question

brasstacks avatar image
brasstacks asked

What charge controller for 2 panels and a 48V battery bank?

Looking to size a Victron Smartsolar Mppt controller to two LG 375 Watt panels in series, feeding a 48V lifepo4 battery bank bank.

RIght now my calculations tell me I need a 20 amp charge controller, however Victron does not make a 20 amp controller that supports a 48V battery bank.

Looks like Victron makes the MPPT 150/45-Tr amp but it does not look very common or available. the next up is the SmartSolar MPPT 150/60-Tr.

What would be the best smart controller to run this set up?

Thanks P


VictronConnect48v battery
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1 Answer
Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

The 100/20 is a 20A controller that supports 48V systems.

Though I am not sure what the open circuit voltage of your two LG panels in series is, perhaps over 100V in cold weather?

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brasstacks avatar image brasstacks commented ·

Guy

Thanks for making me aware that the 100/20 does support a 48 V battery bank.
The open circuit voltage on the LG 375 is 40.3 per panel so in series this is still below the 100v limit.
Are my calculations correct that I would need a 20A controller to run 2 x 375W panels connected to a 48V bank?
Thanks in advance.

P

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ brasstacks commented ·

That sounds fine from an ampere current sizing perspective.

I'd suggest to use this tool to confirm the low temp voltage - http://mppt.victronenergy.com

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brasstacks avatar image brasstacks Guy Stewart (Victron Community Manager) ♦♦ commented ·

Guy

Thanks for the calculator, seems the V temp. coeff and the I temp. coeff are not on my LG spec sheet unless it is names something else.

https://www.lg.com/us/business/neon%C2%AE-r/lg-lg375q1c-v5

Am I missing something or do I need to get these specs from LG to work it out.

Thanks for your assistance.

P

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