My system is a 24v one. I think the mppt 150/60 is backfeeding the panels when it's dark. Voltage at the mppt panel input terminals when dark is 26.9v. Even when the panel wires are disconnected there's still the same voltage at the mppt panel input terminals.
The mppt indicates it's in Bulk mode.
Does this indicate a faulty mppt?
If there is no PV connected at all there should be no voltage on the pv terminals. I just checked two of mine.
If pv is connected at night there will be battery voltage maybe plus 0.1 or 0.2v with the meter.
What does the app say about the charger state or condition? Does it still work otherwise?
In theory the diodes in the panels will prevent power dissipation out that way?
Modern panels are typically fittted with bypass diodes, which is different to blocking diodes. Blocking diodes you typically find fitted inline at the time of an install, although I have not seen many installations with them since charge controllers in general usually offer protection against reverse currents.
I will check it again tonight.
Not sure if this is related but my system also has a BMV 712 which usually shows a draw of about .32 amps or about 9 watts when it's dark. I assume this is the power required to run the 2 bms in the 2 Battle Born batteries.
The bmv measures what is coming out of the battery through the shunt .
9w sounds about right for an mppt on standby and a bmv.
If that is all that is being drawn out of the battery, then I dont think you are feeding power back out the panels, the drain does not suggest that at all.
There is voltage at the panel terminals of the mppt which is fed to the panels and the same voltage at the panels. So, there must be some problem.
Though not mentioned there is a current draw of about .17ma at the combiner box output from the panels.
I'll find out more tonight.....
It's dark and I checked the mppt. There is about 27.01v at the PV terminals of the mppt.
The Battery State is Off
'Don't know what the "Vitural Load Output----State---On is about or if it's set incorrectly.
Here's a screenshot of the mppt VictronConnect figures
Detecting battery voltage on disconnected PV terminals typically indicates a fault with the MPPT, please get in touch with your Victron dealer to discuss a solution.
Sounds like your diodes in the MMPT have been damaged, this can be caused by powering up the MMPT with a reversed polarity on one of the strings
(I have seen this before)!!
No warranty from a bad install
Reverse polarity shouldn't actually do that. The datasheet claims protection against it. To me that means warranty still valid, even if that caused the failure.
How can it be warranted when the customer caused the damage to the MMTP ?
