Charger CoilMaster Smartcharger A4

DSC_0067

DSC_0068 DSC_0069

This is a simple charger that is specialized for 65mm long batteries, i.e. unprotected 18650 and 26650 LiIon cells.

DSC_0041 DSC_0042 DSC_0043 DSC_0044

The charger comes in a cardboard box with specifications on the back.

DSC_0062

The pack contained the charger, a power supply and a instruction sheet.

DSC_0071

The charger has a 5V input that is used with the supplied power supply.

DSC_0064

The power supply can supply a lot of current.

DSC_0110

The user interface is 4 red leds for each battery, they will be animated when charging and all four will be on when battery is full. The leds are not very bright, i.e. they are difficult to seen in sunshine or bright light.

DSC_0072

The charger has two different charge current depending on slot used and this is marked in the slots.

DSC_0073 DSC_0074

The charger has a fixed length slot and it fits unprotected 18650 and some 26650 cells (only center slots). The problem with 26650 is the button top that some cells have, there are not space for that.

supportedBatteryTypes

supportedBatterySizes DSC_0106 DSC_0107 DSC_0108



Measurements on charger


CoilMaster%20Smartcharger%20A4%20%28SA18650-33%29%20%231

The charge curve is a nice CC/CV, but it never terminates, this is not the best charger behaviour. The current is supposed to be 1A, but it only 0.56A

CoilMaster%20Smartcharger%20A4%20%28SA18650-33%29%20%232

This is a 2A slot and the current is 1.1A

CoilMaster%20Smartcharger%20A4%20%28SA18650-33%29%20%233

There is a some oscillation when the charger goes from constant current to constant voltage on this channel.

CoilMaster%20Smartcharger%20A4%20%28SA18650-33%29%20%234

Channel #4 is about 0.6A

CoilMaster%20Smartcharger%20A4%20%28SA18650-26%29%20%231
CoilMaster%20Smartcharger%20A4%20%28PA18650-31%29%20%231

These two cells get charged fine, but it is the users responsibility to remove the batteries when they are full. Within a couple of hours in fine. Leaving them longer will mean increased wear on the cells.

CoilMaster%20Smartcharger%20A4%20%284xSA18650-33%29

Charge speed is the same with four cells.

CoilMaster%20Smartcharger%20A4%205V%20%284xSA18650-33%29

The charger needs about 3.5A at 12V when charging 4 cells, again the oscillations can be seen.

Temp4331

M1: 37,3C, M2: 41,4C, M3: 41,6C, M4: 38,3C, M5: 40,9C, HS1: 53,3C

Temp4332

M1: 36,5C, M2: 40,1C, M3: 40,4C, M4: 37,5C, M5: 39,4C, HS1: 48,5C

Poweron

This charger is rather simple and will start in less than a second.

CoilMaster%20Smartcharger%20A4%20PS%20load%20sweep

Usual I do not bother checking the supplied power supply, I just assumes it can deliver the power. In this case the charger is using considerable less current than expected and I wondered if the power supply was below rating.
It is not, the output voltage drops a bit with load, but not much and the efficiency is very good.


Testing the charger with 2830 volt and 4242 volt between mains and low volt side, did not show any safety problems.



Conclusion

The idea of a simple xx650 charger may be good enough, but for this one I have a couple of complaints:

I will rate the charger acceptable.



Notes

The charger was supplied by CoilMaster for review (I have checked two chargers, both used about the same charge current).

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