Using a lithium battery as a house battery in an overland vehicle

[jscherb]

Welcome back! Hope your move went smoothly.

Haven't moved yet. We took possession of the house in mid-January and since then I've been spending about half time there doing maintenance and upgrades, and designing a garage addition. Every trip I tow a trailer full of stuff, so I've moved quite a bit but there's lots still in the NY house.



I've been downsizing a lot of stuff, got rid of many molds I don't plan to use again and making plans to set up my workshop in an existing two-car garage but probably won't complete the move until we sell the NY house, which will go on the market in May.

And speaking of downsizing, I plan to sell my plow - I don't expect to need it as much in Delaware as I -have in upstate NY. I'll probably list it locally in the next couple of weeks, looking to get $500 for it.

 

[jscherb]

Hey Jeff,
If you're going to upgrade your charging system, check this out

RENOGY 12V/24V IP67 50A DC-DC Battery Charger with MPPT

Renogy offers reliable and innovative solar panels, inverters, lithium batteries, and solar charge controller for off-grid solar systems. Shop confidently with premium-quality products, expert guidance, and outstanding customer care to achieve your energy goals with ease.

www.renogy.com

It's a dual charger (DC-DC & Solar) that does everything you want.
I'm actually installing it in my Africa Jeep right now to ugrade the very outdated system. I'll have a video review out shortly.

-Dan

Dan,
Thanks, I have looked at that one. I like that it has a 50amp charge rate and handles solar as well. It's something I'll consider, although my existing lead-acid battery and wiring has been working great for years so I haven't decided for sure if I'm going to upgrade to lithium or if I'll just leave the lithium powering the backup sump pump in the house .

 

[rruff]

It's unlikely that 16-gauge wire will deliver the necessary voltage and current to the charge controller for it to provide its full output to the battery but the specs of the specific charge controller chosen will have to be checked to see what it needs as its input to provide full output.

Exactly... but you were talking about 2-gauge wire, and that's a lot more stout than necessary. Just need to work the numbers, and size the wires for a modest loss. The Renogy charger needs 8V minimum, so no worries there.

 

[jscherb]

Exactly... but you were talking about 2-gauge wire, and that's a lot more stout than necessary. Just need to work the numbers, and size the wires for a modest loss. The Renogy charger needs 8V minimum, so no worries there.

Agreed. My calculations for 2-gauge copper were to provide 14.4 volts at 20 amps to the battery at the back of the Jeep, supplied by the alternator, which would be enough to charge the lithium battery fully, albeit not with the recommended charging profile. The voltage drop of my current 2 gauge CCA wire only results in about 13.5 volts, which is plenty to charge a lead acid but not adequate for a lithium.

One thing to keep in mind when calculating the wire gauge and voltage drop if you're using something like the Renogy is that power output has a direct relationship to the input voltage and current: P=EI (power = voltage * current ). So if you calculate your wire to provide the Renogy with 10 volts at 20 amps, the math works out to 10 * 20 = 14.4 * X, where X will be the theoretical maximum output current of the Renogy given that the Renogy will output 14.4 volts to charge the lithium battery. The equation with these numbers works out to 13.9 amps, which is short of the Renogy's advertised 20 amp output (assuming it's a 20 amp Renogy, they make units with different ratings).

 

[Jupiter58]

Always great detail and well written posts!
Very interesting and thanks for sharing jcsherb!

 

[Peter_n_Margaret]

I am about to install this in our expedition vehicle.
It weighs a tad under 30kgs and will replace 400Ah of AGMs that weights over 120kgs.
LiFeO4 is the safest of all the various lithium ion battery chemistries.

CALB 12V 326Ah Lithium Battery & 250A Daly Smart BMS

CALB 12V 326Ah Lithium Battery & 250A Daly Smart BMS - Assembled in Australia 300Ah

www.solar4rvs.com.au

Our new build truck will get something similar, but larger capacity. The house will be all electric (and a little diesel), no LPG, 2kW+ solar.
Cheers,
Peter
OKA196 motorhome

 

[nwoods]

The house battery is carried in a tray over the inner rear fender; in the '13 JKU, the tray is a MORryde ammo can/battery tray (https://www.morryde.com/products/ammo-can-battery-tray-kit-with-molle-holder/); there's a cover made from soft top fabric with MOLLE attachments on it for accessories:

Jay, I thank you for your endless creativity and innovation on making practical ideals come to fruition. That MOLLE panel shelf unit was a bit pricey for me, but I was inspired by it and give you direct credit for what I came up with. I needed a place to store a 3 gallon Dometic water tank in my Jeep, and this worked out great: