question

jrpatroller avatar image
jrpatroller asked

Why are my batteries discharging unequally?

3 206ah heated SOK Batteries connected to Lynx Power In

All battery cables of exactly same length

Power In connected to Lynx Shunt

Lynx Shunt connected to Lynx Distributor

Aims 3000W inverter charger connected to Lynx Distributor

Batteries discharge relative to position on Lynx Power In. Small system and only one and at times 2 batteries discharge at all while 3rd battery rarely falls below 100%


lynx shuntlynx distributor
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Trevor Bird avatar image Trevor Bird commented ·
@jrpatroller@gmail.com what happens when they discharge to say, 50% SOC?
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2 Answers
snoobler avatar image
snoobler answered ·

Are your batteries properly wired?

All connections properly torqued?

"Small system"? How small? What current?

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Sarah avatar image
Sarah answered ·

Hi @jrpatroller some trouble shooting might be in order.

- Have the batteries been through the necessary 2 complete charge / discharge cycles to synchronise the State of Charge?

https://www.us.sokbattery.com/product-page/sok-12v-206ah-lifepo4-battery-bluetooth-built-in-heater

Do this to each battery independently of the others.

- How does each battery perform when they are individually connected?

- What happens when all of the batteries are connected and you swap the first and third one over.

- Given that the batteries all have their own individual BMS are these configured identically and are the batteries the same temperature?

Hope this helps.

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jrpatroller avatar image jrpatroller commented ·
thanks for the reply! I am very new to solar and kind of inherited this system, so please forgive my ignorance.

The system has NOT been through a complete discharge cycle. It is in a small off grid cabin that is only in use 3-5 days a month. The "lowest" battery soc that I've seen is 65%, second battery mid 80% and third battery doesn't come much off 100% by the time I leave. 800W of solar charge the batteries during the stay and by the time of the next visit all batteries are back up to 100%. Small 12V refrigerator (wired directly to Lynx Distributor), 110V water pump/very minimal use, and 4 LED lights through Aims Inverter - so not much load.

I could certainly turn off panels to discharge the batteries if that is what is needed. If you have any other suggestions I am willing to try them. I just don't want to damage the batteries.

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Sarah avatar image Sarah jrpatroller commented ·
The link I provided will take you to the battery manual. Check the install procedures in the manual for discharging the batteries.

Running one battery at a time will also confirm if you have any problems with the batteries.

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kevgermany avatar image kevgermany ♦♦ Sarah commented ·
@jrpatroller
Also worth checking the quality of the battery to lynx power in connections. Maybe some grease/oil in the connections.
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