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goodsellrod avatar image
goodsellrod asked

over voltage

I am a new solar user with a new system, I am getting a high voltage alarm from the cerbo and the batteries confirm there are multiple high voltage protects enabled, 191 times. the problem is occurring when the batteries are at 100%. the system starts doing a push pull effect on the batteries, every couple seconds it changes from charge to discharge and then ends up in a overcharge. I have 2200 watts of solar peak. it's pushing 200 volts to the MPPT 250/60 which is charging two 48v SOK server rack batteries. the batteries are connected to a MultiPlus-ll 48-3000-35.right now I am having disconnect the pv input when the batteries are full to stop the overcharge. help please:-)


charge current limit
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jessiejim1 avatar image
jessiejim1 answered ·

You can adjust the charging settings on your MPPT 250/60, so that it does not push as much voltage to the batteries when they are already at 100%. You could also consider adding additional batteries to your system, which would allow for more energy storage capacity and help prevent overcharging.

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goodsellrod avatar image goodsellrod commented ·
what setting would adjust the charge current when it reaches 100%. I don't understand the modulating back and forth from charge to discharge when the batteries are full and there is AC current being inverted. if I am using 6 or 700 watts of AC shouldn't the pv be able to provide that and just leave the batteries at 100%?
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kevgermany avatar image
kevgermany answered ·

What are your MPPT battery settings? Are these the same as the battery maker values? Are these lithium batteries?

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goodsellrod avatar image goodsellrod commented ·
yes it appears that the MPPT voltage settings are correct and yes the batteries are lithium. battery charge setting set @60 amps, battery mfr recommends 63 amps, absorption voltage @57.6, float voltage @55.2 as recommended
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derrick thomas answered ·

You might look into node red. You could create a flow to pull back on the maximum allowed charging current as you get near the abs voltage. You could do it in steps.

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