diy solar

diy solar

I need help understanding the amperage of my PV arrays

You are correct. I need 15a breakers. I can swap out the fuses for 15a for now. I am adding a combiner box once I get my new battery built. At that point all my breakers will be the correct 15a per string.

I see an issue with polarized breakers. Unless you can get non-polarized breakers, I suggest touch-safe fuse holders. After combining the strings, you can use a single breaker as a disconnect.

If once you install multiple inverters, no more than 2 PV strings go to any one MPPT input, fuses/breakers aren't required. Then even if you use polarized breakers as disconnect they (usually) won't have the issue that I'm aware of (or at least suspect). You can get some 4-gang polarized breakers from Schneider, rated for 250V when 2 poles are used. If you connect two strings through one ganged 4-pole breaker, that takes care of the concern I have with polarized breakers (so long as only 2 PV strings, no other on that MPPT input.)
 
I thought the pv had to be hooked up to get a reading. I've tried to prob a pv & nada. I'll play with it again.
Be careful if your panels have an amperage over 10A. Most DMMs are fused at 10A ... its a pita to buy and replace the fuses (not hard but a pita).
If you get a good voltage near Voc in full sun, call it a success.
 
Don't be like me and measure current from PV array by putting ammeter across the PV array while charge controller (capacitors) are also connected.

You can wire the meter in series with charge controller, close a switch, and measure what might be Imp (depending on battery SOC).
You can disconnect charge controller, wire a (suitably rated) switch and meter to measure short circuit current of PV panels. I set up a switch wired to my DMM so I can plug in PV panel, measure voltage, close switch, measure current. This avoids arcing in the connector.

You can use a DC breaker, even a polarized one, for the short circuit current tester. Just be sure to get the polarity correct!

My 10A DMM goes to 11! (amps fuse, that is)

You can also rotate a panel edgewise to the sun for zero amps while connecting meter. Watch amps rise as you turn back towards sun. If dealing with a high voltage series string, best to wire up and not try to probe unless you're brave (foolhardy) like me. And consider investing is shrouded safety banana plugs for the meter, which you could wire to MC connectors or switch.
 
I see an issue with polarized breakers. Unless you can get non-polarized breakers, I suggest touch-safe fuse holders. After combining the strings, you can use a single breaker as a disconnect.
I've got those jumbo style you find in cars. The combiner box I plan on getting. Once I have the correct battery.

If once you install multiple inverters, no more than 2 PV strings go to any one MPPT input, fuses/breakers aren't required.
Okay cool.

Be careful if your panels have an amperage over 10A. Most DMMs are fused at 10A ... its a pita to buy and replace the fuses (not hard but a pita).
If you get a good voltage near Voc in full sun, call it a success.
8.85a

Here's a little video I did on testing solar panels for the future.
Ha! I watched that about when it first came out. Glad for the refresh

And as always, remember:
Ah my dear Wattson



I had full sun today & charged to fill before noon. 41.8v to 46.8v in less than 3 hours. With the correct battery & wind I'll be gravy
 
Maximum power W 250
Open circuit voltage V 37.6
Voltage at pmax V 30.3
Short circuit current A 8.85
Current at pmax A 8.27
Max system voltage V 600
Fuse A 15

I've got 2x 6s pv arrays 1x 3s in parallel. East tilt 3s, summer tilt 6s, winter tilt 6s. All in parallel.

How is my amperage up to 58.02a? I should be under 30a according to how I thought series worked. The volts go up in series, the amps go up in parallel. Each series set should only be putting out 180v & 8.85a

I'm Cornfused af

Thanks guys for like the 17 thousandth time
I recently learned x voltage by 1.2 for cold sunny days .
 
I recently learned x voltage by 1.2 for cold sunny days .
I put my winter array at the furthest of all my arrays. I bet if I checked I'd be about right on 1. 30' of 10g is loosing a bit I believe.

Cold sunny days are the best. Cold being like 35F ish
 
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