Charger Efest SODA 2014

This is an updated review of the SODA charger, because Efest has adjusted the charge voltage. When possible contents has been reused from the old review.





Efest has been building a line of chargers from single cell to four cell with fixed and variable current, this is a fairly simple two cell LiIon charger.



The charger comes in a transparent plastic box. There is no doubt about the contents of the package, the charger and a mains cable.



On the back of the box are some specifications. With the update the charge voltage has been adjusted from 4.23 volt down to 4.2 volt.



The charger can be powered from mains or from 12 volt, there is also a current selection switch.
The placement of the switch is not ideal, I would have preferred having some indication on top of the charger, about the charge current. Either the switch or a led.



There is a charge indication on top of the charger, it is at the bottom (minus) end and is the usual red/green leds. They are red when charging and green at other times.



The sliders for the battery works smoothly and can accept batteries from 30mm to 71mm.



On top of the charger is a list of supported battery sizes, but it does include some batteries that are too small to charge on the charger and it is missing a list with current settings.





The charger can handle 70 mm long batteries including flat top cells.
Because the 0.5A current is more like 0.6A, the charger is not that good for 16340 batteries (except IMR). It is even worse with 10440 batteries, it is only a good idea to charge IMR 10440 on it.
Note: Using to high charge current will not make the batteries explode, but will reduce lifetime of the batteries.



Measurements

• When not connected to power it will discharges with up to 0.4mA.
• When power is connected with a full battery, the charger will discharge with 0.04mA
• Below 0.4 volt the charger does not detect a battery and does not charge.
• Between 0.4 and 2.9 volt it chargers with up to 50mA current (Led is red).
• Above 2.9 volt it will charge with full current.
• It will restart charging, if the voltage drops below 4.14 volt (See KP14500-08 curve).
• It will not restart charging on reinsertion of the battery or power cycling.
• It is possible to switch current during charge.
• The channels on the charger are independent, i.e. there are small differences between them.

The charger does a fine CC/CV curve, but the termination current is a bit high.
The charge voltage has been adjusted and is at 4.20 volt.



The second channel is the same, but due to the high termination current the charger restarts a few times.




Other capacity cells takes more or less time, depending on capacity.



Surprisingly the charger handles my old IMR cell with rather high internal resistance very nice.



The 18350 cell looks more like I expected with the high termination current



Using the 0.5A charge current does not change the termination current.
The 0.5A current is more like 0.6A, making it slightly to high for 16340 batteries.



Also at 0.5A the old IMR cell is done nicely.



The 18350 is charged without any funny stuff at 0.5A.



With the 14500, the charger restarts a couple of times, again due to the high termination current.



Charging with 12V DC supply looks a bit strange, instead of slowly reducing the current it drops to 0.5A and then goes into the CV phase a bit later. There is nothing wrong with this, except it is a bit slower.



As with most chargers, there is generated a lot of heat when charging.



M1: 47,4°C, M2: 46,7°C, M3: 57,3°C, HS1: 84,1°C

There is something inside the charger that gets very hot.



M1: 54,0°C, M2: 55,5°C, HS1: 64,9°C



The charger starts up very fast and goes to full charge current.


Testing with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



Conclusion

The charger charges with the correct algorithm, and the two current selections makes it possible to charge more battery sizes, but I could have wished for a slightly lower low current.
This charger is good for 18650 cells, but the high termination current means that especially smaller cells will be some percent short of a full charge.



Notes

The charge was supplied by Efest for review.

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