Solar charge controller weird voltage reading
Hello, I have 2 x solar panels installed. Each with 25V and 3,7 amps. The solar charge controller is called "CMT 30" and is supposed to be PWM. Now, if I read the voltage on the controller on ...
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https://www.aliexpress.com/item/32453845196.html
The instructions here (scroll down) say it is one of those that must have the battery connected first or the controller will be damaged.
It is PWM.
PWM does control the panel voltage by shorting it on and off once the batteries reach the set high voltage 14.4 or whatever. Until then, the panel voltage will be the same as battery voltage.
Not enough info why the batteries are not getting charged to 14,4 volts. If there is too much voltage drop on the wires between battery and controller, the controller will "see" 14.4 and stop voltage rising further, but the battery voltage will be lower than that set point.
Your array is quite small so if you have a bigger battery bank the array would not be enough to get the batts up before dark.
Your panels must in parallel, not in series, or the total voltage could fry the controller, and if it did still work, you are only getting half the amps you should be getting when they are in parallel.
Not enough info about your set-up and the camping scenario to know what's what.
I had a similar controller in one of my past set-ups and it did the job, even though it was an "eBay special". Can't just blame the controller for what it is and ignore other possible factors.
The instructions here (scroll down) say it is one of those that must have the battery connected first or the controller will be damaged.
It is PWM.
PWM does control the panel voltage by shorting it on and off once the batteries reach the set high voltage 14.4 or whatever. Until then, the panel voltage will be the same as battery voltage.
Not enough info why the batteries are not getting charged to 14,4 volts. If there is too much voltage drop on the wires between battery and controller, the controller will "see" 14.4 and stop voltage rising further, but the battery voltage will be lower than that set point.
Your array is quite small so if you have a bigger battery bank the array would not be enough to get the batts up before dark.
Your panels must in parallel, not in series, or the total voltage could fry the controller, and if it did still work, you are only getting half the amps you should be getting when they are in parallel.
Not enough info about your set-up and the camping scenario to know what's what.
I had a similar controller in one of my past set-ups and it did the job, even though it was an "eBay special". Can't just blame the controller for what it is and ignore other possible factors.
