Charger Xtar MC1





Xtar makes many LiIon chargers, this is their smallest charger that can handle 18650/26650 batteries. The charger is small and light weight, it can only charge one battery at a time and only with 0.5A.




I got the charger in a small cardboard box with the specifications printed on it.



The box contains the charger, a usb cable, a instruction manual and a warranty card.



There is no power supply included with the charger, you must supply your own usb power supply/charger. With a maximum charger current of 0.5A the charger can run will most usb supplies (Some of the cheaper ones does not supply specificed current: See my test).
The connector is micro usb, i.e. most mobil phone chargers can be used.



There is not much user interface on the charger, only a red/green led. It is red while charging and green at all other times.



The charger can handle both button top and flat top batteries.
The slider moves smoothly and can hand cells from 31mm to 72 mm long.





The charger can easily handle 70 mm long batteries, including flat top cells. (See my small LiIon comparison for length of different brands).
The current is to high for 10440 batteries.


Measurements

• Below 2.9 volt the charger charges with about 70 mA (Red led is on).
• Above 2.9 volt the charger applies regular charge current.
• When the charge is finished the charger is charging with a few uA.
• The charger will restart if the voltage drops below 4.12 volt, but the led will first indicate charge if the voltage drops below 4.09 volt (This probably depends on the actual reference voltage of the two charge chips).
• Power cycling or battery reinsertion will not restart charging.
• When charger is disconnected from power, but with a battery in, it will draw about 25 uA from the battery.
• Charger has two parallel charging circuits.

In the first curve I have both measured the charge curve, the input current and the temperature. With only 0.5A charge from 5 volt, there is not much heat in the charger.
It does a fairly good CC/CV, it is slightly below maximum possible speed, because the charge current drops slightly when battery voltage raises and it changes to the CV phase a bit early. The termination current is around 40mA, but the charger reports battery full at about 130mA.
It will probably be random what charge circuit finish first, i.e. on half the chargers the led will be correct.



A 3400mAh battery takes longer to charge.



And a 2600mAh battery is faster to charge



No surprise with the 18350 cell.



Even my old 16340 cell is charged perfectly.



A 800mAh 14500 cell.



The charge current varies slightly with input voltage, i.e. a usb supply that can deliver stable 5 volt will mean slightly faster charging than one that drops to 4.5 volt.
The charger can supply 0.4A with about 0.6 volt drop in the charger, this can also be seen in the charge curves, it maintains nearly full charge current until the battery voltage is above 4.1 volt.



M1: 27,5°C, M2: 26,1°C, M3: 27,2°C, HS1: 28,7°C
With only 0.5A charge current, there is not much heat in the charger. This is very good.



The charger is a simple charger and does not need any time to initialize when power is turned on, it simply starts charger with 0.5A.



Conclusion

For a simple and light weight charger, this is a good charger.
The charge indication led may report finished before the battery is full, but it is usual only a few percent charge that will be missing.



Notes

The charger was supplied by XTAR for a review.

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