Author Topic: Wiring a battery bank  (Read 2506 times)

0 Members and 1 Guest are viewing this topic.

kittysmitty

  • Jr. Member
  • **
  • Posts: 52
Wiring a battery bank
« on: August 13, 2010, 11:29:25 AM »
I'm thinking about wiring up my batteries to a common buss bar. This should help with keeping the current draw even across all batteries.  If my inverter is fused for 200 AMPs, my inverter to buss bar wire size would be #2/0. My questions is, what size wire do I need from each battery to the buss bar. For example, ten, 12 volt batteries in parallel. Would the current draw from each battery be 20 amps? ( 200 amps total, divided by 10 batteries equals 20 amps per battery.)

DanG

  • Hero Member
  • *****
  • Posts: 1122
  • Country: us
  • 35 miles east of Lake Okeechobee

kittysmitty

  • Jr. Member
  • **
  • Posts: 52
Re: Wiring a battery bank
« Reply #2 on: August 14, 2010, 07:09:06 PM »
Let me state this a different way. If I'm drawing 200 amps from 10 batteries in parallel, am I drawing 20 amps from each battery?

Rover

  • Hero Member
  • *****
  • Posts: 788
Re: Wiring a battery bank
« Reply #3 on: August 15, 2010, 09:33:50 AM »
Theoretically yes.

Assuming all batteries the same type,capacity  , wire resitance the same etc
Rover
<Where did I bury that microcontroller?>

Ungrounded Lightning Rod

  • SuperHero Member
  • ******
  • Posts: 2866
Re: Wiring a battery bank
« Reply #4 on: August 15, 2010, 12:37:33 PM »
Let me state this a different way. If I'm drawing 200 amps from 10 batteries in parallel, am I drawing 20 amps from each battery?

As rover says:  Yes IF the wiring resistance matches.  Getting that to happen can be difficult, though.  It turns out that very small differences in wiring resistance can make considerable difference in battery balance during charge or discharge at nontrivial power.

If you're thinking "bus bars" you might want to just do "big terminal block" and have each battery wired separately to the block or a pair of big posts, with the sum of the lengths of the - and + cables the same for each battery.

If you want to jumper them to each other there are discussions on the board that you can hunt up telling how to do that while keeping the batteries  balanced.