Review of Charger CottonPickers Basic 100mA

Batteries and Chargers Chargers
1

Charger CottonPickers Basic 100mA



CottonPickers has been making chargers for a long time, mostly he sells them on cpfmarketplace, but you can also sometimes find them in webshops. This model here is the smallest and cheapest version, or would have been if I had selected "silver" instead of red. You can get this charger with a couple of different charge currents, I have selected the lowest standard current (i.e. 100mA), the highest current is 700mA for this model.



I got the charger together with an general instrution sheet.



Notice the small hole just outside the label, there is a red led behind this hole.
This led is red while charging and flashing red when power is connected but no battery.





The charger is practial, but the finish is not perfect.




The battery connection is with magnets, this means the charger can be connection to any size battery, but for larger batteries a lot of patience is neaded with a 100mA charge current.



The charger can be used for many sizes of LiIon cells, but due to the low charge current and termination current it is best suited for cells below 500mAh to 1000mAh.



Measurements

  • Without power connected there is about 1.2uA current draw from the battery.
  • With power connected there is also about 1.2uA current draw from the battery.
  • Below 2.9 volt the charge current is 14mA, above it will charge at full current.
  • Power cycling or battery reinsertion will not restart charging.
  • The charger will restart when the battery voltage drops to 3.9 volt.





With 100mA charge current I did not want to test any larger batteries, I stayed with the smaller sizes.
The 18350 get a perfect CC/CV charge, with a termination current of 10mA.



My old IMR16340 cell did also charge perfectly



Conclusion

The charger does a very good CC/CV charge and is very good for charging small LiIon batteries in the 100mA version.
I do not expect the higher current models to have the same nice CC/CV, they will probably run at reduced current the first part of the charge cycle (Due to heat).


Notes

Here is an explanation on how I did the above charge curves: How do I test a charger

2

Interesting charger.
Thanks for the review!

3

Thanks. Nice, 100mA, a great option for charging 10440.

4

I’d like to see what chip it uses. Especially with its nice charge curve unlike the soft CC/CV of some other (chinese) chips.

5

It might be related to the low charge current.

Try checking the LIPOnano, the 0.5A curve does not look nice, but the 0.1A looks very good.

6

It feels like the sot23 mcp73831 & pcb in the LipoNano just doesn’t provide enough heatsinking for 500mA. The CC to CV transition is still nice & sharp at 500mA. The DFN should really be used for 500mA since it has a center thermal pad.
The tp4056 or tp4057 on the other hand slides into the CC / CV transition, heatsinking or no. In the ML-102 the transition might be worsened by one of the tp4057 changing to CV before the other.

Given a choice I’ll take a sharp ‘perfect’ transition & have it finish the charge slightly sooner. MCP73831 for 10440, mcp73833 for higher currents.

7

I do not agree, on the first charge curve, in my review, the current start to drop when voltage is at 4.03 volt.

Heat is often a problem with these small charger chips, they need some external heatsink to sustain full current.

8

They needed to use the DFN package in order to properly go for 500mA. The DFN version might be less available to them.

Hmm, I see that on your curves now.