Nuno

I'm pretty positive its the panels fault. Today I'm getting slightly more power than the 2 previous days. Around 200W more (not a full sun day), so I'm guessing its due to the other 2 panels now being connected and outputting some power. Not sure at what rate are they working now, since the voltage of this string will be always lower than of the other two strings...

since I got down from 9 to 8 panels, I wonder if its worth to reconfigure my setup from: (3x300) + (3x300) + (3x300) to: (2x300) + (2x300) + (2x300) + (2x300) I need to get new cables for that and re-do some wiring... is it worth it?

thanks. will take a look I did open the panel's box but found out the whole thing was immersed(for lack of a better word) in some kind of silicone. I guess thats to avoid people messing up with it 😕 They dont really have a brand.. some sort of generic

Update! With only the bad string connected, I took out one of the panels and I think I got lucky right on the first one! I tried to connect the string with 2 panels to the inverter and it began charging! So i guess I found out the culprit. Is it worth to open the panel's "box" and look into some possible issues I can fix? Or is it good to replace? (its only 2 years old )

Hi folks, Yesterday I noticed my production was 30% down from the usual. I have 3 strings of panels (3x330w each). Each string has the 3 panels in series, to get to around 110V, and then they all connect in parallel to my Axpert Inverter. After some quick diagnostics, I found out one of the strings was not giving any power to the inverter. (I realized this by disconnecting one by one, and noticing that this one did not make any difference being unplugged or not). I spent most of my day trying to check the cables (some of them underground), and making sure there was no connectivity issue. I tested connectivity with my multimeter and everything seemed to be ok (I did not want to dig the underground cables...) I checked the voltage of this particular string, and it was ok at around 110V. Today I tried something else, and this is when things begin to get weird. I disconnected completely the 2 good strings. I measured the voltage of the bad string before connecting to fuse box+inverter. 110V as expected. Once I plug things on, the voltage drops to about 50-60V, and the inverter is not able to "connect" the charge (it does this "click" sounds every couple of seconds). I'm lost trying to understand what this might be. Please let me know if you have any ideas. I really do miss those precious 30% now in winter time

yes, thats the one

check my post with the drawing, I connected neutral directly to ground in the bus bar

Ok guys, mystery solved! Kind of .... I was experimenting connecting just one battery at a time to check if maybe one of them was fault. Then I noticed something odd. Sometimes when I turned on the battery switch it went to 7V, other times it stayed off. I then tried the same thing with the 3 of them together and got the same result... no consistent behavior. Then it ocurred to me that maybe the fact that I'm switching them on one by one is somehow confusing the inverter<->battery, and by safety it shuts down. So I unplugged the inverter cables, turn them all on (getting 50.4V), and then plugged in the cables (getting the expected spark in the last connected terminal). The charge held up at 50.4. So I switched on the panels and finally the inverter came alive My bad for not having a proper DC breaker, this whole thing might have been avoided! Phew! thanks everyone

the three of them read 50.4V when disconnected from the inverter

here it goes. the first one is the right connection, the second one is highlighting the mistake. Again, the battery switch was OFF at the time, but the cables were connected to the inverter, thus closing the circuit.

Thanks @Coulomb You are right about the conductivity. I held it longer than 10seconds and after a while the beep went off. Measuring the ohms, i got 3.3 MΩ, at the battery in and 0.3 MΩ, at AC out (no battery connected) About the batteries, these are lithium, so they have 2 + terminals, 2 - terminals, a small lcd and a switch to turn it on. When the battery is off, there is no voltage across the terminals (which was the case when I misconnected the cables by plugging both in the negative terminals) BUT, there is continuity between the 2 + terminals, or between the 2 - terminals. So I did close the circuit of the battery cables, even though the battery was off. If this is not clear maybe I can take a picture of it

sorry, not sure the right term in english... I mean there is conductivity between the two ends

Its not a Pylon, but very similar! I tried connecting just one and turning the battery switch on, it went back to 6..7V and no sign of life in the inverter

Hi guys I may have not explained myself properly. I think the short was without battery interference... so probably a capacitor? the confusion was due to the terminals in the lithium batteries, I had connected the negatives, and then the positive cable got connected to ANOTHER negative terminal as well. With the batteries disconected I get 50.1 in each. Once I get them plugged in to the inveter, it imediately drops to 6..7V like I said above. I'm actually afraid to try it again in case I fry it even more 😛 You mean there is nothing strange in the multimeter reading continuity between the + and - terminals of battery In and also between + and - of AC out?? (also, how do I reset the inverter?the manual doesnt mention anything...)

I was switching from lead-acid to new lithium batteries, prepared everything well in advance and rehearsed all the connections I had to undo and do. This morning, for some stupid reason, I had an epic failure for a few seconds, I pretty sure I short circuited the inverter battery IN terminals. It actually happened to me a couple of years back, at that time something blew up and smoke came out. This time, no noise, no smell.... but the inverter is pretty much dead. When I connected the batteries and tested voltage it read 7V and went up 0.1 every 5 seconds or so... stabilizing at round 30. Turning on the solar panels made no difference. I disconnected everything and with the multimeter I testes for continuity between the negative and positive terminals of Battery IN, and it beeped (which means there is a circuit). Same thing for - and + of AC out. So, am I right that this is messed up and needs repair? (Axpert Inverter)