question

sorin-t avatar image

Charging current advice needed

Hello,

I have a BlueSolar MPPT 100/30 charger and 2 used car batteries (12V, 60Ah), Varta, no maintenance needed (sealed), which I want to put in series so I can have a 24V system.

I see in VictronConnect that I can set the charging current .. but what value should I put there to be safe?

I plan in using the batteries mostly as a buffer system (a 24V, 300W pump is running to move the water from a deep well to a water tank).

Thank you!

chargingcurrent limit
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1 Answer
Stefanie avatar image
Stefanie answered ·

Hi @Sorin T.,

rule of thumb is 10-20% of the batteries capacity. So that's 6-12A max. charge current. But when in doubt, ask the manufacturer of your batteries.

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Hi @Stefanie

So considering they are in series, they are about 24v @ 60Ah so still 6-12A max charge current.

If I am to add another string of 2 batteries, this one in parallel with the other .. can I go to around 12-24A max charge? Right?

Thank you


PS: My panels are .. around 78V @ 20A max ratings (4 panels split in 2 strings of 2 x 2 (in parallel and series))

Yes, exactly. Once in parallel, the capacity doubles and you can charge at higher current ratings.

Thank you!