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tyrosi asked

MPPT SmartSolar Disconnects via Relay

I’m using thee Victron SmartSolar MPPT charge controllers to charge my DIY LiFePO4 battery bank. I’d like to have my non-Victron BMS turn off the charge bus via a relay with contactor switch when it detects a high voltage limit with any of the cells. Can the SmartSolar charge controllers handle having the charge bus disconnected if it is in Float charge mode? If not, how can I automatically shut down the SmartSolar charge controllers when a high voltage limit is reached? Any suggestions would be greatly appreciated thank you.

MPPT Controllers
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Tom h answered ·
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tyrosi answered ·

Thank you for the reply. I don’t really understand this though. Does “Load output on/off normal This setting allows load output on/off control: (0V = switch load output off, +5V = switch load output on)” mean that if I have a relay send +5V will it tell the SmartSolar controller to enable charge output and when the circuit is opened (0V) will it turn off the charging?

What I’m also wondering is whether the SmartSolar chargers will be damaged if the charge bus gets disconnected while they are producing charge output?


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Tom h avatar image Tom h commented ·

"Load output on/off normal" - this is for controlling the load output of the charge controller, not the controller itself.

I think you would need to use this instead:

"Remote on/off (This is the default setting on all larger models). This setting allows remote on/off control: (Pin to GND = switch charger off, Pin floating or to battery+ (or a signal sent via VE.Direct communication) = switch charger on). An example of this operation is when the unit is connected to a VE.BUS BMS (using a VE.Direct non inverting remote on-off cable, ASS030550300)."



"What I’m also wondering is whether the SmartSolar chargers will be damaged if the charge bus gets disconnected while they are producing charge output?"

- From my experience, I think it is not a problem. For example if your main battery fuse blew or breaker disconnected I would not expect any damage to the charge controller.

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