Test/Review of Charger Xtar WP2h

Charger Xtar WP2h





This is the latest version of the WP2 charger. The other versions I have tested are WP2 II 2014, WP2s, WP2 II and WP2, most of them has been good chargers.
This charger has a few significant updates: It can do 3 currents and 3 voltages. This makes it suitable for many types of LiIon batteries. It can also be used as a usb power bank.




It comes in a cardboard box with a lot of specifications on.



The box contains the charger, a power supply, a car adapter (This might be optional), a warranty card and a instruction sheet.



The charger has a 12V input and a usb output.



The user interface is 6 leds, a button and a 3 position slide switch.
3 of the blue leds is used to show voltage and current selection, the last blue led is on when usb output is on.
The red/green leds show charger status: Red=Charging, Green=Not charging, flashing red=error.
The button is used to select current.
The slide switch is used to select voltage.



The slots uses the usual slider system and works fine, it can handle batteries from 31.8mm to 71.0mm.



The sliding switch on the charger is used to select nominal voltage.




The charger can handle 71 mm long batteries, including flat top cells.



Measurements

  • When not connected to power it will drain about 4mA from a battery in channel #1 and 0.5mA in channel #2.
  • Selected voltage is shown flashing on blue leds when no battery is present and charger is powered.
  • When charging blue leds shows selected current with a steady light.
  • Changing current or voltage will always be displayed on the blue leds for a few seconds.
  • The charger will charge with 2.8mA from 0 volt and not report any battery (led is green).
  • From about 1 volt the charger will report error (Flashing red led), if the battery stays low in voltage.
  • From about 2 volt the led will change to a steady red and apply about 45mA (80mA in 1A mode).
  • At 2.9 volt regular charge current will be applied.
  • Charger always starts with the 0.25A setting.
  • When charge is finished the charger will charge with 0.4mA.
  • Charger will restart if voltage drops to 3.9 volt (3.6V & 3.8V mode).
  • Charger will restart if voltage drops to 3.3 volt (3.2V mode).
  • Charger will restart charging after power loss, or battery insertion.





The charger does a nice CC/CV charge with a 100mA termination current.



At 0.5A charge current the termination current is down to about 50mA.



At 0.25A charge current it is down to about 25mA, this is very nice and means the charger will work well when charging smaller cells.




No surprice with different capacity. My 2600mAh cell enters the CV phase a bit early, this is both because it a 2600mAh cell and because it is a bit old.



The second channels looks like the first.



My old 16350 is charged fine, even at 1A.



Reducing the current to 0.25A will fill a bit more enegy into the cell, due to the lower termination current.




The two mid sized batteries is charged fine with 0.5A.



Doing two batteries at once does not affect the charge speed.



The charger uses slightly below 1A on the 12V input when charging two batteries with 1A each.



M1: 38,6°C, M2: 38,2°C, M3: 47,5°C, HS1: 65,5°C
As usual chargers gets very hot inside, this charger keeps an acceptable temperature on the batteries.



M1: 38,6°C, M2: 37,8°C, M3: 47,0°C, HS1: 48,8°C



The charger needs about 8 seconds to reach 0.25A charge current.



Changing current will slowly ramp up to the selected current.



4.35 volt charging (Switch position 3.8V)



There is no surprise with 4.35 volt charging, it looks very fine.


LiFePO4 charging (Switch position 3.2V)



LiFePO4 is also charged correctly.



USB output

  • Usb output only works from slot #1.
  • Press the button to turn on usb output when no power is connected to the charger.
  • Led shows green with fresh battery, red with partial discharged, flashing red when nearly fully discharged
  • When usb output is on and unloaded it will drain about 13mA from the battery.
  • Status led changes from green to read at 3.54V and start flashing at 3.18V
  • The status led is latching, i.e. battery must be removed to reset voltage status.
  • Output is not overload protected and will emit smoke at 2A load (Oops).
  • USB output is coded as Apple 1A




The usb output from the charger is very stable, but not overload protected. Making the above curve did blow the charger.
I.e. do never use a "charge optimizer" on this usb output.



Running at the rated 1A load the charger has very good efficiency and maintains the usb output voltage until the battery is empty.





Efficiency is even better at 0.5A load, the runtime will vary with the used battery.



The noise is very low with 1A load: 5mV rms and 55mVpp.



And about the same at 0.5A load: 5mV rms and 52mVpp.



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



Conclusion

This is a very good universal LiIon charger, it can handle most types and sizes of LiIon batteries.
The usb output is also good, but I am missing an overload protection.



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

Thanks HKJ. Looks like a very good candidate as replacement for my SP2… if only they make another 2A current charge with same feature as this one.

Nice review, thank you.

So many chargers to choose from these days

Thanks HKJ.

I have a few 15270 cells — “800 mAh” — these are 3.0v “RCR2” size
I’ve been assuming they would be Ok at the low power charging setting.
But they’re ancient Trustfire brand, from long ago.
Any good advice on charging these with the WP2H?

Use the 3.2 volt setting and low current.

Five months in, and the third blue LED on the WP2H has quit lighting up.
(It should light up to show selecting the 3.7v setting first; and then it should light up when the pushbutton is clicked to change to 1A charging)

No light at all from that LED. I wonder if this is just a failed LED, or if it indicates something else wrong with the charger.

Just curious and reporting in case it’s of interest.

I don’t expect to dig into the innards of this one myself because
— It’s within the Xtar 6-month “free repair, return to seller for service” warranty and
— fortunately I bought it from MtnElectronics, in the US as I am, so US postage to return it is reasonable.

And I exchanged that for a new one, which worked a few times, now the second blue LED is intermittent.
It’s intermittent so far — it doesn’t light up only the first time I plug in the AC power
(not during the initial self test nor when the selector slide switch changes nor when the amperage button is clicked.

If I leave the charger on the AC connection after a little while that LED starts working and works consistently.

Another oddity is that the 4th blue LED — the one meant to indicate the USB battery output is working — doesn’t do that.
It does light up during self test, and it does light up very faintly intermittently at other times. Like it lights up faintly along with the first or third blue LEDs when 0.5A or 1.5A are selected. But it doesn’t light up faintly when the 2nd blue LED is (or should be) illuminated to show 1.0A.

Really weird. Still intermittent after a couple of days (this after a week or two of behaving properly).
I’ll keep using it to see if I get a hard failure, I guess.

I wonder if there’s any chance it’s more than the LEDs that are weird, could those indicate something wrong with the actual power sent to the battery when charging?

Following up, after a year I continued to use the charger despite the odd behavior of the blue LEDs
Seems the only flakiness is with the LEDs lighting up.
The charging behavior has always matched the switch settings and the results have been as expected.

I’m wondering if anyone else has seen problems like that.

I’m about to buy another LiFePO4 charger for a relative and wondering whether to get another WP2H, a VP2, or I don’t know what else.
(from Xtardirect, both VP2 and WP2H cost the same $29 at present)

Any side-by-side comparison for chargers that will charge LiFePO4 cells? Pointer welcome.

(Xtar says

So given they both cost the same at present, I guess I”m going with the VP2 next time.
So many choices, so little time ….

Hey Hank, Richard is selling the WP2H for $13 here if you’re interstested.

Wow. That’s a stocking-stuffer holiday shopping price.