Branch connector in parallel setup not doubling amps?

colemab

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This is the part that does not make any sense. If one of the branch connectors were bad, it should show up when one or the other panel is connected by it's self.
Yea it is blowing my mind! When I swapped out the branch connectors and got the same results, I decided to make this post.

I'm now starting to think my volt meter might be bad?
 

Texas-Mark

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I'm now starting to think my volt meter might be bad?

It does not sound like it, but you can also short the output of the branch connectors together and use the clamp meter on both of the panel cables going to the branch connectors. You should get the same 6 amps or so on each. If you do, then I would be suspecting the cables going to the combiner.
 

colemab

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Amazon delivered the new branch connectors after sundown last night. When I get back from lunch meeting, I plan to run your loop / shorted tests with the clamp meters and different branch connectors. In theory that should tell me which if any of the branch connectors are the issue. Then whatever ones run normal power (if any), I'll try the probe tests again. Fingers crossed I just have some bad branch connectors (for whatever odd reason).
 

colemab

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Ok so these tests were run later in the day then when I get full sun (down in this valley) but here are some results. Ignore the color of the wires as the trina panels have black wires coming out both positive an negative. The red one is read because it is cable to extend out to the branch connector.

These are with the renogy branch connectors looped back on themselves.
1.85 amps on the left, 2.29 on the right, 3.46 combined.
 

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colemab

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Next up the same test but with the linkpal branch connectors.

1.04 amps left, 1.54 amps right, 2.68 amps combined. Variance expected a bit because some moving clouds / not 100% clear day.
 

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colemab

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Open circuit test on left panel only with probes directly (no branch connector) 6.75 amps. These photos are being posted in the order taken. Which was as quickly as possible right after another.
 

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colemab

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Same open circuit test on right panel with probes directly (no branch connectors) 5.48 amps
 

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colemab

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Next up the loop / clamp test with bouge RV branch connectors. A cloud came and directly blocked the sun here.

.78 amps left, .81 amps right, 1.60 amps both
 

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colemab

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Finally, I un-looped the bouge branch connectors and did a probe test with both plugged in to the branch outputs (cloud moved a bit here).

6.43 amps combined.
 

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colemab

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If I get some time this weekend, I'll try to re-run these tests in full sun as the problem seems to occur with power trying to flow higher than ~6 or 7 amps with the original branch connectors but seemingly I couldn't achieve that today with the sun being out of ideal range.
 

Texas-Mark

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Ok, this may sound like a stupid question, but does your clamp meter actually measure amps with the probes? Usually there is a different place to plug the leads in for amps (vs voltage).

Otherwise your clamp reading seems right (adding up), other than being a bit low (assuming due to clouds).
 

colemab

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Well shit. Looking at the manual the probes on this one don't do amps. User error on the multi-meter I guess. I need to get another one that does and test that way to confirm though.

Thanks for your time man. Seriously, I would have never realized this.
 

Texas-Mark

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I need to get another one that does and test that way to confirm though.

Most will usually only go up to 10 amps, so don't try it in full sun with both panels or it may blow the meter fuse.
I think your clamp meter has confirmed things are working ok. But you can try what you did now again when the sun is cooperating more.
 

12VoltInstalls

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2 panels per string) down to a aims combiner box. I've checked each panel directly (as seen above in the photos) and after the branch connector individually and together. The readings after the branch connector are virtually the same for a single panel vs both panels. It matters not which ports are being used on the branch connector.
panels in 6 strings (2 panels per string) down to a aims combiner box. I've checked each panel directly (as seen above in the photos) and after the branch connector individually and together. The readings after the branch connector are virtually the same for a single panel vs both panels. It matters not which ports are being used on the branch connector.
I think you have something wonky for one.

Second, your descriptions sound like you missed the step of testing branch connectors at alternate legs.

Third I’m not sure you addressed the significance of this question:
You measure it to be 3.1A from each panel?
You have 6 series strings, right? Series doesn’t increase amps, just volts. Then you have 6 parallel connections. So the voltage maintains at string voltage and your amps should be times six of a pair.

If all six pairs are wired the same and all six are having wonky readings then something is magnificently wrong with the wiring or your description isn’t accurate to your setup.
 

Bud Martin

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OP should just use the Clamp-on DC Amp function of the meter to troubleshoot the problem by clamp on each one of the panel wire to see which one of the panel has current draw and which one does not without disturbing the connectors.
 

Texas-Mark

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OP should just use the Clamp-on DC Amp function of the meter to troubleshoot the problem by clamp on each one of the panel wire to see which one of the panel has current draw and which one does not without disturbing the connectors.

He has now done that now. The issue was he thought he could measure current directly with the meter leads on his meter, and was getting bogus readings since that meter does not support that.

There is nothing wrong with doing direct current readings if your meter can handle the current (and is capable).
 

Bud Martin

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My point about using clamp-on is to not to disturb the wiring at much as possible until you narrow down close to the suspected location, disconnecting/reconnecting the connectors that may have bad or intermittent connection may cause the issue to go away which makes it hard to find the root cause of the problems.
 
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