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jjan avatar image
jjan asked

Mppt150/45 stops charging after panels are shaded (even for a second)

My system consists of 6 - 365 watt panels arranged in 3 parallel legs of 2 panels in series. The max voltage of the paired panels is 90 volts. These panels are mounted on the roof of my motorhome. Regardless of the state of charge of the 48v lithium battery bank, and regardless of the actual power being generated at the time, 3 out of 4 times that I travel under an overpass, the MPPT stops providing power (usually shows 1 to 10 watts). The only way to restart power generation is to disconnect the panels and battery from the MPPT for a few minutes, and reconnecting everything. So in simple terms, 1 second before the overpass the MPPT could be generating 1000watts, and near "0" one second after. A full MPPT reset is the only way to restart power generation. All connections have been checked and rechecked. Any suggestions?

mppt charging
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Alexandra avatar image
Alexandra answered ·

@JJAN

Does Victron Connect not give an error or a reason?

Usually for troubleshooting a firmware update is recommended first. You have checked the install and it clearly works before the shading.

Maybe rebulk offset? What are the settings?

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jjan avatar image
jjan answered ·

I can confirm that the MPPT is on the latest firmware. I can also confirm that the unit was clearly working beforehand. As mentioned in my original post, the unit will go from 1000watts, to virtually "0" (1 to 10 watts) immediately after a momentary shading event. The are no error codes. The bulk offset is 0.4v. For clarity, this "shading shutdown" occurs at all battery voltages.


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Alexandra avatar image Alexandra ♦ commented ·
@JJAN

Weird behaviour. Probably best to take it back and get it checked out.

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pwfarnell avatar image
pwfarnell answered ·

Is it going to float based on tail current setting, the panel shades current drops, but with lithiums the voltage does not drop. I know this is a long shot as I thought the tail current option to end absorption does not apply on lithium setting.


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seb71 avatar image seb71 commented ·
Interesting theory. But the current should be under the Tail Current value for 1 minute.

And also this appears to be a recent thing.

So it's more likely a defective unit.

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