My 150/70 is having a strange DC at its input during some nights, not all. Here's an example:
Almost 18V at input. Suddenly around 23.56 it has gone to zero but it came again as you can see.
This MPPT is a part of a bluetooth parallel network, with 2 more 250/60 in which none of them shows this behavior.
What could be this about? It is connected to 3 strings, it's chassis is grounded, as well as the panels frames.
Running fw version 1.54.
hi, have you some street lights around of your panels or near a busy street that could explain some parasites effects?!?
You have almost no amps. It may just be some small fluctuations in volts, but no current. Some of the cheaper DAQ systems tell you to put a high resistance resistor across it to stop reading the noise.
so 2 things, can you live with it or put a load resistance?
Hello,
I did not see this again, so I could'nt test further. I don't think is outside noise, it seems internally generated, but I can't be sure at the moment. A high value resistor on PV side seems an interesting idea to me, maybe it can pull the line down and override this noise, wherever it is coming from.
haha.. after to have saw the « interstellar » movie, each time i see something strange things, i try to find if there are any kind of ghosts hidden codes!! ..for to kill the street light static effect on my first 18v panel (was around 15-17v static because a street light is near and switch off by overheat randomly doing strange Morse code look like), i has put 1 kilo-ohms (1 watt) in parallel.. since, the night voltage still below 2 volts.. if you short your panel with a ampere meter (during the night), the value (in my case 10 to 12ma) tell how much current you need to kill (1k = 18ma was enough to me)..
That's not a negative amperage, is it? I thought it was zero per the graph, but could be a bad diode on the panel, discharging the battery and heating the panel?
also check if it is a full moon on a clear night
ooh yes, a full moon can also do that and with some clouds, have stranges on/off PV output!! ..super idea fantail!!
I have similar from Moonlight but looks to consistant for that. Street-lighting....?
