Test/review of Charger Xtar SC2

Charger Xtar SC2











This Xtar charger looks like a simple USB charger, but that is a bit deceptive. It is a simple LiIon only charger, but it uses Quick Charge and will charge batteries fairly fast when used with a QC usb charger.







I got the charger in this packing with many languages and specification on the back.







The pack contained the charger, a USB cable and a instruction sheet also in many languages.







The charger is USB powered and can work on both a normal USB charger and one with Quick Charge support.







The user interface is four blue leds for each battery. All leds will be one when charger is empty or battery is full, when charging one led will flash and the other will show charge status.







The charger uses the typical slider construction with a metal rail and works smoothly from about 52mm to 76mm, i.e. the charger can handle long protected 18650/26650/32650 cells and it is not possible to charger shorter cells (With the charger current this charger uses this is a good design).











The charger can handle 76 mm long batteries, including flat top cells.

When supplied from a QC supply this charger is only for high current rated batteries.







Measurements

  • When not powered a LiIon will discharge with less then 0.3mA

  • When used with a QC charger the voltage will be 9V.

  • When charging two batteries the current consumption can be up to 2A from QC 9V

  • When charging one battery the current consumption can be up to 1.5A from QC 9V

  • Power consumption when idle is 10mA from 5V USB

  • Power consumption when idle is 7mA from 9V QC


Charging from QC supply



This is a fast charge at 3A and the termination looks fine with about 200mA termination current.



The other slot looks similar.



The 20700 high current cell is also charged fine.



With two batteries the charge current is reduced to 2A for each, this is still very fast.



M1: 45.3°C, M2: 45.7°C, M3: 60.3°C, HS1: 65.6°C
When charging at high current the batteries do get warm.



HS1: 69.1°C




Charging from 5V USB supply

Using the charger with a non QC supply will limit the charger current some.



A single cell is charge with 2A, but for some reason the charger terminates at 500mA, this is rather early and means that the battery is not completely full. This only happened once.



The second slot terminated at 200mA and this looks much better.



This time the charger terminated correctly at 200mA.



No problem with this cell, except a lower termination current would have worked better with it.



Even this old cell is charged nicely.



With two cells and non-QC supply the current is down to 1A for each battery, this means less than 2A draw from the supply.



Using a 0.5ohm resistor in series with the supply to simulate a long cable or weak supply did work, the batteries got charged, but the charging is slow.



Conclusion

This charger works fine, but it is limited to high current batteries. I would have been nice with more visible warning on the charger than the black 3.0A marking in the slots.

For the right type of batteries it is a good charger, but it will be hard on regular 18650 batteries.


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
Read more about how I test USB power supplies/charger

Thanks for the review HKJ. I wonder if this charger is replacing the MC2.

I doubt it. I think the SC2 is intended for high current batteries only. The replacement for the MC2 is the MC2 Plus, which increases the max charge rate to 2x1A.

SC2 is a fast charger, available with QC3.0 protocol, fast 2A×2 / 3A×1 charging. xtar website: http://www.xtar.cc/products_detail/productId=197.html

Hmm, it seems that XTAR will launch a MC2S replacing the MC2. :+1:

I noticed a strange thing. Chargers Xtar SC2 and Xtar SC1 when installing the battery produces voltage to the USB.

I believe that happens with some other chargers too in my experience (I also often connect a USB meter to simple USB-powered to estimate charging current is decreasing or not yet, ie. going to CV phase) … will have to check again which other USB-powered chargers have that too.

HKJ: it seems that this charger would be OK for lower current battery if supplied from regular 5V USB rather than a QC supply. Am I right? I have the charger and a low current battery, so I’ll test once I have discharged it.

Edit: so I have learned a few things. First thing: the protection circuit on this 18650 is probably not functioning properly, as it discharged to 2.55V (unloaded) without stopping before I caught it. This is at least 6 years old, so I suspect that’s too low. Memories stir of an Amazon recall notice many years ago relating to the torch this came with…

Second thing: as I already guessed, this torch (same age - ‘OxyLED MD50’) does not have a protection circuit built in.

I’m about to find out whether the Xtar SC2 charger will rescue the battery. I am using a standard 5V USB supply and it is charging one battery at about 240mA. Not sure whether it’s the supply (meaning SC2 is OK for lower current batteries if used with a standard USB supply) or a high impedance in this old battery.

I inserted my multimeter leads between the negative charger terminal and the negative terminal of the battery. I waited for the charger to recognize the battery, then touched one lead to the negative of the battery, then with the other lead, pushed the charging spring pad back, without interrupting the charging. (edit: I don’t know if my multimeter leads affect the measurement much. I have a Uni-T UT139C)

1A 5V usb charger (Samsung)
single cell (30Q)
0.30A measured

9V 1.8A / 5V 1.8A “fast charger” (LG)
single cell (30q):
2.8A measured, using the “2.5A” cable supplied with the charger
measured again at 2.2A
2.0A measured with a short unmarked cable. I let it charge for about 5 minutes, and the cable was a little bit warm, not much, but warmer that the other cable when compared. I suspect it is much safer to always use the cable that xtar provides that is marked “2.5A”.

5V 1.2A LG charger
single cell (30q)
0.56A measured

QC3 charger (ICAN 100w usb-pd and QC3)
single cell (30q)
1.8A
This charger should have a similar behaviour to the LG “fast charger” 9V 1.8A, however the xtar charges slower with it… (tested 3 times) This is weird. The lights on the xtar sc1 blink faster with LG “fast charger”, I thought it might mean that it

I will buy a dedicated QC3 charger to get the max performance. Also, I wish there was built-in way to reduce the charging speed to 1.5A or 2A.