Small Solar Panels - series or parallel ? (1 Viewer)

Nov 14, 2020
Funster No
Adria Compact SP
20 yr
I've had a little success with a small (40x20cm) panel, inside the van, located so it gets full sun over the whole panel. It seems to output 18/19v in good sunshine. It's intended to reduce need to drive van to charge batts.
(Adrian Flux just took extra £175 off me, for increasing annual mileage from 3000 to 5000 miles)

However, it is now connected direct to battery ( for only a couple of days at a time:= I'm keeping close watch on it ! )

I'm thinking of getting another of these, to sit in different sunlight footprint from other window, so that they generate enough juice for me to put them through the Victron MPPT.

Victron demands something like 5v more than batt V to start itself up (and allow power into batt). This means that if Batt SOC is 12v, it needs 17v from panel before it will even activate. If sun/pv output is bit weaker, the 17v threshold may not often be attained.

Question is: I'm assuming that if I put both panels in series to raise the voltage, it should energise the controller more readily (more often and/or longer periods).

But what would it do to the power from the panels - I'm assuming that raising the voltage would have some other effects ??



Oct 22, 2019
Funster No
2001 Pilote 270
Since 2004
Watts = volts x amps. In parallel you get double the current for the same voltage. Series is double voltage for the same current. Result in watts is the same. A common worry with panels in series is if one is in shade it affects both panels. So if you want to use two panels looking out of two different facing windows probably best to go for parallel. If both in the same window then series for earlier start. Best not to have panels inside a window though.

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