solar lithium idea ....... am I crazy

[SiteTrek]

I want more 12-volt storage and the ability to use 12 volts to power 110-volt appliances in dry camping which I prefer to do and not have to run my generator just for quick uses and if my wife needs to use a hair dryer at night and disturb others.
My first thought was to add roof mounted solar and just replace the house batteries with a 200 AH lithium but after talking to some of the battery manufacturers, and the tech at M&M Electronics, there are major issues. One, most lithium batteries will not work for the emergency start function, two the battery control center is not adequate to charge lithium batteries, three my inverter will also not charge the lithium batteries not to mention the location of my house batteries is exposed to outside temperatures.
I am thinking about putting four 100AH batteries under my bed and doing something like the attached picture.
With this type of setup I would be able to run everything but the A/C off 12 volts.

[rosebud1218]

Your requirements and additional details may help you to more confidently determine whether your proposed or another setup will best meet your and your wife's off-grid/off-generator electrical power needs.

Requirements:
(1) Run 110v appliances & plug-in outlets from lithium battery bank only
(2) Charge lithium battery bank via solar or direct AC current

Unknowns:
(1) Electrical draw of individual 110v appliances that will use parallel wired lithium battery bank (including 110v outlet for hair dryer, etc.)? I believe this will require a separate inverter to power your 110v appliances from the lithium battery bank.
(2) What, if any, 110v appliances will be used simultaneously?
(3) Will existing 12v components (e.g., water pump, blower fan, exhaust fan, lighting, etecetera) draw power from existing house batteries or from lithium battery bank?
(4) What is the estimated length of time you expect or need to have individual the appliances/outlets or combinations to be drawing power from the lithium battery bank?
(5) What is the capacity and number of solar panels you expect to use?
(6) How quickly can/do you want a solar-only recharge of your lithium battery bank?

I went through a similar exercise and concluded that it would be possible for me to use a portable "solar generator" (Jackery 1500 Watt Lithium Battery Bank) with 4x100 watt solar panels. When off-grid/off-generator I use this to charge my existing lead-acid house battery (off of which all my 12v circuits run) and run my 120v circuit supported microwave and plug-in outlets. I simply plug my 30A shore power connection into the Jackery as if I was on-grid and, as needed, maintain or achieve recharge with solar. That said, my power consumption needs are likely considerably lower than yours (my Wife and I have a 17' Teardrop TT).

Best of luck in your efforts & safe travels!

[SiteTrek]

In answer to your unknowns
(1)
I have in my drawing a 3000w inverter connected to the batteries
(2)
Most likely one at a time. The only appliance of any consequence is a 1200-watt microwave.
(3)
With the SPDT switch all could be ran off either
(4)
For less than a few minutes
(5) I currently have a 200 and a 300 foldable panel but If I do this I will put 600-1000 watts on the roof
(6)
With 4 batteries I would have quite a reserve and with my proposed roof panels I should be able to keep them up.

[rosebud1218]

I see a "converter" in your drawing, but not an inverter, attached to your lithium battery bank. Given the microwave is the single electrical appliance will be drawing the most at 1200 watts, even running this for an hour consumes ~100 amps, leaving you with plenty of gas in the tank for other needs. The inverter will also consume power when in operation, but, again, you should have plenty with your 400 amp hours in the bank. Agree as well that with 1000W of solar, with your MPPT charge controller, ~3-4 hours of peak sun should provide you with a full charge, if starting at 50% discharge.

Seems like a robust and totally sane approach.

Good luck & safe travels!

[hamm2018]

Originally Posted by SiteTrek

I want more 12-volt storage and the ability to use 12 volts to power 110-volt appliances in dry camping which I prefer to do and not have to run my generator just for quick uses and if my wife needs to use a hair dryer at night and disturb others.
My first thought was to add roof mounted solar and just replace the house batteries with a 200 AH lithium but after talking to some of the battery manufacturers, and the tech at M&M Electronics, there are major issues. One, most lithium batteries will not work for the emergency start function, two the battery control center is not adequate to charge lithium batteries, three my inverter will also not charge the lithium batteries not to mention the location of my house batteries is exposed to outside temperatures.
I am thinking about putting four 100AH batteries under my bed and doing something like the attached picture.
With this type of setup I would be able to run everything but the A/C off 12 volts.

In September we added solar for our rig. We had installed 1600-watts of panels, 8-120AH Elevation brand batteries. We had 2–3000-watt inverters added, one to each leg of the breaker box. Plus, the other needed requirements for the system.
We have run 2 A/C units for 4 hours and did not run the generator.

[astrocamper]

We bought our Artic Fox 22G trailer 2018. We started with 640 watts of solar on the roof and 4 100 amp-hour BattleBorn batteries. We used a Honda EU2200 when we wanted to use the air conditioner for which we installed an easy-start.

My wife complained about me running the generator too often because I liked using the air conditioner when it was hot. We spent 8 nights of the grid and the Oregon star party and ran out used up all the gas in the generator and the 5 gallon gas can.

The next summer I upgraded the solar to 1440 watts plus 720 watts of portable solar and added 3 more 100 amp-hour BattleBorn batteries. I also replaced the Mach 3 13500 BTU air conditioner with a Mach 1 PowerSaver 11000 BTU air conditioner. The newer unit only pulls about 9.3 amps at 120 volts so it is much easier run all day when the sun shines. I run it on Cool Low Auto so the fan turns off when the compressor isn't running. The 700 amp-hours of batteries allow me to run the air conditioner to about 8 or 9PM for those running hot days. We tilt the 720 watts of portable solar panels in the direction of the low late afternoon sun.

We camp in the arid Great Basin so when don't need air conditioning once it cools off a few hours after sunset. We are usually camping at 5000 feet or higher. Our trailer is well insulated with slide outs so the 11000 BTU air conditioner can keep it comfortable on hot afternoons. A lot of hour camping is astronomy related so we are often camping away from shade trees which interfere with astronomy.

I stopped bringing the generator in the summer time for the air conditioner. I only use it for emergency power at my home when the power goes out.

[SiteTrek]

Originally Posted by rosebud1218

I see a "converter" in your drawing, but not an inverter, attached to your lithium battery bank. Given the microwave is the single electrical appliance will be drawing the most at 1200 watts, even running this for an hour consumes ~100 amps, leaving you with plenty of gas in the tank for other needs. The inverter will also consume power when in operation, but, again, you should have plenty with your 400 amp hours in the bank. Agree as well that with 1000W of solar, with your MPPT charge controller, ~3-4 hours of peak sun should provide you with a full charge, if starting at 50% discharge.

Seems like a robust and totally sane approach.

Good luck & safe travels!

I have an inverter that is factory installed in the coach that connects to the flooded batteries.

[SiteTrek]

Originally Posted by hamm2018

In September we added solar for our rig. We had installed 1600-watts of panels, 8-120AH Elevation brand batteries. We had 2–3000-watt inverters added, one to each leg of the breaker box. Plus, the other needed requirements for the system.
We have run 2 A/C units for 4 hours and did not run the generator.

You have a great system, that is out of my budget and we do not camp where it is hot ( just mainly winter months) so I never need the A/C

[SiteTrek]

Originally Posted by astrocamper

We bought our Artic Fox 22G trailer 2018. We started with 640 watts of solar on the roof and 4 100 amp-hour BattleBorn batteries. We used a Honda EU2200 when we wanted to use the air conditioner for which we installed an easy-start.

My wife complained about me running the generator too often because I liked using the air conditioner when it was hot. We spent 8 nights of the grid and the Oregon star party and ran out used up all the gas in the generator and the 5 gallon gas can.

The next summer I upgraded the solar to 1440 watts plus 720 watts of portable solar and added 3 more 100 amp-hour BattleBorn batteries. I also replaced the Mach 3 13500 BTU air conditioner with a Mach 1 PowerSaver 11000 BTU air conditioner. The newer unit only pulls about 9.3 amps at 120 volts so it is much easier run all day when the sun shines. I run it on Cool Low Auto so the fan turns off when the compressor isn't running. The 700 amp-hours of batteries allow me to run the air conditioner to about 8 or 9PM for those running hot days. We tilt the 720 watts of portable solar panels in the direction of the low late afternoon sun.

We camp in the arid Great Basin so when don't need air conditioning once it cools off a few hours after sunset. We are usually camping at 5000 feet or higher. Our trailer is well insulated with slide outs so the 11000 BTU air conditioner can keep it comfortable on hot afternoons. A lot of hour camping is astronomy related so we are often camping away from shade trees which interfere with astronomy.

I stopped bringing the generator in the summer time for the air conditioner. I only use it for emergency power at my home when the power goes out.

We only camp in the winter so I don't need the A/C. Last trip from 12-28 20 to 3-6-23, I never turned it on.

[astrocamper]

I have enough solar in that in the months when we don't run air conditioning, I use the inverter/charger to power the water heater when the sun is shinning. 700 amp-hours gives us several days of power even when running the furnace. The only time I don't get decent solar is when the panels are covered in snow. I avoid camping in the snow. I replaced the propane fridge with a 12 volt DC power fridge from Unique.

I only carry the portable panels when I know we will be using the air conditioning a lot when off grid. The 1440 watts of roof top solar keeps the batteries charged easily even in the seasons with lower sun and shorter days.

[Captain8]

I don't get your issues. Most inverters have option to change mode to lithium charging mode. The aux start issue depends on the battery BMS limit and if you have 2 or 4x then that limit is 2 or 4x, plus even if it's not enough the starter batteries also provide amps to help. The cold issue is easy to fix with 12v tank heaters on the batteries (you should also get these for your tanks). It's not much of an issue, for instance with mine at 32deg it stops charging and 0 degrees it stops discharging.


The issue is with lithium is your alternator as it can overcharge lithium since their charge voltage is lower.

I have 3000w solar, a Quattro 5000w inverter and 2x400a EG4-LL batteries. I disabled the connection to my alternator. Also put tank heaters on the batterys and I ended up putting the batteries and inverter in my bedroom. Ripped out my bedside table and put everything in there, the stock bay wasn't large enough to fit the batteries which is the only real reason.

[SiteTrek]

Originally Posted by Captain8

I don't get your issues. Most inverters have option to change mode to lithium charging mode. The aux start issue depends on the battery BMS limit and if you have 2 or 4x then that limit is 2 or 4x, plus even if it's not enough the starter batteries also provide amps to help. The cold issue is easy to fix with 12v tank heaters on the batteries (you should also get these for your tanks). It's not much of an issue, for instance with mine at 32deg it stops charging and 0 degrees it stops discharging.


The issue is with lithium is your alternator as it can overcharge lithium since their charge voltage is lower.

I have 3000w solar, a Quattro 5000w inverter and 2x400a EG4-LL batteries. I disabled the connection to my alternator. Also put tank heaters on the batterys and I ended up putting the batteries and inverter in my bedroom. Ripped out my bedside table and put everything in there, the stock bay wasn't large enough to fit the batteries which is the only real reason.

My issue is that that nothing in my current system on my motorhome is designed for lithium and it is easier to add a system than to adapt mine.

[Captain8]

Originally Posted by SiteTrek

My issue is that that nothing in my current system on my motorhome is designed for lithium and it is easier to add a system than to adapt mine.

What model inverter do you have? That's the only real issue is how the inverter charges the batteries

[SiteTrek]

Originally Posted by Captain8

What model inverter do you have? That's the only real issue is how the inverter charges the batteries

Magnetek 7300 and it will not work with lithium.
My BCC will not work with Lithium, nor if I replace the house batteries with lithium, they will not work in an emergency start situation.