Battery voltage different in 24v setup

I have a 24v battery bank made up of 8 100ah Gell batteries. There are 2 banks of 4 batteries. The problem is that there is almost a full volt between the battery banks. 13.3v and 14.2v.
I am using the SRNE ML2440 charge controller. and 1000w of PV.
Any suggestions would be appreciated.
Ralph

rALPHBF said:

I have a 24v battery bank

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rALPHBF said:

almost a full volt between the battery banks. 13.3v and 14.2v

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Having trouble reconciling these two phrases. Please clarify.
Are these 6 volt batteries?

rALPHBF said:

I have a 24v battery bank made up of 8 100ah Gell batteries. There are 2 banks of 4 batteries. The problem is that there is almost a full volt between the battery banks. 13.3v and 14.2v.
I am using the SRNE ML2440 charge controller. and 1000w of PV.
Any suggestions would be appreciated.
Ralph

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Hello,
This is not healthy at all for your batteries. Check the voltage on each battery to clarify first there is no issue in one of the batteries. The second issue is to sketch how the batteries are connected together in series and in parallel and how they are connected to the charger.
Third point is to confirm that the cable size used to interconnect the batteries is the same.

TomC4306 said:

Having trouble reconciling these two phrases. Please clarify.
Are these 6 volt batteries?

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have a 24v battery bank made up of 8 100ah12v Gell batteries

tarek said:

Hello,
This is not healthy at all for your batteries. Check the voltage on each battery to clarify first there is no issue in one of the batteries. The second issue is to sketch how the batteries are connected together in series and in parallel and how they are connected to the charger.
Third point is to confirm that the cable size used to interconnect the batteries is the same.

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I have 2 rows of 4 batteries in parallel and those batteries are in series to make 24 volts.I believe the cable size is "0". Much bigger than the "4" that was recommended

Are they connected like Picture 1 or Picture 2?

Rednecktek said:

Are they connected like Picture 1 or Picture 2?

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no they are not. 2 sets of 4 batteries in parallel. .Those hooked up in series to make 24v.

Nope, look again, those are all parallel, each box is a bank (in your case 2x batteries in series). Point being that if they're connected up like Picture 1 the batteries at the far end aren't going to get as much charge as the batteries at the end with the charger attached and that will cause your batteries to be way out of whack over time.

If you've got them like Picture 1 and taking the positive from one end and the negative from the other it's better, but the batteries in the middle will still have the same starvation problems, just not as drastically.

If they're all going to a common point like Picture 2 then they should be staying balanced. If that's the case it might be bad cell time. They're Gel which means you can't check the water. You can try rotating your batteries around putting the dead-er ones closer to the charging terminals and see if they balance out, or pull them and throw each of the dead-er batteries on a charger to see if they'll top up and hold or not.

rALPHBF said:

no they are not. 2 sets of 4 batteries in parallel. .Those hooked up in series to make 24v.

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I suspect your battery balance is the result of improper wiring. Without a diagram or description of how they are wired it is hard to help diagnose this issue.

This basically my seTuP. I I have added 2 more batteries.

The wires from the charge CONTROLLER FEED IN ON THE BOTTOM RICHT AND THE TOP Right.

THE BATTERIES ON TOP ALL RUN 14.3V. tHE ONES ON THE BOTTOM RUN AT 13.3 VOLTS.

A LL BATTERIES ARE 3 MONTHS OLD AND ARE THE SAME IN EVERY ASPECT.

So all the current is flowing into the top batteries first, then going through the top 3 batteries before jumping down to the bottom 3 batteries?

Gotta be the most unique way of wiring up a 2s3p battery bank. I'm going to punt this one to @MisterSandals and @12VoltInstalls for clarification.

Rednecktek said:

So all the current is flowing into the top batteries first, then going through the top 3 batteries before jumping down to the bottom 3 batteries?

Gotta be the most unique way of wiring up a 2s3p battery bank. I'm going to punt this one to @MisterSandals and @12VoltInstalls for clarification.

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Ya, those aren’t balanced.
You can (and should) rewire to balance.

Assuming a 24V system you should have three pairs of 12V batteries, each pair being 12V times 2 = 24V. Then parallel them to a busbar with equal gauge equal length cables. Run the SCC output to the busbars.

There’s another way if you had 8 batteries but with six configured there’s no other way to cable them balanced.

I would fully charge each to its full capacity at 12V, let them sit unloaded uncharging for 4 hours, and test voltage. Pair them to be each as close as possible in static/nominal voltage, and recable with identical gauge and length cables.

12VoltInstalls said:

Ya, those aren’t balanced.
You can (and should) rewire to balance.

Assuming a 24V system you should have three pairs of 12V batteries, each pair being 12V times 2 = 24V. Then parallel them to a busbar with equal gauge equal length cables. Run the SCC output to the busbars.

There’s another way if you had 8 batteries but with six configured there’s no other way to cable them balanced.

I would fully charge each to its full capacity at 12V, let them sit unloaded uncharging for 4 hours, and test voltage. Pair them to be each as close as possible in static/nominal voltage, and recable with identical gauge and length cables.

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The picture is about 2 weeks old, I now have 8 batteries and in a few weeks I will have 10 batteries.
I'm thinking 5 groups of two with charging wires on each group.
I will charge the batteries tomorrow and let them rest for the 4 hours

Rednecktek said:

So all the current is flowing into the top batteries first, then going through the top 3 batteries before jumping down to the bottom 3 batteries?

Gotta be the most unique way of wiring up a 2s3p battery bank. I'm going to punt this one to @MisterSandals and @12VoltInstalls for clarification.

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What is so unusual about it?

rALPHBF said:

5 groups of two with charging wires on each group

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That will work for ten
2, 4, 8 and 12 are simpler to deal with.

rALPHBF said:

will charge the batteries tomorrow and let them rest for the 4 hours

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Each one should be charged to same voltage then rested for “settled” voltage

I heard back from my charge controller Manuf. SRNE today.
They SAID IT WAS NORMAL.
So my first mistake was buying a SRNE product.