Best Arrangement for Batteries & Inverter

[JaimesBeam]

So, I got four Valence U1-12RT U-Charge Lithium Batteries that I got cheap.
12.8V, 40 Ah, 512 Wh. Max Input 14.6V. I have a PowerMax 1000W Pure Sine Inverter. I made some 1 ft long 6 AWG cables. I had planned to mount the Batteries under the bed, and hang the Inverter on the cabinet wall next to them. The batteries are 5" x8".

I'm wondering what's the best way to place the batteries to get as many as possible to hook up with 1 ft cables in a 'star' configuration with each set of cables going from each battery to the inverter, or to some disconnect/ breaker/ etc.. Should I put them long side or short side toward the inverter? Some other arrangement? I'll probably sooner or later get more batteries. I have some heavier cables and a buss bar if I need it. I wonder if I can bolt the Buss bars
down alongside the batteries on each side and strap them down from there...

I planned on bolting a piece of 3/4" plywood, say 18" x 18" to the floor, and then strapping the batteries down to the plywood. Does Harbor Freight of some other place have good material for strapping the batteries down?

I'm kind of winging this initial setup. I imagine I'll modify it or upgrade it soon, but I'd like to have something for a holiday trip.

[jcussen]

Looks good.
https://www.wirebarn.com/Wire-Calculator-_ep_41.html

[NewBlackDak]

If you really intend to add more, I would just start with a buss bar. No sense in having to redo work later for something you already know is coming.

[jcussen]

Agree with bus bars, I started with 2 batteries and expanded to 6. When adding new batteries, just add equal length cables from batteries to busbar, that way equal resistance and load on each battery.

[phfkef]

Remember the more power that you produce ( battery and inverter), the more heat produced. If possible, it would be good to provide an air vent to the space under your bed.

[JaimesBeam]

One thing: because of tge shape on the batteries, with indented terminals, there is no way to have a literal bus at, a bar you fasten down the the battery terminals. How do you deal with that?

[NewBlackDak]

Originally Posted by JaimesBeam

One thing: because of tge shape on the batteries, with indented terminals, there is no way to have a literal bus at, a bar you fasten down the the battery terminals. How do you deal with that?

Short, thick, equal length cables from the terminals to the bar.

[JaimesBeam]

Yeah, I figured going with a bunch of 18” 6 gauge wires going from each battery to the inverter input. But I should have a shut off in there somewhere.

[Mark_K5LXP]

Bus bars aren't usually used for vehicular battery connections due to the stresses of vibration and movement on the terminals. Not sure how the terminals of these lithiums are configured so maybe it's a non problem. Practically speaking cables give more orientation options and at this level of power I wouldn't worry too much about losses using an appropriate wire gauge.

Mark B.
Albuquerque, NM

[JaimesBeam]

There is a picture of the batteries earlier in the topic.

[NewBlackDak]

Originally Posted by Mark_K5LXP

Bus bars aren't usually used for vehicular battery connections due to the stresses of vibration and movement on the terminals. Not sure how the terminals of these lithiums are configured so maybe it's a non problem. Practically speaking cables give more orientation options and at this level of power I wouldn't worry too much about losses using an appropriate wire gauge.

Mark B.
Albuquerque, NM

It’s probably more appropriately called a power distribution block, but it serves the same purpose.

[JaimesBeam]

So it seems my diesel has two alternators. I don’t know where to pick up the power to charge my batteries. There are a couple of busses in the electrical cabinet... do I need a battery select switch, circuit breaker/disconnect switch, or something smarter to limit the load/draw?

Kind of a duplicate question, but I wanted to put it here as well...

[twinboat]

You buy a battery to battery charger and connect it to the chassis battery and your new batteries.

Your alternators don't have the proper charging voltages for lithium.

[JaimesBeam]

The Valence U1-12RT are made to be charged with a standard GEL/AGM Battery charger. The full specs are at the link below. They shouldn't need a special charger.

Valence U1-12RT U-Charge Lithium LFMP Batteries
12.8V, 40 Ah, 512 Wh. Max Input 14.6V.

http://elbil.pbworks.com/f/U-Charge+RT+Data+Sheet.pdf