Troubleshotting optimizers

[GRickard]

Hey guys, I ned some help. I'm scratching my head trying to figure out wat's going on here.

I have three strings with 16 SolarEdge P400 optimizers each. Two of them are working fine, but the third is not giving me any voltage. I tried breaking into the string and checking both parts getting nothing on either end. I am reading something like 263 ohms on the string. Not sure why I can't get one volt per panel.

Any ideas? Bad optimizer maybe? How would I know?

Thanks,
Greg

[Ampster]

Can you see any individual Optimizer data? Are there any error messages on your monitoring portal?

[GRickard]

Doesn't do any good to hook it to the inverter until I can read one volt per panel on the string. The inverter won't see it.

[Ampster]

Doesn't do any good to hook it to the inverter until I can read one volt per panel on the string. The inverter won't see it.

I was wondering if you had any data before this event? Perhaps this is a new installation in which case the usual installation troubleshooting techniques should be tried. Trial and error to eliminate the faulty Optimizer. Is there an expected value in Ohms that led to to try measuring that?

[GRickard]

I was wondering if you had any data before this event? Perhaps this is a new installation...

Yes it is a new install at my cousins house.

... in which case the usual installation troubleshooting techniques should be tried.

Any idea what that is? I've put in 10 SolarEdge systems and never had this problem.

Is there an expected value in Ohms that led to to try measuring that?

Not sure, I will be contacting SE support and maybe they can tell me.

[Ampster]

.........
Any idea what that is? I've put in 10 SolarEdge systems and never had this problem.
........

I would try an MC4 extension cable and eliminate the bad connection(s) or bad Optimizer(s). It is important to not disconnect the connectors under load.
Do you know the resistance that one Optimizer would read? If there was an open connection on a series string I would expect that it would read open and you would not measure any resistance.