Solar array troubles

[Ietech]

I am having issues with one of my solar arrays. The array I’m having trouble with is a 15 panel array. The panels at 200 watt output. Each panel will put out 68 voc and 3.72 amps no load. I have these Hooked up in 5 series 3 parallel. It has been in service for three months now in this configuration. The problem I am having is it keeps blowing the negative fuse when I turn it on to the inverter. As long as I don’t turn on the disconnect to the inverter it is just fine. Voc is 315. Is this an inverter issue or panel issue. Any troubleshooting tips? Thanks in advance

 

[Rednecktek]

What's the make & model of your charge controller? Are you talking the negative fuse from the panels to the SCC or the fuse from the batteries to the inverter?

If it's the fuse between the panels and the inverter it sounds like you've got a bad connection in your combiner or the breaker has failed. Start by disconnecting 2 of the strings and see if it trips the breaker. Repeat for each string individually and hopefully 1 of the strings trips telling you which wires are flakey.

If it's the breaker between the battery and the inverter that's tripping then that should be independent of your panels and charge controller.

We're going to need a little more information like inverter make & model, maybe a diagram of how your system is wired together and we can help troubleshoot it.

 

[Jason.Blier]

Can you give more details?

What is the Max VOC of the solar inputs on the inverter/charge controller?
Is is blowing the "main" negative fuse on the PV input - or is it blowing a negative fuse on one of the panel strings?

 

[Ietech]

I have EG4 6500es inverters. The fuse that is blowing is a negative fuse in a combiner box. I have separated the three strings and have isolated the bad string. Now how do I determine which one or what is bad. My panels are manufactured in 2016. I have checked the inside of the panel wire junctions only to find the diodes are encased in silicone so not easy to check individually. Can I just check voltage from panel positive to panel case and negative to panel case to find the bad panel?

 

[Ietech]

 

[Ietech]

This is a label from my older array. All panels are the same as this just a little newer

 

[Jason.Blier]

A few things come to mind:

1. You have a wiring fault in the string. Shorting the positive and negative (if the negative conductor is grounded) could cause the fuse to blow.

2. You may also have a ground fault or current on one of your ground/bonding wires associated with that string. Improper grounding/bonding can cause a host of very weird and difficult issues to chase down.

3. If the fuse is too small (less than 2x the max amps of the panel), any shading on *that* string can cause the fuse to blow if you have 3 or more strings.

4. There is an internal wiring issue with one or more of the panels - could be a short in the J-Box somewhere. I’ve seen it happen in older panels with serviceable J-Boxes.

I hope that at least helps a bit and you find the issue.

Good luck and let us know how it goes.

-J

 

[Bud Martin]

Can we also see the pictures of your combiner box?

 

[Ietech]

I’m thinking I have a panel that shorted internally to ground. I’m not finding any wiring issues as of yet