question

mariner avatar image
mariner asked

Possible Reverse Current through SBP using MPPTs

God Day,


I am using a SBP 220 in line from my charging components to the LiFePo4 housing bank, three MPPTs and two Orions. Wired where the charge goes to the “In” and then the “Out” goes to the house bank.

The two thoughts I have on reverse current is:

1. When there’s no solar the MPPTs draw power from the battery bank to remain On. I’ve read this is such a little draw that the SBP is able to handle this due to dissipating heat. Even though everywhere in big bold letters we are told No reverse current from Victron. Yet they’ll show this same setup on their diagrams. With this being said, how much is too much? Could three MPPTs end up being too many? What about a fourth, or adding two Orions? All very little standby draw but still adds up, right?

2. Continuing that thought, what about the streetlight function on the MPPTs? Granted, I’m still trying to learn how that works but seems like the MPPT controls the Streetlight function through the means of a relay? Would that then draw power from the battery to operate the relay or signal it sends, in turn drawing power from the bank and through the SBP adding to the reverse current?

Just hoping to achieve a more accurate idea of what’s acceptable than my “should be good” current state of thought. Not trying to break an SBP or worse, start a fire on the boat or something.

MPPT ControllersBattery Protect
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2 Answers
Paul B avatar image
Paul B answered ·

As long as the reverse current was UNDER 5 amps (the lower the better) as a guess there would be no issue, the amps required to keep a MPP on is very small

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mariner avatar image
mariner answered ·

Any comment about the streetlight function and what it may draw/if that draws through the SBP?

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