The controller is housed inside a case with a 200ah lithium battery.
It is connected to a 180w solar power on the roof of the car.
Been working just fine up to a week ago.
Today i opened everything up and checked the fuses all fine.
It worked fine for most of the day, then nothing again.
Solar panel is still giving 20+v.
Faulty unit?
The PV only reads 13.11V and is lower than the required to work. (vbat +5 to start) Where did you measure the voltage of the panel? Could even be a dirty panel that caused the voltage drop. Also replace the fuse to be 100%.
There is 20+volts at both ends of the cable coming from the panel. Am confident it’s not that nor the Anderson plugs in use.
So, there is enough voltage but the controller doesn’t seem to register it.
I will change the fuse though just to make sure.
Definitely sounds like a poor connection somewhere between the panels and the controller, this is the usual reason for this. Using a multimeter to measure voltage on the ends of the leads does not draw any power so it still reads full voltage through a poor connection, but the mppt draws power and the voltage drops over the poor connection. You need to check voltages at all connections when the system is connected. MC4 connectors can often do this.
@markeroonie I should also have said the poor connection could be within a panel.
Another test you can do as you only have a low voltage low current system is to measure the short circuit current with the multimeter set to a 10A range. If everything is fine you should read 7-10A for your panel depending on light, this is a better test than open circuit voltage. Only measure for a few seconds as this can heat up your multimeter. If you measure no current then you have a poor connection. Search youtube for solar panel short circuit current test if you need info on this.
My multimeter only does ac amp load, not dc
Then try with a 24v 50w lightbulb as load to the pv-in, at 20v it should pull some amps.
Did that, works just fine, so power is ok from the solar panel.
Will re-check the fuse next
Solution found.
To my surprise and embarrassment, it was a lead on one of the Anderson plugs, not locking in properly, so when i pushed one plug onto the other, one of the leads moved back just enough to no longer make contact. Lucky no shorting happened.
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