eBay adjustable CC/CV module for 4.3v cell charging?

Yeah, set open circuit voltage to 4.32-4.33v. You have to remove power occasionally after it hits the set point and see where the cells are, though. I think one of the modules with built-in volt/amp meters might be better than the 3-pot boards, I'd rather monitor it myself than depend on something so cheap to shut off without blowing something up.

Here's another version of the 3-pot board, this one capable of 5A: http://www.ebay.com/itm/370884975034

You know, I don't think the third pot does anything but adjust the point where the charge indicator LED changes color, I don't think it shuts off. Depending on the set voltage that may not be anything to worry about.

nice setup

What did you use to attach the heatsink? just thermal grease since the screws are holding it?

Nah, there's 2 small screws through the AL into the plastic frame of the box, the lower screw through the regulator also passes through into the plastic, the upper screw is threaded into the aluminum plate. I've charged 4 flat cells at 4A and it didn't get even detectably warm, it doesn't need a heatsink but it was what jumped out of the junk box into my hand, so I used it. :party:

I have the same board. But the directions are still confusing to me. I wish someone would make a video on how to charge li-ions or maybe even LiFePO4s

Oh hehe, I saw metal and immediately thought heatsink.

Worrisome that the first unit failed as it looks like half of the unit I’m toying around with. :frowning:

!!

I managed to resurrect mine - turns out, the through holes are not vias, the pads on top and bottom are not connected! I had the wires soldered over the top of the holes, all but the out+ had solder filling the holes and making the connection to the bottom layer. Resoldered everything and it works again.

OK, I think I have it figured out. The middle pot does nothing but set the point (based on current) when the 'charge' LED turns off and lights the 'OK' LED. The board does not shut off when finished, but when the cell voltage is equal to the regulator output voltage, no current will flow.

Set the open circuit voltage to 4.20v, 4.30v, 4.35v, whatever.

Short the outputs with an ammeter, adjust the current pot to the desired 'end current', or the amperage where you want the LEDs to indicate charge complete - say .1A. Then adjust the middle pot until the middle 'CH' LED just turns off. During the charge when current to the cell falls below that point the LEDs will change.

Short outputs again with the ammeter, set the max charge current, say 1A.

At the start of a charge cycle with a flat cell, current will be limited to 1A (the cell would take more than that, if it weren't limited). The far right LED (marked 'CC/CV') will be on, and the middle 'CH' led will be on. The 'OK' LED will be off. In this pic the 'CC/CV' LED is red and on dimly, the blue 'CH' LED overwhelms the camera:

In the middle part of the charge the current into the cell will fall under the 1A limit, the 'CC/CV' LED will turn off, middle 'CH' LED stays on.

Near the very end both 'CH' and 'OK' will be lit together:

When the charge current falls below the set point and cell voltage has risen to the voltage set point, the 'CH' LED will turn off, with only the 'OK' LED on:

The cell isn't completely finished at that point, but, since output voltage can never go over your setting, if you set it to the correct voltage it should be ok to let it run like that basically forever, I suppose. For a 4.30v setting if you remove the cell as soon as the 'CH' light turns off, cell's resting voltage will be around 4.26-4.27v. Another 15-20 minutes will bring it up to 4.29-4.30v.

Thanks comfy! I'm really tempted to try and adapt this module into a cheap charger, but I know it would be forever before I'd get around to it with so many mods sitting and waiting.

-Garry

My idea would only work for a single bay charger, right? What would happen if you charged two in parallel but the batteries had different voltages? Would it still work for that?

-Garry

If you put two batteries in a parallel box current will flow from the higher voltage one to the lower, whether you are charging them or not.

This board would do multiples in parallel, just crank up the amperage. But they all have to be fairly close to the same voltage at the start. I always charge LiIons in parallel or as singles, I don't have the patience to sort through everything needed to mess with balance leads and adapters and whatnot to do series charging.

Yeah I didn't even think about the higher voltage cell charging the lower voltage cell (by itself w/o charger even connected). Guess that's not a real good situation. Better stick to a single cradle charger then. Problem is, I don't know if the cheap chargers have enough room inside for the module. Here's the single bay one I was looking at for a "host".

-Garry

The thru-holes (if they are that) on the far right that appear to be labled B1, B2, B3, ?. Are they for balance charging cells in series?

No, this thing doesn't even shut off when finished. My board has the same components in the same locations but the PCB is different, mine has no holes outboard of the indicator LEDs. There's not enough parts on there to do anything like balance charging.

Oh, so they are for remote indicator LED's?

I have no idea, I don't have one with those holes. But a board with a single LM2596 chip and a few indicator LEDs isn't capable of doing balance charging.

Awesome thread! I really appreciate all the work you guys put your posts.

After playing for a few more hours I think a better way of adjusting the CH to OK transition point is to just ignore the CH adjustment and monitor the cell voltage, when it's finished and voltage has reached your set point then adjust the CH pot.

At any point during the charge you can mess with the CH (middle) pot without affecting anything other than which LEDs are on. Starting from fully CCW, turn the CH pot clockwise until the CH light turns off, then a little back CCW will turn on both CH & OK at the same time. As more charge goes into the cell the voltage rises and the current decreases, and gradually the CH light dims and the OK light brightens. Turn the CH pot a little further CCW and you'll get both CH & OK lights again. Keep chasing it like that and at the end of the charge you'll have a feel for the setting that'll be closer to accurate for indicating the charge is actually complete.

They are so proffesional. :heart_eyes:

I just got mine. They look good on the surface. Now to decide what to use them for.

those look perfect for driving a couple of these for some diy cabinet / shelf lighting

speaking of these lights has anyone seen anywhere other than dx that sells them?