Review of Charger Xtar XP1

Batteries and Chargers Chargers
1

Charger Xtar XP1



Xtar made many good chargers, this is a new small charger. It has a single channel and can charger both LiIon and NiMH batteries up to AA size.




It comes in a cardboard box with specifications on the back.



I got the charger, a manual and a usb cable.



The control panel has 3 leds and one button:
2 Leds to show selected current (0.25A or 0.5A).
1 leds to show charge status for the batteries (red=charging, green=done or no batteries).
The button will select charge current, when power is connected and a long press will activate cycling with a NiMH (Not with LiIon).



The power input is a micro usb connector, i.e. any usb power supply/charger can be used.



Xtar has a special label on, that makes it possible to check for counterfeig chargers.



The charger can handle both button top and flat top batteries, from 31mm to 52.8 mm (i.e. from CR123 up to AA size). The slider works very smooth.








The charger can handle 52.8 mm long batteries, including flat top cells. (See my Small LiIon comparison for length of different brands).



Measurements charger

  • Charger uses a buck circuit, i.e. it uses less current from usb, than it charges with.
  • When power is disconnected it will discharge 1.5 volt batteries with 20uA
  • When power is disconnected it will discharge LiIon batteries with 60uA
  • Will charge LiIon with 150uA after termination.
  • Will charge 1.5 volt batteries with 10mA after termination.
  • Will restart LiIon charge, if voltage drops below 3.90 volt.
  • Will restart charge on power cycle and reinsertion of battery.
  • Will detect at battery at 0.14 volt and start charging.
  • At about 1.9 volt it will switch to LiIon charging.




This charger has a very good CC/CV curve, the termination current is slightly high.



My old 16340 is also charged fine.





250mA or 0.25A works just as good, just slower.



During startup the charger has a periode with low charge current, my guess it that it is used to detect battery type.



Increase in charge current is done with a slow ramp.



NiMH batteries




The charger does some pulsing while charging NiMH, it looks like the termination is a -DV termination.
When terminated the charger will trickle charge, this is a good idea with NiMH (But prohibited with LiIon)



Using 0.25A charge current is not a good idea for AA batteries, the charger has problems detecting when it is done.



With AAA batteries at 0.25A charge current, the termination if detected earlier, but it is still not perfect.



It takes 60 minutes to detect a full AA battery at 0.5A, not very good.



Holding the button down with a NiMH battery in the charger will start a refresh function, where the battery is first discharged, then charged.



The current selection is not used during discharge, only during charge.



With a NiMH battery in the charger, it stays at the low current for about 2 minutes, before going to full charge current.



During NiMH charge it will stop charging each other second, this is probably done to check the voltage.


Conclusion

This charger does a good CC/CV charging on LiIon and with 2 current settings it can handle a wide varity of small cell sizes.
The NiMH charging has some problems with termination, making the termination a bit more sensitive and only allow charging at 0.5A would probably be a good idea.

The charger is a very good LiIon charger and a acceptable NiMH charger.



Notes

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

2

Thanks for the review! Wow, takes a long time to detect Ni-MH. Over twice as long as Soshine SC-F3.

3

Thanks for the review!

Sounds like a nice little charger considering the price and all..

4

I definitely can’t find a proper need to have this charger. Why only up to 18500? Why would I want to charge my NiMhs as singles? Why such a dedicated charger for small works, why not adding LiFe support?

Looks like a quality one, though. Ok, it’s only a USB charger, but still…

5

Good if you use a Sipik sk68 or similar with 14500 and AA cells. If you’re using single cell lights it could be a handy travel charger.

6

If your normal travel kit only uses small LiIon batteries and maybe a AAA in addition to a mobil phone, this charger will fit very nice.

7

Do you think it is best only to use it with AAA NiMH?

8

No, but do always use the 0.5A setting for NiMH, both AA and AAA works fine with that.

9

Only if I modded my SF L2m to accept a 18500, then I guess I could, but still, I have ML102 single 18650 charger. I could happily accept this one if it were a bit longer to accept 18650s too.

10

Thank you HKJ, awesome review as always.

Please tell us Xtar XP4 Panzer also in progress :wink:

11

Not yet.

12

Great Review. Thank for the nice work.
I am currently using it. Wondering why I bought it for in the first place too. Without reading you review first.

13

How can the LiIon restart the charge, if there is a trickle charge of 150uA for maintaining the 4.20V? With this trickle charge, the voltage will stay 4.20V constant and never drop below 3.90V?

So Eneloops get a 10mA trickle charge after the ~1.5V termination? :)

14

I do not expect it will ever happen, but this not prevent me from checking it.

Generally chargers does not need a restart function, even without any leak current from the charger, the battery will last for years, before it drops below 3.9 volt.

Cottenspickers chargers with voltmeter is a different case.

Yes, this works nice to keep old NiMH charged.

15

So the XP1 uses 10mA trickle charge. Hmm.

As a general rule, which range of currents (mA) would you believe to be reasonable for trickle charge?

Would 300mA be too high in your opinion? Wouldn't 10mA be too low? Don't you agree that anything between 50—300mA would be optimal? :)

16

Trickle charger must be under 0.1C, i.e. for a 2000mAh battery it must be below 200mA. The 0.1C is the standard charge current used for a 16 hour charge when testing capacity. 0.1C can also be used to balance battery packs with NiMH in series.

For trickle charging I would expect a range from 1mA to 50mA would be usable, the 50mA is enough to compensate for a AA that self discharges in two days or a D that self discharges in 8 days.

For chargers with a weak termination algorithm, a extra charge of one or two hours at 0.1C can be used to compensate for that.

17

I see, trickle charge should be dependent of NiMH cell capacity and <0.1C, good to know!

Thanks for your opinion, appreciated! :)

Similar info is given on BatteryUniversity page.

18

Does the xp1 have similar problems with the badly soldered usb as the mc0?

19

Nope. My copy of the charger is fine and of good quality. However, it is being phased out. If i m correct.

20

Probably a dumb question, but would connecting the provided USB cable from the Xp1 to a 5V—1A output block (i.e. one used for iPhone charging) cause any issues? The specs say it needs 5v — .5A input.