Test/Review of 2S 3A LiIon charger TS-2012H

2S 3A LiIon charger TS-2012H



Official specifications:

  • Input: 110-240Vac 60/60Hz
  • Output: 8.4V 3000mA DC


This charger is for battery packs with 2S2P (2 in series 2 in parallel) or 2S3P or more parallel LiIon cells. The battery pack is supposed to contains its own protection and balancing.



I got the charger in a simple cardboard box.



Contents was the charger and a couple of different mains plugs.




It is fairly easy to replace the mains plug.





The led is a two color led, it will show red when charging and green at all other times.



Measurements

  • Connector is 5.5mm/2.1mm
  • Idle power consumption: 0.31 watt
  • Unloaded voltage 8.47 volt
  • Charger has no short circuit protection, the current will be above 10A when shorted.
  • Above about 0.9 volt the output current is limited and the red led will flash.
  • Will start charging at 3.9 volt.
  • Led shows green when only connected to a battery, but not mains
  • Green led is on when connected to mains, but not a battery.



Testing with 4 cells means a 2S2P pack.



The charge curve is a CC/CV, but the charger never stops, it just reports battery full (Green led) and continues to charge.



Same curve as above, I have just replaced capacity with efficiency, it is at about 80% during charge.



In the above curve I simulated a battery voltage from over discharge to fully charged. The charger is good at maintaining a constant current. The charger do not have a short circuit protection, but will limit the current from 0.9V to 3.9V!

During a charge I took IR photos at regular intervals of the hottest part of the charger:


M1: 62,1°C, M2: 44,7°C, HS1: 74,4°C
HS1 is the transformer.



M1: 39,7°C, M2: 58,3°C, HS1: 70,3°C
The fairly warm side is the heatsink on the rectifier diode, the actual hotspot is where the diode is mounted.



The charger starts fast a charges with a steady current.



Tear down



As usual the charger could be opened by putting some pressure on it.



Being a battery charger and not only a usb charger it needs a bit more parts on the low voltage side.
At the mains input it has a fuse, bridge rectifier (4 diodes below capacitor), capacitor and a common mode coil. There is also the switch mode controller with a heatsink and optical feed back.



From this angle the rectifier diode on a large heatsink is easier too see.



The loop covered in black tube (RS1) is the resistor used for measuring and adjusting the charge current.



This side is mostly used for the rectifier diode heatsink and the common mode coil. The yellow tape around the heatsink is for voltage isolation, because the heatsink is connected to the low voltage side, but is very close to some mains connected parts.



On the bottom the charge controller (A dual opAmp) can be seen, it is measuring the voltage accross the RS1 resistor and using the IC2 opto coupler to control the mains switcher.





There is a good isolation distance.


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



Conclusion

This type of charger is not nearly as advanced as single cell chargers. With only two wires to the battery pack it is impossible to do any balancing. The charger has a couple of issues: It is missing short circuit protection, it will slowly discharge the battery without mains connected (Will drain the battery in a few weeks) and it never turns the charge current off.
Calling it a 3A (3000mA) charger is also a bit optimistic, 2.5A is more correct.
The replaceable mains plug can be useful for traveling (If you can keep track of the plugs).


I will give this charger an acceptable rating.



Notes

The charger is from ShenZhen TengShun Power Supply Co.,Ltd, I got it with the help of BLF/MTBR user Ledoman.

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

Thanks HKJ for the reviews of these 3 2S2P Li-Ion chargers! (These reviews are likely being read more by MTBR members due to ledoman's quest to find a good higher current 2S2P charger.)

One question, how bad is it that these chargers do not terminate charge completely? Are they still safe? How long beyond "full charge" (i.e. green LED lit up) would you have to leave the battery on to really be at risk of overcharging?

Thanks!
-Garry

They do not over charge in the sense that it gets dangerous, but maintaining the battery at full voltage will wear it down considerable faster than without continues charge current.

That is the reason that charge chips (and many chargers) are made to turn the current off when full and then start a recharge cycle if the battery drops to much.

So the fact that the charger does not stop charging completely is still "safe" just not "ideal". So leaving it on overnight (or for a full day if one forgot about it) would still be ok. Many of the guys (& gals too for that matter) over at MTBR are not going to be as strict and safety conscious with li-ion charging as BLF users would be, so I just want to make sure these chargers are safe for "non-flashaholics".

Thanks,
-Garry

HKJ, would not most, if not all “wall wart” style chargers operate this way, i.e. no absolute cut off?

Guessing only hobby chargers or those designed to handle loose cells have the ability to switch off the current and then go into recharge cycle as you describe.

Thanks!

A device designed as a charger is supposed to include real termination, but it looks like battery pack chargers are missing it (My sample is rather small, only two brands).

Hobby chargers do not include automatic recharge.

I see that my XTAR VC4 does terminate the charge at 4.2V for each cell, and according to the manufacturer, begins recharge when voltage falls below 3.9V.

Guess when charging batteries in packs it really does pay to keep an eye on the indicator LED.

It is my understanding that in the past those chargers were designed to charge welded packs with protection circuit. So the safety issues are solved elsewere.I haven't seen that type of charger that would have cut off, even Magichine works like this. Don't know for higher priced brands.

Wearing out is also not a big issue if you think you are going to use pack 50 times a year (average user very likely even less). This would give you 500 charges in a 10 years. The batteries would be worn out very likely because of age and not because of charge cycles. All in all 5 years is the optimum usage time. In practice it is more important to store batteries half charged when not used for a longer period than to take care of fully topped charge.

Protection circuit in a battery pack would not fix it.

How fast the pack wears out depends on how many hours you charge on a full pack, if you use the pack every "day" and charge it every night it will probably wear out in considerable less than 5 years.

I do ride a bike daily (not MTB) and every winter I do charge batteries every night, this is more than 50 times in a year. I have used a battery pack some years, but it is more convenient to use a light with build in batteries and I do not need as much light as a MTB on a bumpy path.

Yes I know, it won’t fix wearing out. I just wanted to explain why they were designed so. And then they probably didn’t even think about wearing out.

Still in practice for an average MTB user this won't be a big issue as the one would probably buy new packs from time to time with higher capacity for more powerful lights we get spoiled on. But technicaly speaking you are right.