question

John Frame avatar image
John Frame asked

How do I limit my SmartSolar charge controller to charging my battery bank at 99%

Here are some details of my system.
I have two SmartSolar charge controllers feeding one DIY battery.

Charge controller 1
SmartSolar 150/45 - Fed by a 1200 watt array on the roof of the camper.

Charge controller 2
SmartSolar 100/30 - Fed by a 500 watt ground deploy array

Battery Bank
6014 wh DIY battery - 24 volts
8S - Daly 250 amp BMS

I am getting a "Cell volt high level 2" fault alarm on the daly BMS.
The BMS turns off charging when this happens but otherwise is operating normally and once the charging backs off due to a load being put on the battery the fault clears and charging resumes.

The BMS cell voltage limit is set to 3.65 and the "Sum volt high protect" is set to 29.2.d
So it would seem the charge voltage from the Smart Solar charge controllers is exceeding the limit.
When only one charge controller is connected this doesn't happen.

But if I have used a lot of power overnight for some reason and I deploy the ground array to charge faster then once it reaches absorption I get the "Cel volt hight level 2" Fault.

((((MY QUESTION))))
My question is can I tell one of the SmartSolar charge controller to stop charging at 99% so that it won't exceed the voltage limit? Should I set the float voltage lower? It is set to 27.00 volts now.
Or should I set the absorption voltage lower? It is set to 28.4.

@Guy Stewart (Victron Community Manager)

smart solar charging behaviour
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1 Answer
Paul B avatar image
Paul B answered ·

My gues is that your battery is NOT balanced the Daly units only have a cell balancing current of 0.035amps ( close to useless in my opinion) the over voltage warning you will be getting is more than likley a cell hi voltage on one of the cells . to fix this get a BMS that balances at 1 amp or more ie the 123smart BMS- The daly will do it but it will take months depending on the out of balance size. ie the daly is 0.035amps most others are 1.000 amps or more so there is a BIG difference in there balancing power.

the smatsolar does not go by SOC so reduce the charge bulk/Absorbstion voltage from 14.2 to say 13.9 this will reduce the charge level

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