# Battery Bank Wiring

Hi everyone! Thanks for your help with this.

I am writing a grant to fund the upgrade of a solar power system at a rural school in Uganda. I am currently in the process of accessing the state of the current system.

This is the only picture that I have of the battery bank.

I am attempting to determine how the batteries are currently configured, but this doesn't look like any of the diagrams I have come across. Has this bank been cross tied? Anything you can tell me about this picture would be extremely helpful.

Edit: They are sealed lead-acid 12V/200Ah batteries

Thank you

Allen

• Super Moderators Posts: 26,758 admin
Re: Battery Bank Wiring

What is the Inverter/Charger voltage? 12 or 24 volt DC... (I guess 60 VDC or 120 VDC is possible, but not standard or very common--at least around here).

I don't see any other practical working voltage with 10 batteries...

If 12 volts DC, then everything is connected in parallel.

If 24 VDC, then each pair of batteries is connected in series, then each pair (5 pairs) are connected in parallel.

-Bill
Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
• Solar Expert Posts: 10,311 ✭✭✭✭
Re: Battery Bank Wiring

as best as i can make out it would appear to be series/parallel 24v for a 5x2 configuration. they are also sealed and are possibly agm.
Re: Battery Bank Wiring

Bill: The charger is a Tristar 12Volt/60Amp TS-60MPPT and the inverter is a Phoenix Mult. C 24V/5000Watt.

Neil: I also though it was a 5x2 24 volt configuration but there seems to be too many cables.
• Solar Expert Posts: 1,959 ✭✭✭
Re: Battery Bank Wiring

The Tristar is 12/24/48V capable so go by the Inverter voltage which is 24V so Niel got it right
Re: Battery Bank Wiring

Can anyone tell from the picture if the bank if wired correctly for a 24 volt 5x2 configuration? The school has been having some problems with the system and I wouldn't be surprised to learn that the wiring is wrong.
• Solar Expert Posts: 1,959 ✭✭✭
Re: Battery Bank Wiring

Most "problems" are either to little charge or too much load. Also, even if a perfect balance, battery's have a finite life time.

Post the details of the charging source and the loads and i'm sure other will crunch the numbers for you

From the picture, it looks correct for a 5x2 configuration
Re: Battery Bank Wiring

It's a hybrid system that is charged by the panels and the powerline when it is on. The powerline is very unreliable though and I have been told is also at a much lower voltage then it is supposed to be. Here are the system specs:

(10) ASE Monocrystalline 150 Watt panels
(1) Tristar 12 Volt/60 Amp charge controller
(1) Phoenix Mult. C 24V/5000Watt inverter

Here is a picture I have of the charge controller and inverter.

The school is looking to at least double their current number of panels and batteries.
• Solar Expert Posts: 1,959 ✭✭✭
Re: Battery Bank Wiring

Sounds like either the battery's are getting old/abused or the loads are too high. 5000 watt inverter for that battery bank is MUCH to big

A good addition would be a battery monitor so the school could know when the battery bank has been depleted. I assume now, they run it until it cuts out on the low battery cutoff
• Solar Expert Posts: 7,249 ✭✭✭✭
Re: Battery Bank Wiring

I wonder if auto-EQ was disabled in the charge controller for Sealed batteries.

(Any idea if the batteries are AGM or GEL sealed) ?
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|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
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• Solar Expert Posts: 334 ✭✭✭✭✭✭
Re: Battery Bank Wiring
Sounds like either the battery's are getting old/abused or the loads are too high. 5000 watt inverter for that battery bank is MUCH to big

A good addition would be a battery monitor so the school could know when the battery bank has been depleted. I assume now, they run it until it cuts out on the low battery cutoff

I think that the OP meant that the grid power was unreliable and of lower voltage? I didn't catch that there was any problems that he is aware of yet...

5000 watt inverter doesn't sound so bad to me for a 1000AH 24V battery bank, if it's just being used as a back up and presumably not being run at full power all the time.

I'd second the recommendation of a battery monitor, and to start keeping some records of the system use and performance.