Voltage issue or not?

Mickie

New Member
Joined
Feb 24, 2022
Messages
10
I'm new to solar and I'm wondering if this is an issue or it is how it's supposed to be.

I have a 12 setup. I discharged my battries and they are now down to 11.8v when I use a multimeter to check the voltage on the charge controller where the panel is connected I'm still seeing 11.8v so both battries and panel is showing 11.8v but when I disconnect the panel and check the voltage from the wires I'm getting 30+ volts. It's a 24v panel by the way.

My question is shouldn't the voltage from the panel side be higher than the battery voltage?
 

fratermus

Solar Addict
Joined
Mar 19, 2021
Messages
357
shouldn't the voltage from the panel side be higher than the battery voltage?

Depends.
  • On a PWM controller in Bulk stage panel voltage and battery voltage will be effectively identical (like you are seeing here). Note that a PWM controller with 24v panels and 12v batttery bank isn't going to perform so well. As in "making maybe a third of rated power at this state of charge".
  • On a MPPT controller Vpanel will typically be higher than Vbatt. Like 36v for your nominal 24v panels in Bulk. Likely even higher in late Absorption and Float.
You may want to make a list of the gear you have (make and model) and paste it into future posts. It will save us having to guess from afar what gear you have, and will increase your own familiarity with your setup. Win-win.
 

DThames

Photon Sorcerer
Joined
Nov 22, 2019
Messages
2,316
Your panels are a power source and their voltage is very sensitive to,
1. amount of sun
2. the electrical load on the panels

Your charger will load the panels and the voltage will drop. Fratermus described how different chargers work. This is very normal. The volts may or may not be higher than the battery. If you monitor the panel voltage as day breaks and the sun comes up, even on a MPPT charger, the voltage will be very close to the battery voltage until there is enough power for the MPPT to start doing its thing. So it really varies all over the place.
 
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