CottonPickers Dual 4.2V-4.35V


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 for some special LiIon batteries (LG 18650 D1 3000mAh (Pink) and Sanyo UR18650ZTA 3000mAh (Magenta)), but can also charge normal LiIon batteries, depending on a switch setting.

DSC_3104 DSC_3113

I got the charger in a nice box.


The charger is delivered with two sets of wires, one with alligator clips and magnets and one set with magnets only. A car charger was included and a instruction sheet was also included, it contained warnings about the 4.35 volt mode (It must never be used on a 4.2 volt LiIon cell).
Together with the charger I also got a battery tray (This must be ordered seperatly).

DSC_3118 DSC_3119
DSC_3120 DSC_3122

The charger is usb powered and need a usb port that can supply 1A when charging 4.35 volt cells. The switch is used to select between 4.2 volt and 4.35 volt and as an extra warning the symbol for 4.35 volt is a skull and crossed bone. The voltmeter is 3 large red digits.


There is a red led behing the bump it will be brightly lit when charging to 4.2 volt and weakly lit up to 4.35 volt.
Without a battery connected it will be lit.


The charging leads or the tray is connected to the small connector.

DSC_3115 DSC_3116

I used the tray for my tests. It can fit any 18650 between 65 and 70 mm in length.
When a battery is put into the tray the red led on the tray will be lit.


supportedBatterySizes DSC_3402 DSC_3404 DSC_3405

With the magnets the charger can be used for many LiIon battery sizes.


The charger is basically two 0.5A chargers in parallel, one 4.2 volt and one 4.35 volt, the switch will enable or disable the 4.35 volt charger.


The first curve shows the reason to get this charger (4.35 volt charge). The current trace look at bit special between 150 and 175 minutes, it is when it reaches 4.2 volt and only the 4.35 volt charger is left. The termination is around 30mA.
Generally I will call it a CC/CV curve, but with a slow change from CC to CV, it means longer charge time, but will have no ill effects on the battery.


A normal 4.2 volt charge does also use CC/CV and 50mA termination





Even my old IMR16340 is handled perfectly.


The charger is a good 4.35 volt charger and does also work well 4.20 volt. I will only recommend the charger if there is a need for 4.35 volt charging (A wrong switch position for a 4.20 volt battery is not good).


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