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Duncan avatar image
Duncan asked

One PV panel: two MPPT and two batteries

Hi

I read an answer to a quite similar question but my setup may be a little different.

I have a [single PV array]—[isolation switch]—[terminal block]—[MPPT 75/15]—[battery]

I now have a portable power station with onboard MPPT.

I have joined the PPS DC input at the terminal block so it is in parallel with the MPPT 75/15.

Before attaching the DC input to PPS, I turned off the MPPT 75/15 in the Victron app.

Q1 In this situation are the batteries in the two systems physically connected, and is this a problem as the MPPT input cables are connected in parallel?

Q2 If the MPPT 75/15 was switched back on while the PPS was charging what would happen? Hoping they would work harmoniously and share the PV ououts but also think it is possible that current could flow directly between each battery unless there were reverse current protection diodes in the MPPTs


No problem manually switching, but somewhat easier if they work together

Thanks?

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2 Answers
nickdb avatar image
nickdb answered ·

You cannot share pv across mppts, this is documented.

The chargers will conflict and not be able to track properly.

Plenty of posts on this very topic available via a search.


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Duncan avatar image Duncan commented ·

Software disabling of the Victron charger is OK though? I expect so, the power MOSFETs would be closed, but confirmation would be good.

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kevgermany avatar image
kevgermany answered ·

Does your power station have a 12V input? If so connect this, not the PV input, to the MPPT output.

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Duncan avatar image Duncan commented ·

That is an idea. Hadn’t thought about that as was only focussing on using that mode in the vehicle. Uses the same input socket as the solar (500W) but the 12V current must be regulated to around 100W so will be a bit more that half as fast as directly from the solar panels.p when the sun is out

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