diy solar

diy solar

Solar panels in parallel or in series for Bluetti AC200P?

Lots of misinformation in this thread, so I’ll try to help future noobs. I was here a few months ago asking similar questions, it’s time to give back.

1) what is overpanelling? When you have more total solar panel watts than what the charge controller can accept (700w). 701w wont blow it up. That guy was joking and is a salty hand around here. If you want to know how this black magic works, research MPPT charge controller.

2) is it safe to over panel? Yes, as long as the Voc limit (150volts) is not crossed. 151v will blow it up, but bluetti has put a “software” safety switch that seems to have worked for some of you. I dont know how it works with certainty, but I suspect it uses mosfets, so i wouldnt challenge it all the time, as the safety measure might fail.

Caveat: Dont rely on the voc written on the panel. That Voc is only at temp of 25C and goes up as it gets colder. Research this forum and do the math -or if you want to play it safe don't exceed 120v nominal (80%)
 
Caveat: Dont rely on the voc written on the panel. That Voc is only at temp of 25C and goes up as it gets colder. Research this forum and do the math -or if you want to play it safe don't exceed 120v nominal (80%)
Thank you for your contribution.

You say Voc goes up as it gets colder and 150V becomes 120V (or lower, as a"MisterSandals" believes).
So, one could add 2x solar panels Voc 42.9V in series? E.g. 2 x 42.9V = 85,8V ... but that number will be higher in winter. But less then 120V?
(each panel is 375W, Vmp 35.9V, Imp 10.56A)
 
You say Voc goes up as it gets colder and 150V becomes 120V (or lower, as a"MisterSandals" believes).
The Voc rating of panels is at standard temperature and conditions (STC). Usually 25°C.

All panels have a voltage-temperature coefficient telling you how much Voc changes per °C away from STC. Usually something like -0.3% per °C. Each panel should have this specification listed on its label.

So if the coldest temp your panel see is 0°C (32°F) then that is STC - 25°C, so you can expect the Voc to rise by -25°C x -0.3% / °C = 7.5%

If the Voc at STC is 42.9V, then at 0°C it will be 7.5% higher = 46.1V

If the temperature of the panels goes well below freezing, then you can expect Voc to be somewhat higher again.

Check the panel specifications and do the maths.
 
Yes.
People are using over 1000 watts of panels on the Bluetti AC200!
Why do so many noobs ask this question?

Yeah, 701 watts will blow up your AC200.
Kabooom!
I am using 3x385 watt panels in series. I’m good sun I actually see 700-800 input watts. Works fantastic
 
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