Problem with CMP12/24 Solar Charger Controller (HELP PLEASE!)

[Solar88]

Hi. Someone had told me the parameters of my solar panel and 12V 44Ah battery were compatible with the CMP12/24 charger controller.

The params of my solar panel: 24V 3.6A

I recently bought this charger controller. So, I connected the battery first then the solar panel and finally customer to the charger controller. It actually has worked fine for about 1 month. After this time the charger controller went wrong. I could measure 15,6V on the battery!

Plus, I do not really see why its output keeps changing from Low level to High level??:-?

According to the tests all the 3x3205 N channel MOSFETs seems to be good. :-(

Could you please help me with this problem?

Cheers, Solar88

 

[chuckey]

If the battery is discharged (too much load on it) and wants to be charged up at 10A, the controller will go into overcurrent mode, i.e. reduce its output voltage to the point where the current is 3.6A. It could be that the battery is just plain faulty. So first of all, disconnect any load from the battery, if the voltage starts to rise, you have fixed the fault (too much load). Then disconnect the battery, does the controller's output voltage reach 26V or there abouts?, if it does then the battery is faulty.
If both the previous tests fail, you could try to reset the output voltage, (its unlikely to work!!). Down at the bottom of the PCB there is a little blue multiturn pot. This almost certainly adjusts the output voltage via the "screw "head on it. So put a tiny blob of paint/ink/scratch on the screw so you can identify its present position, relative to its case. Make a sketch of this, because you might have to go back to this position again. Twiddle the screw and monitor the controller voltage, if you can get it back to 27.6 V, this is about right for a 24V lead acid battery.
Frank

 

[Solar88]

Thanks Frank for your quick reply.

Well, i tested it again
The steps i followed:

1. The akkumulator had 12,2V with no load on it
2. Then I connected my laptop to it and after 4 minutes its voltage fell down to 11,8V
3. Its output got started to change between High and Low levels
4. I disconnected my laptop from the output of the charger controller
5. I could measure the full battery voltage again (12,2V)

However its handbook reads it should turn off its output at 10,8V instead of 11,8V.
I twiddled 3 times right then 6 times left the screw and monitored the output voltage of the charger controller. I realized nothing has changed on its output. Then twiddled the screw to the basic position.

What could i do wrong?
Looking forward to seeing your reply.

Solar88