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Old Seagull Man
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Joined: 21/12/2019
Location: Australia
Posts: 55

Posted: 11:22am 15 Oct 2020

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my neighbor has a small battery bank on hobby farm.

Its consists 8 trojan t105 batteries. all new.
But he finds that when he charges them up, the first and the last battery, as he put it dont have any go.

So i dropped in on the weekend and checked all the wiring and the settings on the charge controller. all as the manual says they should be.

So checked the specific gravity of all the batteries and shore enough, battery 1 and battery 8 were around 1.12 and 6.12 volts all the other batteries around, 1.26 and 6.5 volts. i have suggested he swap the order of the battery's, and try again. and see what happens.

Any ideas?

Solar Mike
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Joined: 08/02/2015
Location: New Zealand
Posts: 1138

Posted: 11:39am 15 Oct 2020

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Sometimes the end batteries run slightly cooler and this will affect their charging, relative to the others. If the 8 batteries are bumping up against each other the inner ones have less surface area to dissipate heat.

Try placing them in a rack off the ground with an air gap between them, so they all get good air flow for equal cooling. Also make sure your charger has a battery temperature sensor, so they get the correct charge rate.

Cheers
Mike

Warpspeed
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Joined: 09/08/2007
Location: Australia
Posts: 4406

Posted: 07:28pm 15 Oct 2020

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Excellent advice Mike.
If an off the ground rack is just not possible, at least sit each battery on a thick piece of wood so its not in direct thermal contact with soil or concrete.

Cheers, �Tony.

Old Seagull Man
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Joined: 21/12/2019
Location: Australia
Posts: 55

Posted: 02:04pm 16 Oct 2020

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Thanks for the thoughts guys.

The battery's sit on steel shelving inside a large shed.
And have the controllers temp probe connected to the case of the third battery in the set.

All the joining cables are the same length and same cable.

Next time i visit i will take a 12v charger and see if i can get the odd two to charge.
As i don't have a 6 volt charge to do them one at a time.

So no luck so far

Revlac

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Joined: 31/12/2016
Location: Australia
Posts: 1022

Posted: 02:30am 17 Oct 2020

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I had a similar situation once, 4 12v batteries on a 48v system and 2 of them were low.
An easy fix, was to connect a car head light on each of those that were high, just to knock the voltage down a little, the charge controller would then push the other 2 up, did this for a day and its been good ever since.

It was easy me to do that than lug the Heavy charger up to the shed.

Cheers Aaron
Off The Grid

pollenface

Regular Member

Joined: 01/09/2020
Location: Australia
Posts: 47

Posted: 11:10am 29 Oct 2020

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I run a balancer on my 24v bank.

Prior to having the balancer, the positive side would always be higher when charging and the negative side lower when discharging.

Off grid man caver

Old Seagull Man
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Joined: 21/12/2019
Location: Australia
Posts: 55

Posted: 11:32pm 29 Oct 2020

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Thanks pollenface.

Tell me about your balancer Please

pollenface

Regular Member

Joined: 01/09/2020
Location: Australia
Posts: 47

Posted: 11:33am 30 Oct 2020

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It's just an ebay jobbie, but it works.
https://www.google.com/search?client=firefox-b-d&q=ha01+battery+balancer
Edited 2020-10-30 21:34 by pollenface

Off grid man caver

nickskethisniks
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Joined: 17/10/2017
Location: Belgium
Posts: 458

Posted: 09:53pm 30 Oct 2020

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I'm using this type of active balancer but the 48V type (4batteries). It's in service for over a year now and it's doing a good job.I'm running this on a 900Ah (400Ah AGM and 500Ah lifepo4) In theory, because it's an old battery pack, and heavely out balance so it's having a hard live.
The only problem I have is that it's making a high pitch noise, just below the 20khz I think.
I'm testing my own activebalancers last version at the moment with good results, but I'm missing spare time to finish them for 100%. It can be found somewhere on this forum.

balancer
Edited 2020-10-31 07:56 by nickskethisniks

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