Wiring panels in series that are a different size

[eraser1]

If you wire a 165 watt 24volt panel in series with a 175watt 24volt panel

the output I think will be 28 volts @ 165 watts , because the smaller panel reduces the output of the larger one is this correct.

If this is the case If i had the 165watt panel and wired it parallel with a 10 watt panel , than wired this in series with the 175watt panel would my out put be 48 volts@175 watts???

I am asking this as i have a few odd panels around and want to wire them up to a grid inverter which has a 48 volt input.

[AbyssUnderground]

For series the maximum power going through the string is the maximum power of the lowest power panel.

So, 10w panel plus 165w panel in series equals 10w output only.

[Darren73]

Eraser,

Yes you are correct, I'm assuming that the 28V is a typo and you meant 48V though.

Regards

Darren

[maker of toys]

yes and no.

watts is a power measure;  connecting up a set of panels in series will result (assuming reasonable matching of output parameters) in greater output power than either panel can achieve alone.

the question makes more sense if you ask about the output current; but you are correct in thinking that the panel with the lowest output current sets the limit for the entire series array.

In your case, connecting the 175W and the 165 W panel would give an array of about 330W at 48V. in reality, even discounting all the weather and loading curve fudge-factors,  you'll achieve somewhat less, becasue some of the 'lost' power from the bigger panel will heat up the smaller one, reducing its efficiency. I can't tell you qualitatively how much effect you'll actually see without knowing a lot more than I do about your panels. . . .  and even then it'd be a guess.

I'm not sure that adding the 10W panel will ensure perfect matching with the 175W panel (too many variables unaccounted for) but it can't hurt.

[Nando]

Wiring panels in series where one may have different current, the overall system current will be the one with the least current.

The internal dissipation may be equal, since one is less loaded.

Do not work based on watts, work based on current and volts.

To parallel panels, both can have different current capacity but to insure equal loading, the Voc and Vmp of each panel should be close to each other, other wise there is a power unbalanced that may not be apparent unless individual current measurements are made under the same solar flux.

This reasoning was used when some large panels systems were implemented to attain the highest possible MPPT currents.

Nando

[wooferhound]

Yes, you are correct

one 10watt and one 165watt in parallel is 175watts

put that in series with your 175 watt panel

and you will get the full 175 watts out while doubling the voltage.

[nick1234]

panels like batteries in series voltages add current is always the lowest unit

in parallel curents add   voltage say the same do not mix voltages in paralellel

nick1234

[Rewop Emoh]

Double the voltage same amperage double the wattage. 48v 350 watt same 7.3 amps.

[tecker]

Alot depends on how they perform in the sun .I'm guessing the 10 watt is an amorphous panel They don't track the same under load they might give you some extra power in parallel .You have to measure them in the sun under load .