Soshine SC-S2




This is a two channel 18650 LiIon charger with some smart features.


I got the chargers without any accessories or box, only a standard 12V volt power adapter was included. The adapter has US plug but is universal voltage.




The charger has one connection, it is for 12V power, either the supplied adapter or a car adapter can be used to supply power.



There is a two color led for each of the two charger channels:

• Off: No battery in charger
• Red flashing: Error.
• Red/green flashing: Battery voltage to low
• Steady red: Charging.
• Green flashing: Charging nearly complete (Only 10-20 minutes left).
• Steady green: Charging complete.

The charger can handle 70 mm long batteries, and both button and flat top cells.
The charger is only rated for xx650 batteries and can only hold that size, but adding a spacer makes it possible to charge xx500 batteries.


Measurements

At low voltages the charger will charger with a low current (4.4mA), this will reset any tripped protection.
Between 1.56 volt and 3.72 volt it charges with 180 mA. This is designed to soft charge empty batteries, but the 3.72 is way to high.
Between 3.72 volt and 4.2 volt the charger is applying regular charge current with constant current, when 4.2 volt is reached it uses a constant voltage charge.
The charger stops when the current has dropped to about 200mA.
When the battery goes above 4.2 volt or the charge stops the current is turned off (discharges with up to 220 uA current).
The charger will restart if the battery voltage goes below 4.1 volt, the power has been interrupted or the battery is replaced.
When charger is disconnected from power, but with a battery in, it will draw about 2.2 mA from the battery (This is shared between the two batteries).
The green led start blinking when charger current is down to 350mA.



The charge curve is CC/CV, but most of the time the charger is charging with reduced current, first when the battery reach 3.72 volt will it charge with (about) 1A. This makes the charge time about 10 hours for a 3100mAh battery.
This looks like the charger tries to implement the full LiIon charging algorithm, but got the threshold voltage wrong (somewhere around 3 to 3.3 volt would be much better).



The current and voltage is slightly different for the second channel.



Charging on both channels at the same time and measuring on the first channel, it looks exactly like when only the first channel is used, i.e. the channels are fully independed.



This time I have charged a battery with a higher voltage and the charger will engage full charging current earlier



Using an old battery that cannot keep the voltage above 4.1 volt, the chargers keeps restarting the charge cycle. The CC/CV profile is also somewhat distorted.



Conclusion

This charger follows a CC/CV charging profile and also supports long 18650 cells. It also has the smart feature with the flashing green lamp, when the battery is nearly charged.
The above could make the charger one of the best one the market, but it has a few details that spoil it: The slow charge speed and the termination current is a bit too high. The slow charging speed just requires patience and the termination current means that the battery is a few percent below maximum capacity.
I do like the charger and hope Soshine will fix the 3.72 volt threshold.



Notes

The charger was supplied by Orbtronic for review.

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