SODA Dual Battery Charger 2017





This is a dual cell mains and 12V powered LiIon charger with a switch to select charge current.



It arrived in a small cardboard box with specifications on it.



The box included the charger, a mains cable, a warranty card and the instruction sheet.



The charger has a mains socket with universal power (100-240VAC 50/60Hz) and a 12V DC connector.
The current selector is placed between the two power input.



The only user interface is a led light for each channel, it is red when charging and green at other times.



Specifications are on the bottom.



The slots uses the classical slider construction and it works fine.
The slots can work from 29 mm to 70.2mm. This will give problems with long protected xx650 batteries.







The charger can handle 70 mm long batteries including flat top cells.



Measurements

• When not connected to power it will discharges with less than 0.3mA.
• Below 0.8V the charger will not detect a battery
• Between 0.8V and 2.9V the charger will charge with about 50mA to 100mA
• Above 2.9V the charger will use regular charging.
• Charger will restart silent when voltage drops slightly.
• It will restart charging on reinsertion of the battery or power cycling.
• Power consumptions when idle without battery is 0.4 watt in 1A and 0.3 watt in 0.5A setting.
• From 12V it need 19mA when idle without battery in 1A and 15mA in 0.5A.

The charger uses CC/CV charge algorithm and charges to 4.2V, but it is not terminating this time (I might do it later).



The second channel terminates slightly below 100mA



Here I am chargint at 0.5A and the channel terminates nicely.



Again a missed termination.



And a perfect termination.



This old cell is also terminated perfectly.



But on this smaller cell it misses termination.



And the very old and nearly completely worn out cell it terminates fine, at a very low current.



No problem with two cell at a time.



Running it from a 12V supply it can be seen that it needs about 0.9A for charging two cells.



M1: 47,2°C, M2: 47,6°C, M3: 61,0°C, HS1: 88,9°C



M1: 59,4°C, HS1: 65,3°C




Sweeping the battery voltage from zero to 4.25 shows charge current at the different charge levels.
I did also add a curve to show how much heat is generated in the charger, most of the time the voltage will be between 3.5V and 4V, i.e. just below 3 watt with one cell at 1A.



The charger needs about 3 second to start.



Current can be changed at any time.

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



Conclusion

I do not like the very discrete current switch, I want some easy to see indication with selected charge current.
The missing or more likely late termination on some cells means it is best to remove batteries when they are charged.

I will only rate it acceptable, due to the termination or lack of.



Notes

The charger was supplied by Efest for review.

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