question

yelper avatar image
yelper asked

Series or parralell for solar panels onto 100/20

I have a 100/20 smart controller. I want to install 2 100w panels on the roof. I have 400ah of lithium...I know it's not enough but it's a start. My panel specs are

open circuit voltage 24.3v

Optimum voltage 20.3v

optimum current 4.93a

short circuit current 5.34a

max voltage 600vdc

The cabling is 10awg to a isolating 16a breaker then to the controller.

Which is the better way to connect?...in series or parallel? I'll likely add panels later.

Thanks




smart solar set-up help
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2 Answers
mariner avatar image
mariner answered ·

Run them in series, if you can. It doubles the voltage which means thinner wires needed and your solar performs better in lower lighting conditions (MPPT needing something like 5 volts over your battery to invert, series gives you double the surface area/voltage to achieve this).

Don’t run them in series if you’d go over the voltage max of the MPPT, which your current setup won’t.

Parallel set up is best if you know that your panels would experience different shading. Like one panel in full sun and the other 50% shaded.

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yelper avatar image yelper commented ·
Thanks very much. I got it up an running/charging.
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mariner avatar image
mariner answered ·

-and if you run it in series then your pre MPPT breaker may be over sized. A 7.5 amp breaker would do well.

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