48 VOLT SOLAR LITHIUM SYSTEM

Topic: 48 VOLT SOLAR LITHIUM SYSTEM (Read 3405 times) previous topic - next topic

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #25 – December 22, 2016, 11:11:43 pm

Thanks, that is the route that I thought I would have to use.
Ken

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #26 – December 23, 2016, 08:53:00 am

Quote from: Tim – 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)
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 , 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

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #27 – December 23, 2016, 10:10:40 am

Quote from: TheBrays – December 23, 2016, 08:53:00 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.

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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #28 – 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?

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #29 – December 23, 2016, 12:12:13 pm

Quote from: craneman – 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?

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

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #30 – December 23, 2016, 01:11:50 pm

Quote from: Chuck & Jeannie – December 23, 2016, 12:12:13 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
[/quote
Thanks for the link, good info. The '99 U320 roof is quite different but when the time comes I will figure something out.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #31 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #32 – 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

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #33 – 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"?

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #34 – 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

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #35 – January 23, 2017, 01:01:19 pm

Quote from: Tim – 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:

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

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #36 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #37 – January 23, 2017, 09:11:12 pm

Ah, now I get it! It's for the genny starter. Sorry for being dense.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #38 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #39 – December 29, 2017, 09:33:23 am

Quote from: Tim – December 29, 2017, 07:27:07 am

Summary: Get more battery and solar power.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #40 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #41 – 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?

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #42 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #43 – December 29, 2017, 03:02:27 pm

Quote from: Jerry Whiteaker – 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.

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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #44 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #45 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #46 – December 29, 2017, 06:52:00 pm

Quote from: KenKetch – 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

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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #47 – 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.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #48 – December 29, 2017, 08:01:35 pm

Quote from: Roger & Susan in Home2 – 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.

2.4 kwh suggests an unknown load. Even my very inefficient Prosine draws less than 1.5 kwh per day.

Re: 48 VOLT SOLAR LITHIUM SYSTEM

Reply #49 – 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.

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