Nominal Output from 200W Solar?

[pteck]

Woohoo!!

Installing 200W of solar and just turned the system on for the first time. It's a Renology 2x 100W panels in parallel, with an EPEVER MPPT controller.

It's a bit overcast today, but I'm getting output. Shows 16V @ 6.5amp, or 104W on the PV input side. It's charging the batts 13.5V @ 7.5amps.

What are the nominal readings I should be expecting to see to assess health of the system? What kind of peak volts or amps should I see from the panels at mid-day? I get that it depends on panel alignment to the sun and I do not have perfect alignment as they sit relatively flat on the roof.

[uncle_bob]

Hi

Mounted flat in normal sunlight, you will never see more than 80% of the 200W. Your controller likely will knock another 5 to 10% off of that before you get to the battery. Part of that is wire loss which will not show up on the controller readout. What you are seeing sounds about right for an overcast day. You can have a 50% reduction in sunlight and still consider it to be moderate overcast.

Bob

[SCOTTinNJ]

I have 200w and that sounds about right. My biggest days are in the 550Wh range, so roughly 40 amps total.

Highest peaks are around 140-145w in bright sunshine.

[HiHoAgRV]

That performance sounds about right. I have 2x 100 renergy panels and unless the batteries are really low it runs in the 5-7 amps at 14.3 V in full sun.

[pteck]

Thanks guys, that helps a lot.

Also a great point about battery SOC. Am I right that the input/output of the controller is as much dependent on the SOC of the battery as the sun? So if the battery was say 80% full, the controller won't be maximizing the output of the panels?

[uncle_bob]

Originally Posted by pteck

Thanks guys, that helps a lot.

Also a great point about battery SOC. Am I right that the input/output of the controller is as much dependent on the SOC of the battery as the sun? So if the battery was say 80% full, the controller won't be maximizing the output of the panels?

Hi

Indeed, once the battery gets "full" the charger will cut back. Some of them "burp charge" the battery. They totally shut down for a while and then go full bore (where that's maybe 7A) rather than tapering back and running 1 or 2A forever and ever. Turn on some sort of load if you want to see what the "full output" of the charger is.

Bob