Totally new at this. Trailer worked fine until the other day at 105•f, but now when I flip the combiner switches for the 2 strings of PVs, I get 0 power from PV per the classic, which keeps it in resting mode. I can read 168 volts (with a multi meter) coming in from PV at combiner switch until I flip the combiner switches to the classic 250. Other info. 48v system, dual sunny island converters. Standard DC solar trailer. I have checked all setting, but from everything I’m seeing I feel like internal short. Lost, thinking damaged classic. Thanks for any help, sorry if I didn’t get it in the right topic. I have been searching for this issue and keep coming up with nothing.
If you have a multi meter and know how to safely use it - turn off the combiner box breakers and test the PV voltage on hot side of those combiner breakers. Then turn them back on and test voltage on output side of the breakers. Are there any other breakers between the combiner box and the Classic ? There should be one that protects that wire . Find that breaker and test voltages there. Finally if all is well open up the Classic and test at the terminals where the PV wires connect up.
Your photo of MNGP display shows 0 volts so no PV voltage to Classic. Something must not be connected somewhere along the way - the PV input breaker off ?
Larry
I have power at the breaker between panels and classic, with the breaker off. PV is putting out around 160vlts. Then I flip breaker on that’s feeds the classic and it drops to 0 volts. I so I I can think is grounded after breaker. But that’s feed directly to classic. Everything thing else on the system is working other than low batteries and SOC at 15%. Have a second setup identical and dble checked all settings. Everything thing matched up.
Hi Chad..,
SO, with Combiner breakers opened (switched to OFF), The Classic reads Vin, as 0.0 Volts?
Think that this is what you are saying.
As Larry mentioned you should double-check at the PV input terminals of the Classic with the PV breakers and any input breaker to the Classic=OFF.
If you use your DMM to measure between these PV in terminals, and the reading IS 0 volts, then almost always, that means that the power FETs in the Classic have been blown up, and, shorted to ground (negative).
YES, your batteries are very low, and should be immediately recharged, if this system is still using the Flooded LA batteries. Do NOT let the batteries remain in this low SOC for any additional time -- you know this, am sure.
FWIW, Good Luck, Vic
Yes, with breakers off I have power coming in from panels (PV) to breaker on DMM. When breaker is switched on(closed) volts goes to 0 on DMM. I feel like the FETs are damaged then. Everything got extremely hot the other day inside the cabinet.
Really, the best test is to look at the input voltage to the Classic with the PV input breaker open, just to make sure.
If the PV input terminals of the Classic get shorted together (or the PV + terminal is shorted to ground elsewhere), when the Classic is powered up from the battery, even for a moment, this usually will destroy the power FETs. Am not suggesting that what happened to your system.
Hope that you have Grid power, or a genset to power the chargers in the Si inverters (or other charge sources) to get your batteries recharged soon (assuming that they are still FLAs).
Good Luck, Vic
Thank you for the Info!!!
I’m a great aircraft tech, but this is all new to me. I think I could diagnose a GE90 Engine issue on a 777 easier. Lol
Also do not have backup charging for the batteries. If I was the swap out the classic from the other trailer will I have data issues between it and my inverters? Same identical set up, but I didn’t know if it would see the different classic or classic realize it’s connected to different inverters.
Hi Chad..,
I do NOT know anything about the operation of the Classics when teamed with Si inverters.
But it should be worth a try, IMO.
Just be very, very careful when dealing with the PV wiring. The PV string voltage is relatively high, as you know. These DC voltages can be lethal. Make absolutely certain that the PV breakers feeding the Classics are open, and the battery breakers are also open. Check with your DMM, carefully.
There may be a way to easily shade the PVs.
FNG, Ryan knows a lot about these DC Power trailers, and probably other members, as well.
AND, just saw this, FYI:
http://midniteftp.com/forum/index.php?topic=5192.0
Be careful, Good Luck, Vic
Why not just charge the batteries from the other trailer ? Not sure how close your trailers are but you could probably just run some wires over from the other trailer to the batteries. It would be a lot easier than swapping out the Classic.
Larry