Review of / Measurement on Charger Xtar VP1

HKJ

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[SIZE=+3]Charger Xtar VP1[/SIZE]

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Xtar has made some good LiIon chargers, this is their latest model, introduced in January 2013. It has two channels each with a voltmeter and 3 current settings.

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It comes in a box made of plastic with a view to the charger and specifications on the back.

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In the box is the charger, a power supply, a car adapter, a instruction sheet and a warranty card.
The power supply I got was with US plug, but universal voltage (100-240VAC 50/60Hz).

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The charger has a DC connector for power input.

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The slots has raised battery connections, i.e. flat top batteries can be used. The slider works very smooth, with 16340 batteries the pressure is a bit low, but enough to get a connection. The maximum length is enough to take my longest battery, i.e. more than 70 mm. There is also a clear marking of polarity.
I will say that these slots work very well for the supported battery sizes.

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On the top of the charger is a switch to select charge current, it can select between 0.25A, 0.50A and 1.00A, the current will be the same in both slots.

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The display is the a new feature for Xtar and with the exception of hobby chargers, I do not know of other chargers with this resolution.
Everything is, of course, shown on the display and not with leds: The voltage of each battery, the selected charge current and the charge state.
I have found two minor cosmetic details with the display. The first one is the background lightning, if the display is looked at from most angles it has a bright white border. The second detail is the "charge finished" signaling, there is no indicator to show when the charge is finished, you have to look at the fill state in the battery symbol, when all five bars are steady, the battery is finished. I would have preferred a more clear indication.
The voltmeter has a good precision, when charging it will show slightly above the battery voltage, as expected. Sadly it will not really work above 4.20 volt (It will show one value and then stop updating).

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Xtar has recently started adding a product verification code to their equipment. This code can be verified on their website.
But either my charger is a fake or there is some problem with the verifications system. My label has 3 groups of 6 digits, on the website you have to use 4 groups of 5 digits?

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The charger can handle 70 mm long batteries, inclusive flat top cells.



[SIZE=+2]Measurements[/SIZE]


  • Below 2.0 volt The charge current is between 2 and 3 mA.
  • Between 1.5 volt and 2.0 volt the battery symbol will flash.
  • Between 2.0 and 2.9 volt the charger current is about 42mA/42mA/72mA in the 3 current ranges.
  • Above 2.9 volt the regular CC/CV is used, se curve below.
  • Without power if will discharge the battery with about 0.5mA.
  • With power it will charge with about 0.5 mA when the battery is full.
  • Build in voltmeter is +0.015 volt at 0.25A
  • Build in voltmeter is +0.025 volt at 1.00A
  • The voltmeter can show voltages above 4.20 volt, but lock up and will not update anymore, before voltage is below 4.20 volt again.
  • The voltmeter will only be enabled with battery voltages above 1.5 volt.
  • Charge will restart if battery voltage drops to 3.9 volt.
  • The charger will restart when a battery is inserted or power is cycled.
  • Because each channel is independent, the different voltages varies between the channels with a small amount.



ChargerXtar%20VP1%200.25A%20(PS18650-34).png


The first charge curve is at the lowest charge current, it is a perfect CC/CV charge with termination at about 45mA. This is good, but a slightly lower termination current would have been better.

ChargerXtar%20VP1%200.5A%20(PS18650-34).png


Increasing the current to 0.5A, does also give a perfect CC/CV curve. The termination current is again about 45 mA at this current it is very good.

ChargerXtar%20VP1%201A%20(PS18650-34).png


Same at 1A, notice that the termination current is increased to about 75mA, again a very good performance.

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The second channel looks just as good as the first channel.

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Running both channels at the same time, does not change the curve, i.e. the channels are independent.

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A 2600mAh battery will, of course, charge faster.

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A smaller battery, works just as well.

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My old worn down 16340 IMR cell is charged just as nice as any other battery.

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One more try with the old 16340 cell, this time at 1A (Some other brand told me that this was not allowed with their charger).
With the VP1 there is no problem, it is just charged with a good CC/CV.

That it is a old worn out cell can also be seen on the voltmeter, the voltage will drop significantly within a couple of minutes, when the charge current is stopped.

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When the charger is powered on, it will use some time to initialize, then the current will be slowly ramped up to the full charge current.
It is possible to change the charge current before it starts charging, but because it always power up at 0.25A it is not required.

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It is also possible to change the charge current during charge.

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Here is a voltmeter test, while charging at 1A. There will be some voltage drop in the connection to the battery, this also means that the error will be less at lower charge currents.


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



[SIZE=+2]Conclusion[/SIZE]

This charger does a perfect CC/CV, making it a fast charger or at least as fast as possible without cheating. With currents from 0.25 to 1A it covers many of the common batteries sizes, only exception is 26650 batteries and with a piece of tinfoil it is possible to charge one in the charger. I like the voltmeter, this makes it easy to see the charge state and also possible to spot a worn down battery.
I could have wished for a better "finished" indication and I would also like a larger range on the voltmeter, say from 0.00 volt to 4.35 volt.

I will rate this charger as very good.

Is this charger better than SP2? The charging is about the same, the advantages are from the voltmeter and from the lower charge current. The voltmeter is a nice feature for me, I am too lazy to check with a voltmeter each time I charge, now I can just look at the display. The 0.25A current makes it possible to charge 10440 cells and is slightly better for 16340 and some 14500 batteries. For me this makes the VP1 slightly better than SP2 and it will replace my SP2 as my most used charger.

For people that wants 4.20 volt on their batteries, this is not the charger, this charger uses the correct algorithm and the battery voltage will drop slightly below 4.20 volt when the charge is stopped.



[SIZE=+3]Notes[/SIZE]

I did all the tests at 110 VAC, because I bought the charger from US and got a US power supply.

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

cyclesport

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Re: Review of / Measurement on Charger Xtar VP

Thanks for yet another great detailed review HKJ! I've been waiting for this unit to become available for awhile (although I had wished for a four bay)and plan to buy one in the near future. Somewhat surprised there hasn't been more interest it it at this point.
 

RI Chevy

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Re: Review of / Measurement on Charger Xtar VP

Thank you for doing this for us! :thumbsup:
 

donn_

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Re: Review of / Measurement on Charger Xtar VP

Great review...thanks.

I got my Xtar chargers yesterday, including this one, and really like them.

I charged two pairs of cells on the VP1; 18650s (@1A) and 18490s(@0.5A). On each pair, the battery indicator kept flashing the last bar after the voltmeter reached 4.20. I waited 10 minutes to see if they would go all steady, but they did not. My Fluke read the 18650s at 4.09V and the 18490s at 4.18V.

I took an old over-discharged 26650 and tried it in the SP2. Its voltage was 1.04V before I started it on the 2A setting. It sat for 20 minutes before the LED went to red. It did, however, charge the cell normally after that waiting period.

I haven't charged a cell on the WP2 II yet, but I used a charged 18650 to recharge my cell phone via the USB outlet. Very handy feature.

All in all, I'm impressed with the Xtar chargers. I particularly like the faster charging rates. I also like the rubber feet. They keep the chargers in place better than most.

I tried to register them on the Xtar website, as suggested on the warranty cards, but could not find the feature on the site.
 

HKJ

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Re: Review of / Measurement on Charger Xtar VP

I charged two pairs of cells on the VP1; 18650s (@1A) and 18490s(@0.5A). On each pair, the battery indicator kept flashing the last bar after the voltmeter reached 4.20. I waited 10 minutes to see if they would go all steady, but they did not. My Fluke read the 18650s at 4.09V and the 18490s at 4.18V.

A real CC/CV charger is not finished when it reached 4.20 volt, as you can see on my curve, the charger may need an hour more.
 

donn_

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Re: Review of / Measurement on Charger Xtar VP

A real CC/CV charger is not finished when it reached 4.20 volt, as you can see on my curve, the charger may need an hour more.

Sure enough. I put the 18490s back on the charger, and after about 20 minutes the indicators went steady. They clocked 4.195 on the DMM.

Can you describe the use of foil in charging 26xxx cells? Are you using it so the contact will reach the positive end of the cell?
 

HKJ

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Re: Review of / Measurement on Charger Xtar VP

Can you describe the use of foil in charging 26xxx cells? Are you using it so the contact will reach the positive end of the cell?

It is not the positive contact, but the negative (At least when the cell has a large top):

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It will depend on the wrapping, some of my 26650 did not need the tinfoil.
 

__philippe

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Re: Review of / Measurement on Charger Xtar VP

Another HKJ's superbly illustrated measurement/test/review, thanks.

Hints to manufacturer for the next XTAR VP1 mark II iteration, which is sure to follow in a few months (weeks?)

- add one latching green LED per channel to provide positive charge termination signal
- allow actual voltage display over the 4.20 V present limit
- fix cosmetic blemish around display bezel
- introduce a 4-bay version ?
- lower current price..?

Cheers,

__philippe
 

vali

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Re: Review of / Measurement on Charger Xtar VP

For people that wants 4.20 volt on their batteries, this is not the charger, this charger uses the correct algorithm and the battery voltage will drop slightly below 4.20 volt when the charge is stopped.

On the other hand, charging like this the batteries will last longer. I remember one thread in the forum that stated something like charging up to 4.15 or so will double the battery cycles. Tried to find that, but no luck :( (maybe it is my memory playing tricks on me)
 

Mr Happy

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Re: Review of / Measurement on Charger Xtar VP

It is not the positive contact, but the negative (At least when the cell has a large top):

DSC_1714.jpg


It will depend on the wrapping, some of my 26650 did not need the tinfoil.

Just a note for anyone thinking about this. I my experiments with aluminum foil I have found the electrical contact to be slightly high resistance and unreliable due to the oxide layer coating the foil. For better results try to use tinned copper foil or something similar with a more conductive surface.
 

HKJ

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Re: Review of / Measurement on Charger Xtar VP

Just a note for anyone thinking about this. I my experiments with aluminum foil I have found the electrical contact to be slightly high resistance and unreliable due to the oxide layer coating the foil. For better results try to use tinned copper foil or something similar with a more conductive surface.

Probably a good idea, but be careful, I have cut my fingers on real copper foil a lot of times.
 

psychbeat

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Review of / Measurement on Charger Xtar VP

Can u bridge the channels to charge @2 amps?
I assume this is probably a bad idea ;)
 

neutralwhite

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Re: Review of / Measurement on Charger Xtar VP

hi dear HKJ, excuse me for any confusion, - in your review you stated " For people that wants 4.20 volt on their batteries, this is not the charger, this charger uses the correct algorithm and the battery voltage will drop slightly below 4.20 volt when the charge is stopped. "



so would this be fine enough to charge an AW 3100mAh 18650 battery?.
its a 3.7v battery right which charges up to 4.2v correct?.
what will the charger read when fully charged ?. 3.7? / 4.20?

thanks.
 

HKJ

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Re: Review of / Measurement on Charger Xtar VP

hi dear HKJ, excuse me for any confusion, - in your review you stated " For people that wants 4.20 volt on their batteries, this is not the charger, this charger uses the correct algorithm and the battery voltage will drop slightly below 4.20 volt when the charge is stopped. "



so would this be fine enough to charge an AW 3100mAh 18650 battery?.
its a 3.7v battery right which charges up to 4.2v correct?.
what will the charger read when fully charged ?. 3.7? / 4.20?

thanks.

Yes, it will be perfectly fine to charge any 3.6 volt or 3.7 volt LiIon battery.

During charge it will go up to 4.20 volt, but when charge is finished it will probably drop to 4.19 or 4.18 volt (Depending on age and size of battery).

Me remark above was because some people believes that a fully charged battery has to read 4.20 volt. That is not correct, the charger has to use 4.20 volt and that is not the same.
 

neutralwhite

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Re: Review of / Measurement on Charger Xtar VP

many thanks, about to order this charger, thanks to you!. lol.
the Fenix ARE C1 is gone, again thanks to you.

your a credit to cpf !. thank you for your time, and this clear cut review.

goodnight.
 

Husker

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Re: Review of / Measurement on Charger Xtar VP

OK...So where do I order this from? I will Google but if you have a recommendation, lay it on me please.
Great review, I was waiting for your review before pulling the trigger on my 1st charger-->:goodjob:
 

ggroyal1117

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Re: Review of / Measurement on Charger Xtar VP

I have been using my VP1 for about one month. It works great on all of my 18650 batteries.
Thanks for the excellent review.
 
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