Instructions for setting up the MPPT-V08A Lithium Solar Charge Controller with CN3722
The information in the listings for these modules is virtually incomprehensible so after a bit of trial and error I’ve worked out how to set the maximum output current for your solar panel and the cut off voltage for your batteries. The instructions below are using the following items.
12 V 10 W Solar Panel from AliExpress
MPPT Solar Charge Controller from eBay or AliExpress
Two 18650 batteries and holder
Step 1
First turn the voltage pot fully anti-clockwise and turn the MPPT pot fully clockwise. You will be able to hear them click when they are fully turned.
Step 2
Connect the solar panel but don’t connect the batteries.
Connect a voltmeter across the battery terminals.
Turn the MPPT pot anticlockwise until a voltage reading appears and the LED flashes blue
Step 3
Connect batteries that aren’t fully charged via an ammeter.
Turn the voltage pot clockwise until a reading appears and the LED turns red.
Step 4
Adjust the MPPT pot to reach the highest value on the ammeter. This is the maximum charging current your solar panel can provide.
Step 5
Charge the batteries in a quality charger until they are full.
Connect the charged batteries.
Slowly turn the voltage pot anti-clockwise until the current shown on the ammeter is 0. This is the cut off for charging when the batteries are full IE the maximum charging voltage.
Advice
Note that the above is just a tutorial for setting up these devices. Your finished system must include battery balancing so your batteries are evenly charged. Without a balancing system your maximum charging voltage could be unevenly distributed. For example if your maximum is set at 16.8 for 4 batteries you might expect them all to be topped up to 4.2v but without the BMS they are could have any value that adds up to 16.8v. Some of them could be overcharging.