Two panels fitted at different angles on van roof?

[jp11]

I'm contemplating fitting two 175w Renogy flexibles on the roof of my high-roof Mk8 Transit. This van has a large sloping section to the front of the roof above the windscreen (sorry, I'm from Ireland), windshield if you like. This to make use of low sun angle when parked (we have a lot of low sun here!, and very often no sun).
This may produce differing outputs from both panels. Will that be an issue?

[bcroe]

You may connect them in parallel since the voltage varies little with sun intensity.
Series NO, since they will usually produce different currents. Bruce Roe

[jp11]

OK Bruce, yes I would have them in parallel. So I guess they'd simply be producing different wattage?

[bcroe]

Watt = V x A, so different amps (depending on sun) will give different wattage. Bruce Roe

[jp11]

Ah, thanks Bruce. Of course, a light bulb moment for me. The panels produce current, not watts. Watts are what we consume?

[Weldman]

And of the two panels the one producing the most wattage/amps will be dragged down by the one getting the least amount.

[bcroe]

And of the two panels the one producing the most wattage/amps will be dragged down by the one getting the least amount.

If you mean best sun panel voltage dragged down when in parallel, does not happen.
The best sun panel is operated about 80% of open circuit voltage for the most power.
The poor sun panel will also try to reach open circuit voltage, but when it hits the 80%
value, it will contribute its minimal output current to the load. Neither panel takes
power from the other. If they could, practice would be to include blocking diodes, but
that is not required. Bruce Roe

[Mike90250]

If you mean best sun panel voltage dragged down when in parallel, does not happen.
The best sun panel is operated about 80% of open circuit voltage for the most power.
The poor sun panel will also try to reach open circuit voltage, but when it hits the 80%
value, it will contribute its minimal output current to the load. Neither panel takes
power from the other. If they could, practice would be to include blocking diodes, but
that is not required. Bruce Roe

This is true when both panels have similar Vmp. ( another thread has a poster with a ~250W panel & ~80W panel, which are not likely to match well

[bcroe]

This is true when both panels have similar Vmp. ( another thread has a poster with a ~250W panel & ~80W panel, which are not likely to match well

Yes, the beginning post stated 2 apparently identical panels. To match up operating
voltage, I go more by the number of cells, than the single point published Vmp. Here
a string of 10 each 72 cell panels is paralleled with a string of 12 each 60 cell panels.
Bruce Roe

[jp11]

So are we saying that there is no benefit in mounting one of the two identical panels at a different angle?

[bcroe]

So are we saying that there is no benefit in mounting one
of the two identical panels at a different angle?

That is too simplistic a statement. I have panels mounted at 3 different orientations
and 3 different angles, driven by things like my inverter sizes, net metering agreement,
and the frequent clouds. What works for me is not optimized for you. Bruce Roe