USB LiIon Charger BH-042100-02U

DSC_9008

DSC_9010 DSC_9009

This is a cheap LiIon charger from Ebay, does it work?

DSC_9007

I got the charger in a envelop from Ebay dealer: buybtyhere
It included the charger and a thin USB cable.

DSC_9011

The USB power connector is placed on the back of the charger.

DSC_9013

The user interface is a led for each slot, it will show red while charging and green at all other times.

DSC_9012

The back has the usual label with specifications, but they are not very precise.

DSC_9014 DSC_9015

The connection are the common slider style that can handle from 31.5mm to 69.5mm, this means a few protected 18650 will not fit and the new xx700 will not fit.

supportedBatteryTypes

supportedBatterySizes

DSC_9640 DSC_9639 DSC_9638 DSC_9637 DSC_9636 DSC_9635

The charge current is on the high side for small batteries and of course the voltage is too high for all batteries.




Measurements charger

USB%20charger%20BH%20%28SA18650-33%29%20%231

The charging is a rather bad CC/CV charge curve around 600mA and the charger never terminates, instead it charges to 4.3V. The charge circuit goes into oscillations at one point during the charge (This is probably a combination of voltage and internal resistance of the battery and do not show up on my other curves).

USB%20charger%20BH%20%28SA18650-33%29%20%232

Slot #2 is similar, but it do not oscillate, it is slower to charge and have a lower termination voltage, but still way to high.

USB%20charger%20BH%20%28PA18650-31%29%20%231

I did not try with a lot of batteries, due to the high voltage. This cell was charged in a similar way to the above.

USB%20charger%20BH%200.5ohm%20%28SA18650-33%29%20%231

Simulating a long cable or a weak charge do not affect the charger much

USB%20charger%20BH%20%282xSA18650-33%29

The charger maintain same charge speed with two batteries.

Temp7040

M1: 34.2C, M2: 35.2C, M3: 44.5C, HS1: 49.9C

Temp7041

HS1: 45.6C

Voltage%20sweep%200-4.40V%20%231
Voltage%20sweep%200-4.40V%20%232

There is a constant current generator for each slot inside the charger, it will use a low current for fully discharged batteries.



Tear-down

DSC_9641 DSC_9642

What is inside this type of cheap charger? The bottom was five screws and the circuit board was one screw.

DSC_9643

Not much on this side, only two dual color leds and the battery connection.

DSC_9645 DSC_9646

DSC_9644

Not much on this side either, only one unmarked chip for each slot. Each chip has two resistors and two capacitors.

DSC_9647



Conclusion

This is not a very good charger, the main issue is the high charge voltage and the secondary issue is that it never terminates.



Notes

The charger was supplied by a reader for review.

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