Charger Xtar WP2h

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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.


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

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

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

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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.

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

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

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



Measurements

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

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

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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.

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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.

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The second channels looks like the first.

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

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

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

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

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

Temp1408

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.

Temp1409

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

Startup

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

Charge

Changing current will slowly ramp up to the selected current.



4.35 volt charging (Switch position 3.8V)

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


LiFePO4 charging (Switch position 3.2V)

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LiFePO4 is also charged correctly.



USB output
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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.

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

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

5ohm

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

10ohm

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