great, thank you I will try it out… :+1:
Regarding XL4015, is there any indicator to see whether the battery is fully charged?
supersonic, in the above picture two leds can be seen at the lower right board corner; out of these two the one at the left (closest to the LM358) is on when in CC mode, while the rightmost one lights up (and the left one turns off) once the output current has tapered off below 10% of the set ratio at the right (CC) trimpot.
Alternative unit with slightly different PCB and colored leds:
These boards won't work in constant current mode with less than ≈7V of input, bear this in mind though. 
Cheers ^:)
Originally posted on Thu, 05/17/2018 - 01:23; edited to add extra clarification info.
Wait, is that why when I tried to charge super capacitors with a 5V power supply, the current kept going up until the power supply shut off, and not doing it with a laptop power supply?
Now I get it. I have 5 of them regular buck converters, and 5 of them which have MPPT operation.
These work very well at parallel charging, and safe low voltage recovery voltage at <2V lithium ion cells at 50-100mA.
I don’t think you should do that. I’ve seen elsewhere that these modules need isolation if powered from the same supply.
Anyways has anyone tried them TP5100 heard they can charge both single and 2S
Well, others like pilotdog68 have done it successfully besides me:
The above is a custom powerbank I made for a close friend. It has a good old PCB featuring a single TP4056 charging chip onboard which can be seen just under the red cable in the photo, besides the onboard 5mm led. As can be seen in the photo I boosted its charging capability with an additional TP4056 board, and that thing is still operating. The powerbank is now housed inside a different transparency box because he once crashed it hard. :-D
Cheers :-)
Are you sure these modules will work fine without any issues if you wire them to a common power supply without any isolation? If so then I would like to do that setup with 2 TP5000 modules (the other type, the red one which HKJ reviewed) in parallel to charge 2 LiFePO4 cells simultaneously.