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miami337 avatar image
miami337 asked

Voltage Drop at MPPT 100/50

When I connect my PV (-) and (+) to my MPPT 100/50, my voltage immediately drops from 41V to 29V. This of course keeps the voltage too low for my 28V system to charge, so the charger stays "off".

I've replaced all MC4 connections between the panels and the MPPT just to be safe, yet the exact same voltage drop happens right when I connect to wires to the MPPT controller.

Firmware is updated.

Any thoughts on a potential solution?

MPPT SmartSolar
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Alexandra avatar image
Alexandra answered ·

@miami337

It is normal for panel voltage to drop from VOC under load.

You basically need at least one more panel to work a higher string voltage thus taking advantage of the mppt.

The one panel setup works better with a pwm controller.

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miami337 avatar image miami337 commented ·
Thanks @Alexandra - I actually have two panels in series to get the voltage up to the 41v, I didn't realize the voltage drop would be so significant. I'll be adding two more panels shortly to the circuit so my voltage should be around 80 at that point. Sounds like that may solve my issue. Thanks!
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