Two panels in parallel, but amps don’t increase

[AlumniCU]

I have two 100 W panels (both Renogy Eclipse) wired in parallel. This morning, each alone produces about 2.6 amps, but when wired together the amps don’t change... All positive outs from the panels connect to positive on controller, all negatives connect to the negative on controller. Thoughts?


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[DaveInDenver]

Do you have blocking diodes?

 

[dwh]

Where in the three circuits are you measuring current ?

Probably from the charge controller's readout.

I think there's a loose wire.

 

[AlumniCU]

Where in the three circuits are you measuring current ?

I’m reading from the charge controller.


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[AlumniCU]

Do you have blocking diodes?

I do not.


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[AlumniCU]

Okay - took apart and reconnected everything - amps doubled.

Thanks for responding.

In any case, should I add diodes?


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[DaveInDenver]

In any case, should I add diodes?

Apparently they are either already in the panels since you don't need them after you've fixed the loose connection.

 

[dwh]

The panels have bypass diodes. The charge controller has a blocking diode to prevent backfeed from the battery to the solar.

It's all good.

 

[DaveInDenver]

So what happens if one module goes shaded ?

You'll find out if the panels have blocking diodes built-in or not I suspect.

 

[john61ct]

Also note a nearly full bank will not accept much power input.

Do your testing with the bank at 60% or less, or get big enough loads cranking.

 

[AlumniCU]

Also note a nearly full bank will not accept much power input.

Do your testing with the bank at 60% or less, or get big enough loads cranking.

This may have been the issue - reset on a different battery, then put on a load. Eventually it blew the 10A inline fuse.

Should in replace the fuse with a 15A, or stay with 10? With 200W, and hitting 10A, thinking I need to increase the fuse amperage. Will this have consequences?

I’m new at this - grateful to learn from you all.


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[AlumniCU]

Should in replace the fuse with a 15A, or stay with 10? With 200W, and hitting 10A, thinking I need to increase the fuse amperage. Will this have consequences?

Assuming your conductor size and charge controller is adequate, 15A fuse is good idea. Even then, 200W 12V nominal system has potential to load right at or slightly over 15A. I mention ”potential to”, Thats assuming perfect sunlight, ambient temperature, etc. Probably not going to occur daily, but definitely can under right conditions.

As aside,
Alot of small solar installs dont use any fuses on the solar side of the controller.
The solar array is current limited. For example, your system 200W. Given adequate conductor size, the array cant produce enough energy to harm the wiring.

Thanks. The 10A fuse that blew is between controller and battery, near battery. Controller is up to 30A. Wiring is 10/12 gauge.




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[luthj]

I would choose a fuse that will protect the wire. For 10 gauge I would go with a 20A. The higher rated fuse is safe for the wire, and will have a lower voltage drop. No need to fuse the panels, unless the max fault current (panels output in this case) is greater than the wires rated current.

 

[Ducky's Dad]

Go Power told me to fuse the positive from the panel to the controller at 10amps and the positive from the controller to the battery at 30amps. Single 100W panel with 10AWG to a 30amp controller.