600 AH Lithium Battery InstallationThis is a project we did to improve and enhance the function of our coach for the way we choose to use it. You might choose to do it a different way or not do it at all.
What we did:
600 amp hrs of Battle Born LiFePO4 GC2 were batteries installed in the space used by 2 8Ds.
Each battery has its own 36 watt heaters powered by the batteries themselves.
Each battery is wired to common bus bars.
Both plus and minus connections are switched.
The plus side is fused. The minus side has a shunt with temperature sensor for a Victron BMV 702 battery monitor
A battery temperature sensor is connected for the Victron 3000VA Multiplus inverter/charger.
A battery temperature sensor is connected for the Sterling 120 amp Battery to Battery Charger.
A custom made battery rack was fabricated.
A Sterling 120 amp Battery to Battery Charger was installed with a remote control/display panel.
The Battle Born batteries and start batteries are charged in several ways.- While driving the ignition controlled Sterling 120 amp Battery to Battery Charger provides up to 120 amps to the Battle Born batteries using a 4 stage lithium battery charge profile. The 240 amp Delco Remy 40si alternator charges the start batteries and provides power to the Sterling B2B charger. The Sterling B2B charger prioritizes the charge level at the start batteries.
- 1200 watts of roof top solar charges both the Battle Born batteries and the start batteries using a Victron SmartSolar MPPT Charge Controller and a Victron Argofet zero voltage drop isolator.
- A Sterling ProCharge Ultra 40 amp 4 stage smart charger charges both the Battle Born batteries and the start batteries using a 4 stage lithium battery charge profile if it is on.
- The Victron 3000VA Multiplus will charge the Battle Born batteries in a multi-stage lithium friendly change profile if the charger is on.
- The Victron 3000VA Multiplus will charge the start batteries as well if it is on.
Cold Weather Operation.
I added two 18 watt thin film heating panels (about 3"x3"), one on each side of the batteries and covered them with a layer of thin foil backed insulation. The pair of heating panels provide up to 36 watts of heat to each battery. There is an on/off switch for the heating system and a high/low switch as well. For all six batteries the total of the contact heating panels is 216 watts.
The batteries themselves provide power to the heaters. In extreme conditions the heat generated by the panels as well as the internal heat in the batteries because they are providing about 3 amps each will warm the batteries enough so that they will begin to charge. Once they start to charge that process generates more internal heat until the batteries are fully functional even at low temperatures. It is really the internal battery temperature that drives this process not the ambient temperature.
Connections.There is no longer a House and Start battery isolator. There are no combiners or any other inter-battery bank connections. The boost solenoid is still functional if that need arises.
The Sterling Battery to Battery Charger is located in the LP bay (no big LP tank any longer). Power to it comes via a fused 4/0 cable from the start battery power stud in the engine bay to a bus bar in the LP bay. The B2B charger in and out sides (120 amp max) are connected with short 2/0 cables. The output side is fused and connects to another bus bar. A 3/0 cable from that bus bar connects to a coach common positive stud behind the white panel in the main storage bay. When not powered the Sterling B2B charger effectively isolates the start and lithium batteries.
Power from the lithium battery connected bus bars in the LP bay power a smaller Victron 800VA inverter located about 4 ft away through a switch and fuse. This smaller inverter powers the residential refrigerator and all of the front end electronics through a distribution panel and circuit breaker.
The Delco Remy 240 amp 40si alternator connects to the start battery power stud in the engine bay with a 4/0 cable. A short cable connects to the start battery side of the boost solenoid and then another cable to the start batteries.
A house battery power stud in the engine bay connects to a coach common positive stud behind the white panel up front with a 4/0 cable. A short cable from the engine bay house battery power stud connects to the house battery side of the boost solenoid.
Solar power and the Sterling ProCharge Ultra charger are connect to the start battery power stud and the house battery power stud both in the engine bay. Solar power uses a small Victron Argofet zero voltage drop isolator to split power to the house and start sides. The Sterling UltraPro charger has independent outputs for the house and start sides.
ResultsAfter removing our 8 year old Lifelines and the upper and lower battery racks (about 580 lbs) and the 4-DC400-6 Full River Batteries and the battery rack (about 550 lbs) and replacing them with 6 Battle Born GC2 batteries and a new rack and cables (about 180 lbs) our coach is lighter by about 950 lbs.
The Full River DC400-6 batteries found a new home in Ted and Karen's coach. My three aging but functional Lifelines as well as Ted's two aging but functional 8D batteries are now being charged by our home rooftop solar array and will provide 2-3 days of basic lighting, well pump operation and refrigerator power in the event of a power failure. In 19 years our longest power outage has been an hour.
Comparing notes with other Lithium battery users confirms my expectations that on most days solar will fulfill or exceed our daily needs and leave the batteries at or near full charge. We expect to be independent of power connections or generator use when we choose for extended periods of time. We expect to never have to replace a house battery during the time we think we will continue to own and use the coach.
Parts Batteries
100Ah 12V GC2 LiFePO4 Deep Cycle Battery - Battle Born Batteries (https://battlebornbatteries.com/shop/100ah-12v-gc2-lifepo4-deep-cycle-battery/)
Battery to Battery Charger
Sterling Battery-to-Battery Charger - 12V-12V 120 Amp (https://baymarinesupply.com/chargers-inverters/sterling/sterling-battery-to-battery-charger-12v-12v-120-amp-input.html)] Sterling Battery-to-Battery Charger - 12V-12V 120 Amp
Victron Argofet Isolator
Victron Argofet Battery Isolator (https://baymarinesupply.com/electrical/isolators-29/argo-fet-battery-isolator.html)
Was it worth it?Many will ask this question. This is definitely an upscale extra cost choice. Lithium battery prices are coming down. the Charge while driving and cold weather operation issues are easily dealt with. Most of us are never going to be anywhere where the high temperature limits are exceeded. It is worth considering if:
- You plan on owning your coach for a longer period of time.
- Independence from land lines and a generator are a priority.
- Weight savings is a consideration.
- You have or are going to add sufficient solar capacity.
- You power demands are going up, maybe from a 12v or 120v refrigerator conversion or a residential refrigerator.
- Or maybe you just want to do it.
We think it will prove to be worth the effort and expense for our purposes. Nothing else really matters.
Special Thanks No project like this is done without some help and learning from others experience.
Alan Ferber at Bay Marine Supply for his endless support, encouragement and help with prices.
Peter Flemming whose encouragement and critical thinking help make some of these projects work.
Ted and Karen whose choice to move up to Full River Batteries forced me to make a choice helped make this a bit more affordable.
George Denninghoff whose trail blazing I followed and real world experience helped me see what was possible.
Thanks!
Pictures
See my media album Lithium Battery Installation
Have you been using it yet? How is everything working? I am having an issue with my bmv712 and SOC.. keeps dropping but never goes back up.. redid the connections on the batteries and made sure everything goes through the negative shunt.. volts are always good but SOC never goes up.. I installed the alternator bim for the lithium's but not sure if it actually works and so far not a fan.. will look into the sterling products.. want to charge from the alternator as we drive.. 1 thing I noticed is the solar is not kicking in as high as I think it should.. when AC pulls 2000w off the inverter , split kicks in about 500w.. not sure if that's normal or not.. when I installed and programmed the solar controllers originally I had seen over 900w off the 1200w on top..
Sry to hijack a little but . Like always you did a great job!!
Not sure it applies in your case. But I had the same problem, SOC would not go to 100% Checked with Alan and he said to check where I had my solar connected. Turns out I connected it directly to batteries so shunt was reading loads out, and inverter charging in, but not solar in. Moved solar to the shunt and now goes to 100%
Is all 600 AH useable? And, if you pull 600 AH out of battery bank, where does that leave the (total bank) SOC?
Battle born says their batteries are usable to 100%.. SOC Would be at zero.. think you might be asking about volts?
Tests I've seen on battle born is they they have say 130ah for a 100ah battery so the percentage is worked in the total of ah.. I believe..
Nice job! Well thought out and nicely executed.
Don
When I had 400 ah, ran them down till BMS shut off battery at 1% SOC. About 11.9 volts. Then charged them up will solar and inverter. Took less than 3 hours to get back up to 100% SOC
All of the charge and all of the loads have to connect to the load side of the shunt in order for all of the in and out to get counted correctly. We did a bit of rearranging on Ted and Karen's solar install to make that part correct.
Battle Born says you can use 100% of the SOC (I set mine based on 600 ahs) but my planning uses only 75% consumed Like all batteries a little less stress and the cycle count goes way up. This compared to the 1500 ahs I had and trying to stay less than 25% consumption for longer battery life with those gives me about 20% more useful capacity while still maximizing cycle count. And I still have 150 ahs in reserve. And almost 1000 lbs less weight.
For purposes of my BMV 702 the total capacity is set at 600 as are all of my capacity calulations.
I have tried every function out. The coach sat in the barn for 2 week, no sun, no charger. Lithiums went down to 13.6 from 13.7. Start batteries were still at 12.7. Started right up. Ran out to see how much amps was going where. Plenty into the starts for a short period, about 6 amps into the Lithiums via the B2B charger, exactly what I expected. Pulled it out of the barn, shut it down and it was at 100% in about 20 min. Tried the boost solenoid, that works. Tried the big switches to isolate components, they work. Multiplus works as expected but it is normally off. My Sterling charger gets to 13.6v and 3 amps into all batteries quickly and then shuts itself off. It wakes up after some time to see where things are and charges as needed or goes back to sleep. Refrigerator and small inverter are working as expected.
Heading for South Dakota next week for 10 days. So far works as designed.
Can't wait to hear results from your trip..
As always, great preparation and execution Roger! Since you have almost the same coach as us, where did you run your solar wires down and how far before you reached the controller? I know you want to keep the distance close, but with the slide, that was my dilemma. Second question, I have the same set up in my battery compartment and was wondering if one could cut out that bracing above or is that a no no? Most likely is, but thought I would ask!
Joe,
You could but you need to remember that is a strengthener to offset the hole in the side that was removed for the slide. So I would go with the No No.
Mike
Thanks Mike, kind of thought that, but sure would have been nice to have it removed!
Joe, my solar cables come down from the roof through the refrigerator vent and through the floor to the manifold bay. They connect to a fuse block, each panel is individually fused. Then to a switch, the Victron controller, another fuse on the + side and then back to the engine side of the inside of the bed box.
All of my panels are wired in parallel, #8 or #10 wire depending on where they are mounted, directly to the fuse block.
3 panels when these pictures were taken, some shadow lines from panel cabels,
See
A Second House Battery Bank, Solar Panels, 2 New Inverters (https://www.foreforums.com/index.php?topic=31957.0)
Well done. ^.^d
Thanks Roger! I have the room behind the new fridge, but was trying to wrap my head around how to get these wires up to where the batteries and inverter where to keep the cables short. I have read to keep the cables there as short as possible for less drop from the solar panels. So thinking was getting the solar cables into the bay with the batteries, controller and inverter.
I plan on installing 6 200 watt panels on top of coach when we get back to our son's home and run the wires down. From there I was clueless! Duh!
From the manifold side of the wet bay I went up through the floor into a closet in the bathroom, through the bottom of the closets and under the drawers to a chase that goes under the floor for about 18" end comes up in the pass side end of the space at the end of the bed. Then through the wall to connections on the other side. Size your wires based on the round trip length, the amps and acceptable voltage loss (<3% is OK, 1% is a better target).
Bos'ns' Corner - Wire Size Calculator (https://baymarinesupply.com//bosns_corner_wire_sizes)
It is about 10 ft one way, use 20 ft for length, my max current is 70 amps, charges at 13.4 volts. I used 4 ga wire. At 85 amps you would want to use 2 ga wire. You will rarely be at max output but that is how you need to size the wires.
Nice Roger. You won't be disappointed with the lithiums.
Thanks for the positive feedback Roger. Really enjoyed seeing your finished product on our visit. Your coach, shop, home reflect the aspirations of a true craftsman.
You will need to research how to wire your solar panels, parallel, serial, and/or combination. Serial ups, combines, the voltage, thus requiring a smaller gauge wire. Then comes selection of solar charger or combination of. To wire my 4 panel, 1200 watt system I used a combination of both. Two in series at each end of rv to combiner box on roof and the two in parallel to the 100 amp, 1400 watt at 12v, 12v solar charger.
Roger, your system is awesum. For me the best part is it matches your needs. I am not sure what mine is now with my increased solar capability and if I'll be plugged in or not. You were the one that taught me that lesson of measuring for my needs. Congrats on completing your system with well thought out components that match your needs and comfort level. Thank you so much for your post. You have given me more to measure and research now.
I have started with the following similar to a Kill O Watt meter, called a Currant that will measure, and store daily kwh usage..
Currant Bluetooth Smart Outlet with Energy Monitoring - - Amazon.com (https://www.amazon.com/Currant-Bluetooth-Outlet-Energy-Monitoring/dp/B078X8B8GL)
Series or parallel or a mix is always a discussion point. Wire them in series and shade on one panel makes all in that series string produce nothing. Wired in parallel each panel is independent and shade on one has no impact on the others. The cost savings from one or two gauge smaller wire is offset by combiner boxes and fittings on the roof (where you have to go to service it). The cost of one or two gauge bigger wire is insignificant compared to the total project cost. Wiring them in parallel gets your fusing, combining, service and installation all at ground level. It was an easy choice for me. Do your homework and planning carefully.
Thanks Jack, we are going on 9 years owning our coach now and are active users, 5-6 months a year. It takes time to figure out how you want to be able to use your coach, what works for you and what your coach lifestyle looks like. Everyone has a different and evolving one. Move deliberately ahead based on what works for you. That seems to work for us.
I copied Rogers installation and went all parallel. When I hit 1237 watts on my 1450 watts of solar last year one day I couldn't figure out why it didn't go higher. After talking to Allen at Bay Marine when I bought my Phoenix 1200, he informed me I had hit the limit on my 85/150 solar charger and it was shedding watts. Because I am adding one more panel this winter he suggests I take one on my current panels out of the 85/150 and put it with the new panel on a seperate solar charger if I want to utilize all the watts should circumstances allow it.
I was asked what the Sterling Battery to Battery Charger does when loads are applied. So yesterday when we stopped at a rest area with the engine running at idle the B2B output side was charging the Lithium battery pack at ~7 amps. I turned on the Victron Multiplus and Susan turned on the microwave oven. I checked again and the output from the B2B charger was 70 amps. An amp or so for the Multiplus leaves 62 amps for the MW. The Lithium batteries were at 13.5 volts so that is about 840 watts. About right for the MW.
I'm at the limit on my 75/15 Victron smart solar with 400 watts of panels. I'm probably loosing a couple amps at full sun. I'm thinking of adding 2-4 more panels this winter and if I do I'll probably upgrade my solar charger.
Roger, can you post up a pic or add to the description of the Sterling display.. Any reason for the one you chose? I did not see it anywhere in the pics but you had mentioned you had one.. Just wondering..Thanks
David,
Sterling Waterproof Battery-to-Battery Charger Remote (https://baymarinesupply.com/chargers-inverters/sterling/sterling-waterproof-battery-to-battery-charger-remote.html)
The remote display shows charging stages, input volts and amps and temperature (at the charger) and output volts, amps and temperature (at the batteries), battery voltage as well as alerts and alarms. You can turn on or off the audible alarm.
Roger,
When I got back from a week of boon docking (just generator) in CO this summer, I had concluded that some charging upgrades would be nice before any more of that. Started researching this forum and found your very thorough post about installing surplus solar panels and associated equipment. Great post. Thinking your step by step account will align well with my U295, same length and year as your coach. Anyway, about to start with this same B2B charger you have, but want to keep expansion in mind. I can't seem to find the post I mention and really want to review it again before I get going with this. Could you put up a link to that? Was under the coach yesterday and noticed the conduit into the compartments from the rear looks a little snug. I can't remember what all you fought to run through there, but If I should, I want to at least consider fishing other wires through for future use along with the B2B wiring (solar, more battery capacity, etc.).
Steve Busenbarrick
2001 U295 3610 - 2015 Jeep Wrangler 2dr
Benton, LA
Benton, LA
Steve,
Not Roger but this may be the one you are looking for.
600 AH Lithium Battery Installation (https://www.foreforums.com/index.php?topic=37729.0)
Mike
Thanks. Looking for something older. From right after the big first push of his major power upgrades. I think he'll know what I'm talking about when he comes on.
Steve, Maybe this one.
A Second House Battery Bank, Solar Panels, 2 New Inverters (https://www.foreforums.com/index.php?topic=31957.0)
I ran extra 4/0 cables from the the front end at the back end of the bay where the batteries, fuel tank, LP tank and in my coach the AH are through the center bay roof cable way, into the space over the tanks in the wet bay and out under a frame member, through the cable guides around the differential and transmission to the area at the end of bed in the engine bay.
Going the other way would be tough. I removed the center bay roof cable cover and tidied things up to make the cables easy to thread through there. The hard part was over the tanks and through the fairly small opening in the rear bulkhead which leads right into a frame member. I used a fiberglass rod used for fishing wires to move a cord with a big nut on the end through the space and opening and when I released the nut it pulled the cord down. The small cord pulled a 1/4" rope through and then with that the cables. My neighbor fed the cables with lots of wire lube. I got very dirty under the coach pulling the wires from that end. Ran the neg cable first through the cable guides over the differential and transmission. Then the positive cable with the corrugated cable cover where needed for abrasion resistance. Use high quality strong cable ties, lots of them.
The rest of it is mostly mechanical, installation and common sense, use switches and fuses where you should. Don't skimp on any safety item.
This step used a Sterling zero voltage drop smart ProSplitter instead of a diode isolator. Charging the house batteries, the 8D battery set and the L16 battery set wen through this. When I switched to Lithiums I needed a smart safe way to charge them. I now have no isolator. The B2B charger uses power from the alternator to charge the Lithiums using a multi step Lithium friendly charge profile.
With adequate solar charging you could probably get by with a 60 amp B2B. With your OEM LN alternator you still need an excite and sense with but with out a diode isolator you can back the voltage down to 13.8 volts or so.
Let me know if you have questions. Another Forum member is midway through this process in just one step. Alan Ferber at Bay Marine Supply can help with all of the parts. Justin Cook there is another good resource. Be sure you mention you are on the Forum. There are discounts available.
Roger
Roger,
Thanks. That's what I was looking for. As I've observed in your other traffic on here, a very thorough and helpful response. So much more than I asked for.
After studying these posts, I still may have questions or need advice and will PM those, if you're willing to entertain them. Just starting this and thinking the 120A B2B is what needs to come first in my case, but hope to slog ahead to adding 900ish watts of solar, etc. as coach bucks become available.
Thanks again!
Steve
Steve, glad to help.
Roger
Can't say enough good things about Bay Marine!
I bought a Sterling 60amp charger a couple of months ago. Installed it in kind of a hurry and left the battery temp sensor in the box to hookup later. Being the brain dead idiot I am, I ended up throwing the box away with the sensor. Luckily I was in Pio Pico Thousand Trails just outside of San Diego and Bay Marine was close by. Called, talked to Justin and confessed my dumbness asking if I could buy just the sensor. Justin checked and found that they don't carry just the sensor since it's included with the charger but he said "I do have one on our test bench I'll send you if you want it". Told him I was in the area and would stop by and pick it up.
These guys don't really have a store front. They do all their sales over the web & phone. Drove up went in and the shop is just 2 desks manned by Alan & Justin with the warehouse behind a wall. Justin looked at me and said you must be Ken and handed me the sensor "no charge!". I talked to Justin & Alan for about 10 or 15 minutes about the forum and traded gossip about Roger & Don. Ha! (all good stuff!)
Two of the nicest guys you would ever want to meet. They are very generous with their time and their extensive knowledge. (and the 10% off their already reasonable prices is pretty awesome too!) I've seen Justin pitch in on some comments on the forum so they do read it.
Alan/Justin thanks for doing what you do!
I have no affiliation with Bay Marine other than being a very satisfied customer!
Bay Marine Supply (http://baymarinesupply.com/)
see ya
ken
Thanks
@kenhat !
We love what we do, so it's easy to do it well :)
Just curious if there was a specific reason you went with the GC2's instead of the Group 31 BB's? Size? They are more expensive and not as easy to get to the lugs when positioned end to end. I'm getting ready to do a similar setup (without Sterling or solar right now) and was just wondering before I pull the trigger. Thanks!
I have a Sterling in our all-electric 2019 Promaster Camper Van with 200ah Battle Born, I never saw the need in the coach? They just upgraded the Sterling models a few months ago. mines rated at 60 Amps, but I pull about 48Amps while driving, 220A Alternator. Now Victron makes one, saw it at the Victron booth @ TinyFest in San Diego in February.
GC2 size was selected because it fit in the space where my OEM batteries were. The standard BB Batteries have a different footprint and at most 4 would fit. A snug fit. The U320 has a bigger fuel tankd and less room than a U270 for example. Measure carefully. I got a Forum discount at Bay Marine on these batteries and all the other components. and when you buy six they ship on a pallet with only one hazmat charge instead on the same charge per battery. The end price was not much more to get the fit I wanted.
I removed all of the original racking and made a new much lighter weight rack to hold the GC2 batteries.
The 2001 with a slide has a truss under the slide. I cut out the fiberglass to make more holes for access. Added a volt meter and a switch for the battery heaters. High/off/low switch in the cab.
The Sterling B2B remote display is shown. I will take a picture on mine as installed. It shows start and house battery voltage and temps and more plus any error codes. I used an ignition powered source to turn it on with an additional delay timer. I started with the 120 amp version but it seems there is a software issue in that version somI swapped it out for the 60 amp one. My Lithiums get the maximum cycle life with a charge rate at 20% max. For 600 amp hrs that is 120 amps. You can (and I may do it) use two 60 amp B2B chargers in parallel.
Victron makes a similar device. It needs to have the negative cables installed as well as the positive cables. And I think these are only 30 amp max.
Here is the Sterling B2B remote in my display panel. 2 Victron BMVs, 2 Digital Volt Meters, Victron Color CCGX panel
Followup
We just finished 7 days dry camping at Gros Ventre in the Grand Teton National Park. Every night but two was in the 30s. The other two were upper 20s. One day (in between the cold nights) got to 45°, heavy clouds all day and rain most of the day. The other days got into the 70s and were generally sunny with some shade in the afternoon We have a residential refrig, 600 amp hrs of LiFePO4 Battle Born batteries. The AH was on for heat. We averaged about 3.6kw production each day except fot the rainy day. We started the week at 100% SOC and ended at 76%. Our avg daily consumption was about 2.8Kw. We were about 270 watts per day short in production vs use over the week. The lowest we got was 49% SOC. An all day rain was tough to overcome
No generator use at all.
We have been here before in sites with little or no shade and produced more than 5Kw. Without the afternoon shade or the rainy day we likely would have been back to 100% SOC. I have room for two more solar panels, time to start shopping.
It is nice to see this work for us. It would have been tough on AGM or GEL batteries, they are harder to finish charging and need to get back to 100% SOC every cycle. LiFePO4 batteries do not. We were using about 1/3 of our capacity everyday. Battle Born considers this 1/3 of a charge cycle and with as many as 5,000 cycles these batteries should provide many years of service. They are worth considering when it is time to change your AGM or GEL batteries. You need less total amp hours of capacity (because you can use all of the battery capacity and are likely to get twice or more the life compared to AGM or GEL batteries.
Hi Roger
Nice install. I'm thinking 600 AH BB Batteries with similar Victron Charger/Inverter and battery monitor when we move to the new the 34' U270 coach. I currently have 300AH of BB Batteries and 800 W of solar on the roof in my class C. That gives me plenty of charge and power in this smaller RV and we rarely run the generator.
How is your experience with 1200 W of solar for your 600 AH batteries? Would you have put more on the roof if you were to do it again or is the 1200 more than enough for you daily needs? We are mostly off-grid and don't anticipate installing a residential fridge. If I can get away with 1200 W I'm inclined to do that rather than load up the roof any more than I have to.
Thanks
I think you'd be fine with 1200w & 600ah. As long as you have decent sun exposure you should be able to fully recharge every day, and possibly go for several days depending on how conservative you are with your usage. I'm doing fine with 1065w and 400ah of BB's, and I do have a residential fridge. I like keeping my roof a little more accessible than it would be with more panels.
Our 1200 watts of solar will recharge the watts we use from our 600 amp hrs of LiFePO4 batteries on most days. Sun angles, clouds, partial shade from trees and lots of other factors come into play in that equation.
After a week in the Tetons on solar and battery alone with some shade every day and one all day rain we ended up about 2000 watts short of what we used. If it had been only a partial day of rain we would have broken even.
So I am considering adding 2 more panels, maybe 600-700 watts. That does a couple things, makes some shade and a rain day in a week easy to recover from and probably will add a few weeks on either end of the season where we are likely to get enough solar to be self powered without a generator. How much you can get on the roof depends on panel size and arrangement and how much room you want to leave for access. The newer 60 cell panels are shorter and can be higher power than my 300 watt panels.
We are in an RV park in Alabama now, plugged in. We are using land line power for the residential refrigerator, run one or two diesel cycles a day on the AH, otherwise off, inverter/charger is off, my small smart charger is off. Very little other land line use. We are cycling between 100% SOC and 90% SOC day to day. We're back to 100% before 10AM today.
As long as your daily watts used are well within your battery capacity with enough reserve to get through a rain day you have enough. For many with an LP refrig 400 amp hrs seems to be enough.
Make sure your max charge rate is not more than 20% of capacity for maximum battery cycle count. This can be as high as 5000 for Battle Born batteries. 100% to 50% and back to 100% is a half cycle. For the same use, a bigger battery set will use smaller cycles, more life and more reserve.
So far this experience has been better that I expected in every regard.
We are at 1140 watts and 400ah. RV fridge. We have a 50" 4K tv and use the microwave and latte maker in the morning but never start the generator. All lighting is LED. We do shut off the inverter at night or when gone from the coach for any length of time. Even in winter, we are at float before noon. Overcast takes only a little longer. AGM batteries are going on 12 years old and still working fine.
I just removed the old Taytronics inverter and replaced it with a sine wave 1500 watt and an old Trace 1500 watt for a back up. Just turning the Taytronics on really dropped the voltage plus you could hear the hum throughout the coach. The new Chinese inverter can remain on with very little idle current. The Trace is also very good and with the setting at pulse, almost no idle current.
Our coach is 36 feet and the panels were purchased we got home from buying it in 2008. The newer panels are much more efficient and we could have 1700 watts up top with the smaller footprint of the new panels.
Usually, about 65% continuous of inverter RMS rating is the figure for maximum life.
If you frequently camp where shade reduces the output of the panels then the more the batter.
The old style inverters (heavy-transformer) will triple the start up wattage while the newer pure sine wave (weigh nothing) will double the start up wattage for a limited amount of time. I have a couple of switches so I can switch between inverters when I want to start a small compressor.
Pierce
For Joe Allen's question about the steel supports.
Could they be cut to allow easy access to the space behind. And then construct strong attachments to re-position the steel support so it could do its job.
Thanks, Pierce, Roger and Bdale. I usually use between 20 and 25% of my 300ah daily and generally fully charged up by 11:00, so It seems like 1000 to 1200 with 600AH BB should be fine. I don't expect to be using computer, TV, micro or Instapot anymore than I do now, so the real variable will be how much more the lights (will be going to 100% led) and Foretravel internal coach systems draw over the current class C. I'm guessing the the auto-leveling, and other internals, along with the luxury if using the propane furnace a bit more often than we do is going to be the greatest draws. We've been are full time and very spoiled by the solar/BBs. :) The biggest issue is forgetting to give the generator a run once a month or so.
I just ordered two Lithionics GTX315s for ours. We had 600aH of AGM & 740w on our fifth wheel and it was just barely enough. Any shade during the winter pretty much meant the generator was coming out. I figure between the added draw of the FT and the residential fridge, 630ah of lithium should still be plenty but I'll have room to add a 3rd battery if I really want to get crazy. Hoping for 8x180w panels on the roof but we'll see... I don't want racks to elevate them above the AC/Vents and un-shaded space on the roof is at a premium with the wineguard traveler in play.
Elliott,
Ours are about 1.5" above the roof, just enough to allow air and the flex electrical conduit underneath. The wattage is a maximum and rarely reached in real work conditions. The cooler the panel is, the greater the output. 36 or 48 volt panels would be great and minimize the resistance loss down to the controller. I made most of our roof mounts. Easy and the finished product is tidy. No wires visible.
Pierce
In the 9l-01 coaches with a slide there is a steel truss abou 8" high that extends from the from bulkhead to the rear just under the floor and just inside the bays. This is primary structure, don't alter it in any way. I remove much of the fiberglass skin inside and out to allow for access. In this space sized as it is the only way to get six batteries in there is to use the GC2 size. Measure very carefully, it can be an expensive error if you do not.
And for forward wall of the battery space supports the fuel tank. The back wall has all of the big 12v wiring connections on the other side. And the inside wall supports both sides and has the AH on the other side.
Work with the space you have.
If you ever want to get your hand under the panel to attach nuts and bolts then 2" or more is helpful. Minimize the effects of shade by wiring all of the panels in parallel. Some argue you can save a few bucks on wire costs with series wiring but that comes at a major performance degradation in partial shade. A few bucks on wire cost is insignificant compared to the whole project.
Great review. We just installed 500 amps of Battel Born ourselves. I was amazed while driving the 1800 miles, from San Jose to Nachodocious, that we did not need to turn the generator on an ounce! The engine recharged the system while driving. It charges so fast!
Rodney, You do not want the alternator to be recharging your LiFePO4 batteries directly. Use a smart multi stage Battery to Battery charger from Sterling or Victron between the alternator/start battery and the Battle Born batteries.
We really like the performance of ours. Solar alone keeps our batteries charged back to 100% almost every day.
Roger, Rodney has an IH45 with a 320 Amp alternator. Would that make a difference?
The size of the alternator doesn't matter much. You get the maximum life (cycle count) out of Battle Borns if you charge them at no more than 20% of capacity so for 500 AH you want to keep the charge at or below 100 amps. A Battery to Battery charger takes what ever the alternator puts out and uses what it wants to charge the house batteries in a multi step charge profile at whatever the max charge rate of the device is. Victron makes a nice 30 amp B2B, Sterling makes a 60 amp B2B charger. When the ignition is off (or engine is not running) they also act as an isolator so no other isolator is needed. And as I understand it you can put these (of the same type and size) in parallel to get 60 amps from the Victrons for example.
I have a 60 amp Sterling, it works well. Now that the Victrons are available I like the way they get setup and work and might have used those but more $ to get to 60 amps.
All of these can be set to any battery type so they are nice to all kinds of batteries.
Another question for Roger.
The IH45 will run the second AC (Kitchen area) off the inverter. I only do this when going down the road and it is not too hot where I need to run more then 1 roof and dash AC's Running numbers it looks like that roof AC is using around 111 amps from the alternator. Is there a way this could be done without reducing the life of the batteries?
I have to think on this a bit. Normally, the alternator, the house batteries and the inverter have a common connection point. With a B2B charger putting in say 120 amps into the batteries and the inverters pulling 110 there isn't much net amps left going into the batteries. Now if you add in solar there might be enough.
This might be a good question for Oscar (valento on the Forum) he has lots of Lithium capacity, inverters, solar, charging schemes and more from AM Solar to get an idea how they did it for him.
Correct. This is what I'm doing next Sunday