Jeannie on February 19, 2018, 08:35:14 am
Amazon.com : Camp Chef Camping Outdoor Oven with 2 Burner Camping Stove :... (https://www.amazon.com/Camp-Chef-Camping-Outdoor-Burner/dp/B0013LLSZG)
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: kenhat on February 25, 2018, 11:10:57 am
Need to clear up a couple of previous statement I made previously in this thread.
The new Tesla Gigafactory will be producing a new battery not the existing 18650. The new cell will be a 21700 or 2170 for short. :) The 18650 is 18mm long and 65mm in diameter. The new 2170 will be 21mm x 70mm. Slightly longer and fatter. Elon claims the highest energy density and cheapest cost. Tesla's (TSLA) cheaper, more powerful 2170 battery cell is the perfect... (http://qz.com/879121/teslas-tsla-cheaper-more-powerful-2170-battery-cell-is-the-perfect-embodiment-of-its-factory-model/)
Also I found this table of the different chemistry for lithium batteries.
LiCoO2 3.7 V 140 mA·h/g 0.518 kW·h/kg
LiMn2O4 4.0 V 100 mA·h/g 0.400 kW·h/kg
LiNiO2 3.5 V 180 mA·h/g 0.630 kW·h/kg
LiFePO4 3.3 V 150 mA·h/g 0.495 kW·h/kg
Li2FePO4F 3.6 V 115 mA·h/g 0.414 kW·h/kg
LiCo1/3Ni1/3Mn1/3O2 3.6 V 160 mA·h/g 0.576 kW·h/kg
Li(LiaNixMnyCoz)O2 4.2 V 220 mA·h/g 0.920 kW·h/kg
It looks like LiFePO4 at 3.3v (4 * 3.3 = 13.2v) would work with current 12v systems without new components. I don't think the current charge profiles in our systems would be optimal for the these but worst case it would take slightly longer to charge as the charger would back off sooner than required.
I leave it as an exercise for the reader to figure out if that will work for you.
see ya ken
Title: Re: 48 VOLT SOLAR LITHIUM SYSTEM
Post by: Tim on February 25, 2018, 06:10:50 pm
Two threads here:
1. Battery Format I have yet to be convinced that having 1000's of small cells is better than four large prismatic or pouch cells, The Nissan Leaf or Chevy Volt batteries make more sense to me, being composed of moderately large-format size. The higher number of cells, the more complicated the BMS (Battery Management System) becomes.
2. Battery Chemistry I am biased toward LiFePo4 because they are relatively cheap and available. I have yet to see Large pure lithium batteries for sale.
Although my 48Volt system is doing well and I will be getting about $3,000 back on my taxes. However, for a limited budget, four large (180 to 400 Amp-Hours) cells could be used with no BMS. I mean, there is a human BMS who monitors for over and under voltage.
In fact, four 400 Amp-Hour LiFePo4 batteries could not only be the house battery, but the starting battery as well. They can put out 4000 amps for 10 seconds. This would save another 100+ pounds of lead engine / starting batteries.
The only caveat is that the LiFePo4 batteries would have to be temperature-controlled to be from 40F to 90F to prolong their life.