Feed on

Today we’ll be taking a quick look at the Solar Charge Controller CMTP02 which is rated for 10A and used to recharge your 12V or 24V battery and power your load; they say that your solar panels / batteries should be matched, this was given to me and I believe it’s damaged.

IMG_4102 IMG_4103

A few seconds later and we’re in.


We’ve got all analog components, a fuse and 3 transistors or mosfets with no part number labeling and the back plate acts as a heatsink for them. The first 2 are connected together and configured to recharge the battery and the last one is used to switch the load. This solar charger (might) use PWM to charge the battery which means the solar panels voltage would directly be applied to the battery for a certain amount of time, it would probably be more efficient than using a DC-DC or transistor to step it down but not the best if something does go wrong. PCB date code is July 2009 to March 2014.


There’s a Ti CD40106B Hex Schmitt Trigger which is likely being used as an oscillator for the PWM and Ti LM324 op-amp with lots of resistors around it which would be used to control the transistors/mosfets and LEDs. Apart from that there isn’t much else.

5 Responses to “Inside the Solar Charge Controller CMTP02 (Dated 2014)”

  1. Rainer Ernst says:

    Hi there.
    Thanks for you post. I sadly bought this controller. He is completely crap (at least mine). I didn’t realise any PWM from it. It disconnects panel at 14,8V battery voltage (TOO HIGH) and connects back if the voltage drops under 14,2V. So there is no real PWM.
    Do you know for what is that potentiometer at the top in the middle? I tried to adjust the disconnecting voltage but it didn’t work with that.


  2. JakDac says:

    What part do you repair ?

  3. Emmanuel says:

    Hi Everyone,

    Please who can tell me the maximum input voltage supported by this CMPT02 charge controller? Can it work with my 36V, 300W solar panel?

  4. Josh says:

    I’ve got two of these.. I’m feeding it with a dell power supply ~19,8 volts and 5 amps, working just fine for 2 sealed lead acid batteries as a simple wall charger, 20 Ahrs

Leave a Reply