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seltsam avatar image
seltsam asked

Low voltage readings on MPPT 75/15

I was wondering why my battery was empty and checked the setup again. Turns out that the charger doesn't seem to show and handle the wattage that is actally put out by the panels:


Charger display: 16v 1.8A

Multimeter readings: 30v 3.4A (measured on the disconnected panel cables)


How is this possible? (The battery is not full, and also pluging in a laptop or something doesn't increase the reading.)


Could this have to do with a firmware update lately? If yes, how can I roll back the firmware?


Thank you

MPPT Controllers
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seltsam avatar image seltsam commented ·

Here you find pictures from my meassurements vs the reading in the app. Should I refund the Charger?


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Robert avatar image
Robert answered ·

Hello,

what size panels? how many? parallel? series? Do you have a screenshot of the 16V 1.8A reading? How are you getting 3.4A on disconnected panel cables? What battery setup are you using? Plugging in a laptop (where?) doesn't increase what reading?

Robert

MI

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seltsam avatar image seltsam commented ·

Hi Robert,

please keep in Mind that the Panel-Setup worked as expected previously.

Panel Size shouldn't be an issue, since I didn't change anything on my setup.


> What size panels?
100W

> how many?

2

> parallel? / series?

Readings are off for both, tried it.

> Do you have a screenshot of the 16V 1.8A reading?

No.

> How are you getting 3.4A on disconnected panel cables?

1. Remove the panel-cables from the PV-connections on the charger

2. Put your volt-meter to the cables, plus and minux

3. Read what the volt-meter shows

> What battery setup are you using?

90Ah lead

> Plugging in a laptop (where?) doesn't increase what reading?

Connect my laptop-charger to the controller output to have a source that pulls power (to make sure its not the batteries fault).


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