Parallel/Serial - Excel V4.0 spreadsheet (Beginner question)

Good morning all,

I'm just starting out on my foray into solar and playing around with the v4 and looking at small systems. I think I'm being daft, but I don't understand the spreadsheet when it comes to parallel and serial strings, I'm only looking at a two panel system to start with but:

Going from one panel to two in parallel doubles the current as expected

Going from one panel to two in serial doubles the voltage and the current (?) Is this unexpected current increase because of how MPPT works as I'd expected voltage only to increase?

I hope I'm not missing something obvious

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Vance Mitchell commented · Jun 12, 2021 at 12:50 PM

When you are talking about current are you referring to panel current or battery current?

Panels in series will only have the current of a single panel but at a higher voltage.

The MPPT controller converts the high voltage/low current into a lower voltage/high current input into the batteries.

In an ideal world watts in would equal watts out but in reality there will be losses through the controller.

For example if you had 2 x 60w panels (20V 3A), series would be 40V 3A, parallel would be 20V 6A but both would supply 14.8V 7A (allowing 12% loss) to your battery.

There are plenty of articles already about choosing between series and parallel which will list the pros and cons for each.

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