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diy solar

Measuring Current From Panels

OMG this is a mess

I think you don't quite understand how current from PV / amperage testing works.
Your current set up might be capable of putting out 45 amps but it isn't. (assuming you're using the clamp meter correctly)

There are multiple reasons why you might not getting full output from this solar set up.
To test for full possible amps from the array: disconnect PV wires from charge controller, short PV+ and PV- together, measure amperage.

There's no other proper way to get the possible/available PV amperage.


Can I guess what you are doing with the "multimeter testing" on the other array?
You are setting the meter to amps, leaving everything connected to the charge controller, putting the red lead on PV+ and black lead on PV- ?

If so, that's the short circuit test, you are shorting PV+ to PV- through the meter.
I guess you've been getting lucky, having not caused any damage yet, sounds like Hedges hasn't been so lucky.
But don't do that while both PV+ and PV- are still connected to input of SCC (ask me how I know this.)
 
this post is leaving me a bit confused. I’m going to back up a bit and say what I know about these things in as basic terms as I know how and hope it’s helpful. Solar panels capture electricity you can’t take advantage of the electricity they capture unless you are using it. You can store the energy in batteries or use it in real time. If you have a battery bank and it is large enough to use the full capacity of your solar panels while charging you can simply discharge them until they are sufficiently depleted to pull the full output of your panels turn the solar charge controller back on and test away. Here is how I test my panels. I have 9 240 Watt solar panels 3s3p oriented essentially flat on the roof of my travel trailer. I have a 48v lifepo4 battery bank with 5120 watt hours of capacity. The max charge rate of my battery bank is 50 amps Or roughly 2600 watts so I have no issue pulling the full theoretical output of my panels. I just switch of the solar and let my batteries discharge until the are low enough to pull my panels full capacity for the length of time I intend to be testing. Once my solar charge controller has found the maximum power point. (Usually 2 or 3 minutes in the case of my charge controller.) use my dc clamp meter on the PV wire coming into my charge controller. I take that amperage reading and multiply it by the voltage that the solar panels are reading where the wires connect to the solar charge controller. That gives me the total watts my system is producing. Aside from arcing and the potential of getting shocked shorting the panels is useful in determining if the short circuit current is close to the rating of the panel ( a good indicator of the health of the panel) but it is pretty much useless in determining the wattage output of your array under your present sunlight conditions.
I don’t know what your experience level is with electricity. I don’t want to be offensive by assuming that because you don’t know how to test your panels that you don’t know how to handle electricity safely. I have done residential wiring on and off for nearly 35 years I understand how to handle voltages in the range of residential usage safely but until a few years ago I did not know how to test solar panels. If you are not completely certain of knowledge of electrical safety please educate yourself first. Diy solar always entails some risk. Best to take the risk of asking a question and being called stupid than to injure yourself or others. In the end asking a question will benefit yourself and help everyone else who has the same question but is to afraid to ask.
 
I know this because when I put my multimeter on the terminals it ALWAYS reads what the panels are producing, regardless of what the inverter is using.
... It's starting to sound like the shirt circuit is about it?

Do you mean you electrically connect terminals of ammeter to PV+ and PV- wires? That would be short-circuiting the PV string, because meter is (approximately) zero ohms.
I tried that once. With panels connected to my GT inverter (and therefore to a capacitor bank). It blew the fuse in my meter.

If you short out PV panel or string with ammeter, it will read short circuit current.
If you short out PV string to itself, short circuit current will flow. If you put clamp DC ammeter around it that will read short circuit current.

If you connect PV string through ammeter to SCC, it will read current drawn by loads and battery charging.
If you connect PV string to SCC and put clamp DC ammeter around it that will read current draw.

If you connect loads in excess of what wattage PV produces, ammeter will read Imp (or at least operating point SCC has selected)
If you discharge battery until it can accept 100% of what PV produces, ammeter will read Imp.


So if my panels are producing 45a, but my inverter is only requiring 10a to power the load, the clamp meter will read 10 amps because that's what's actively flowing through the wires. I also want to know the total being produced by they panels however.

Clamp ammeter on PV wire will show what panels are producing at that moment. Whether being used by inverter or charging batteries.
What it won't show is what panels could have produced given more load, but aren't producing at the moment because insufficient load.

You've got PV wires, battery wires, AC wires. You may not have access to separate wires for SCC output and inverter input; if separate components you would but not as part of an all-in-one. But you can calculate each of those, given PV voltage and battery voltage. (with some error due to inefficiency of SCC, which is probably 98% efficient.)
 
Watts are watts. SCC voltage conversion will consume some energy. So, watts sent to the battery + 5% is probably what the panels are producing. If, based on the size in watts of your PV installation, you believe your system is underperforming, start working back from there.

And if you want a more accurate number, look at the efficiency specification of your controller. If it claims 98% efficiency, only add 2%.
 
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