Hi
My victron MPPT smartsolar 75/15 is not charging anymore.
I checked everything on the roof of my van (3x100W panels in series) and everything is okay, and the voltage measured is 55V, so everything’s fine.
It charged fine since 2 years but today, no more.
The strange thing is,
when the 2 wires from my solar panel are plugged into the MPPT I measure 13V (I should have 55V) whereas when I unplugged them (or only the +) I get 55V !!
So I think my MPPT is dead??
Thanks for your help
Can you measure the current of the PV (if it is low there is something with your PV)
Very common for a bad connection between the mppt and array to form a high resistance and not allow much current to flow. This shows up as the array voltage falling to the battery voltage.
Check connections between the mppt and array. Fuses/breakers and mc4 connectors. Lastly bypass one panel at a time.
@fredvduin @water_rat thanks guys for your help. I’ve just checked the victron app and it says it hasn’t charged yesterday either.
But good news it’s currently charging again without me touching anything…
Maybe I have a loose MC4 connection inducing this behaviour? But I don’t think so since I’ve measured continuity beween all wires, and checked the voltage for the 3 panels and everything seemed ok (55-60v fluctuating, meaning the panels are fine and cables too, when they are not linked to the MPPT). Maybe an MC4 can lose contact only when under load (aka plugged in the MPPT)? strange if so…
I know but my MC4 are compatible since they worked fine since 2 years in this installation. I had to repair 2 of them though but they worked fine after the repair.
Ok it was charging fine during 2 hours or so, and now nothing again. This behaviour is very weird. I don’t know if the MPPT is faulty or one of the MC4.
If it was an MC4 I shouldn’t get any voltage at the panels input/output, but I get the regular voltage (55 - 60v). I don’t know why this voltage is not used by the MPPT when I plugged the panels wires to it.
Go do a full inspection. Check all the connectors and connections. Not a cursory visual check, be thorough.
It is not uncommon for time and the elements to cause wear, corrosion etc.
The many cycles will eventually convert an imperfect connection into a failure.
It’s why we inspect annually, to try catch problems before they happen.
Thanks @nickdb for your help. Yes I have to do some work I guess. What is strange is, it worked fine during 2h continuously today, charging almost at max intensity without any problem. Then now it doesn’t work anymore. A faulty MC4 wouldnt have allowed 2h charging like this, no? And I wouldn’t have the usual 55V at my panels output if an MC4 was faulty, as well. I don’t know…
Chargers tend to work or not. 99% of these problems usually end up as something iffy on the PV side. Most members here will attest to that.
I totally trust you on this, Victron is not the kind of device to fail like this. I will investigate the MC4s, maybe replace them since there is no effective way to check if they are working or not.
