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sailinganuri avatar image
sailinganuri asked

Battery charging issue 24 volt system

We just installed six 12 volt lithium batteries 200(ah) in series (24v) and then in parallel. There seems to be a problem during the charging phase as only one battery in each of the series is charging to 14.8 volts or higher while the other battery in the series is slowly charging at 13.5 with none getting to the 14 volt stage. Do we need a battery balancer? Also two of the batteries in the series that is getting the higher voltage is connected to the positive while the third one is connected to the negative.

battery chargingLithium Battery
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gro avatar image
gro answered ·

Charge all your batteries before connecting in series. If only one battery in a string charges up to 14.8 V, it means that battery had more charge at the start of the charging while in series. Take all your batteries and place them in parallel on a charger, or do them one at a time. Just make sure you top balance the packs before connecting them in series.

You could just change the pairings so the lower voltage batteries are placed in a string and continue to charge. Once they are all charged up to the same level and paired up they should stay fairly well balanced.


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coyoteandlizard avatar image
coyoteandlizard answered ·

parallel-wiring-for-battery-banks-24v.pngDid you connect your main positive and negative on opposite positions on your battery bank? If not this is likely the source of your issue. Also make sure all of your connections are clean and using properly sized connectors. Be sure all of your wires are the same type and size.


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Rob Fijn avatar image
Rob Fijn answered ·

Interesting.. What kind of batteries you have?
Can you send a picture ?
Regards, Rob

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kevgermany avatar image
kevgermany answered ·

Balancer will balance between the members of the 24V battery sets. So for your setup you'd need three. You can download the Victron datasheet for the balancer from the victron Website. It shows the correct wiring for batteries and balancers including setups like yours.

If you're wired as above, check your cables for resistance and battery connections for tightness.

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mats avatar image mats commented ·

according to Wiring-Unlimited-EN.pdf (victronenergy.com) page 21-22 you can connect the midpoints from the different strings and use a single balancer

I believe you should manually balance them before connecting the midpoints

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sailinganuri avatar image
sailinganuri answered ·

Here is a photo of our setup without the starter battery in place. We did charge all the batteries prior to installing and it seems that this morning after using the batteries without charging and then charging them again, most charged similarly except for two.01f09ead-4030-4318-8a55-b0ffe96f92ab-1-105-c.jpeg


01f09ead-4030-4318-8a55-b0ffe96f92ab-1-105-c.jpeg (311.1 KiB)
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