I have two 39 watt deck mounted sunbeam system panels that have worked perfectly for 3 seasons , these are wired in parallel to a victron 75/15 MPPT. Last week I noticed the output was a lot less then usual and ran some tests.
It looks like I have an issue with the port side 39 watt panel but I am not sure what it is. When I disconnect the port panel from the starboard and run on a multi-meter the results on the port panel are about what I would expect (although possibly the volts are a little low). With the port panel disconnected today the starboard panel was producing exactly what I would expect in full sun on the victron mppt. Here’s where it gets a bit confusing….when I reconnected the port panel to the starboard in parallel it dropped the whole system down to next to nothing, I am at a loss as to how that can happen in a parallel setup? I would have thought in parallel if the panel was faulty it would simply add nothing rather than impact the other panel’s performance, It’s behaving like it is in series not parallel?
So in summary, when the starboard panel is connected to the mppt it is producing as expected , when I test the port panel on the multi meter it is producing as expected but when I connect together the amps drop to nothing.
Any ideas would be greatly appreciate.
