Friday, December 12, 2014

Review: XTAR VC2 USB Lithium-Ion Battery Charger

The USB form factor is fantastic for mobile and portable power. High capacity battery packs have changed the way I travel with my devices, so I'm always interested to see genuinely-useful devices I can power with those power banks other than just the typical phones and tablets. USB devices I would put in the useful category include LED lanterns, walkie-talkies, and now lithium-ion chargers. This VC2 Charger one was provided by the manufacturer, XTAR. They make good flashlights, but lately they are almost better known for their chargers. They share the field with other established flashlight makers like Nitecore.

XTAR VC2 Lithium-Ion USB Charger - Product View


Product Description


This is a USB powered lithium-ion charger featuring two separate charging channels and sliding, spring-loading connectors to charge a wide variety of different batteries. The list of cells it can charge is a pretty good list. It has some other interesting features like sensing and reactivating low voltage or 0V cells, due to over-discharge or tripping the protection circuit included on some cells. It has a back-lit LCD display where the indicators look like automotive instrumentation.


XTAR VC2 Lithium-Ion USB Charger - Product View 2

XTAR VC2 Lithium-Ion USB Charger - Product View 3

XTAR VC2 Lithium-Ion USB Charger - Product View 4


Official Specs (From their official document)







What's Included?


The box comes with the charger, a micro USB cable and a felt, draw-string pouch. XTAR wanted me to point out that an AC wall charger is NOT included. And my wife wanted me to point out that she thought an AC-to-USB adapter should be included. It doesn't really matter to me. I have a whole bunch of those. How many does the average person need?

XTAR VC2 Lithium-Ion USB Charger - Box 1
XTAR VC2 Lithium-Ion USB Charger - Box 2

XTAR VC2 Lithium-Ion USB Charger - Box 3


Initial Impressions


The charger is sleek and high tech looking. Admiring its construction, it dawned on me to try the spring loaded contacts and get the disappointment over with, like with my Nitecore, Opus and UltraFire chargers, which I hate the sliding contacts on. But they slide smoothly, even when pressed from a weird angle.

Grabbing the AW 16340 cell out of the flashlight on my nightstand, popping it into the charger and plugging the charger into one of my power packs was painless, and the charger fired right up and started charging my cell.

I also noticed the little rubber feet on the bottom of the unit. They are not the typical mis-aligned, half-glued ones on most of my other chargers.

Build Quality


My review sample looks to be well built, probably the best build quality of all my chargers. I will leave it to more technical reviewers to judge the nuances of the internal charging circuitry. Just as important to me is the high impact construction that doesn't look like it will break into 100 pieces if I drop it.

Fit and Finish



Overall, good. There's a tiny but deep scratch on the shiny plastic display. Which normally wouldn't be a big deal, but it's ironically positioned almost perfectly over the charge current display, making it look like it is giving two different readings at the same time with the way the back light hits the scratch. That's not a big deal for me, but someone else might find it annoying.

Other than that, the rest of it is pretty much perfect, and way better than my other chargers. I love my Nitecore I4, and it's my preferred charger most of the time, but the feel of putting a battery in is awful compared to this charger.

I think the camera does a decent job below of showing the above-average fit and finish.

XTAR VC2 Lithium-Ion USB Charger - Finish 1

XTAR VC2 Lithium-Ion USB Charger - Finish 2

User Operation


This charger is pretty much idiot-proof. You put 1 or 2 cells in it, and plug it into some USB power source, which means literally anything such as a USB AC wall outlet, auto 12V USB adapter, power pack and even solar chargers like my 13 watt Levin, which has a USB output.

When the unit powers on, it does a little self-test and initialization, briefly flashing all the LCD elements. Then it starts measuring the voltage of your cells(s) and tracking the capacity as they charge.

XTAR VC2 Lithium-Ion USB Charger - Startup

Charge Current


The 500 mA charge current (per channel) is sufficient given that it's USB powered and how compact it is. And that means the maximum current this charger will draw from its USB host will be one amp.

XTAR VC2 Lithium-Ion USB Charger - Capacity Reading

Current Reading


Unlike the voltage indicators, the charger chooses a current between 150 mA and 500 mA. In practice I've never seen it read other than 500. I can't think of a case where I wouldn't want it to be 500, so that's fine by me. I'd be curious to know the actual conditions where the charger would choose a low value like 150 mA.

Voltage Reading


The VC2 has an automotive dashboard style interface, making it easy to read the current voltage of each channel at a glance. It's a back-lit LCD and it's fairly crisp looking. The indicators show you the voltage reading in real time, stopping at 4.2V.

Capacity Reading


The VC2 will start measuring your capacity from the moment it powers on or you put a cell in it. Which means that to get a true reading of a cell's capacity, you'll want to put a discharged cell in it to start with. Some chargers like my Opus have a charge-discharge-charge feature to put a cell through its paces and give you an accurate reading of a cell's capacity, the way the VC2 does it is still fine.


Battery Types


This charger takes lots of different types of batteries, and for my test I personally tested it with 10440, 14500, 16340 (and IMR) and 18650 cells. Keep in mind that a high capacity 18650 or 26650 could take all day to charge at half an amp.


0V Activation 


XTAR wanted me to point out their 0V activation function, which lets you revive a 0V or low voltage cell, as well as reactivate a protected cell with the protection circuit tripped. Here is a link to their explanation of the feature.

A few of my cells were treated unkindly in order to test this feature. Unprotected cells should never ever be taken under maybe 2 volts. It's definitely not good to take them down to 0, and some people will even stop using them if that happens. Me, I just go by the numbers. If a cell acts like a good cell, then it gets treated like a good cell.

Below you can see that the VC2 is correctly sensing the 0V IMR battery that had to take one for the team. Also notice the scratch on the display makes the current reading look funny.

XTAR VC2 USB Lithium-Ion Battery Charger: 0V Activation


Dead Cells / Wrong Cells


If you put a cell that the charger thinks can't be revived, or you put in a cell with a chemistry the charger doesn't support, it will read "null" for that channel.

Full Charge Indicator


The charger will periodically flash the entire display when one or both channels are finished charging, meaning they have reached the 4.2V cutoff voltage.

Usability


This is a very nice and convenient charger to use for smaller capacity batteries like the 10440, 16340 and 14500 cells used in small, high-powered LED flashlights. For example, I keep an eFest 550 mAh IMR cell in my Sunwayman V11R flashlight on my nightstand. At 500 mA, it's only about an hour to charge it. Now picture a 5,000 mAh 26650 cell: the basic math says it'll take 10 hours.

Sliding different batteries into the unit is not a painful process like my other chargers. The springs move smoothly.

Conclusions


I think the the VC2 is a fine mobile charger, and a fine addition to my mobile technology arsenal. At only half an amp charge rate, it's not going to replace my larger, plug-in chargers like the Opus for everyday use, but now that I have this charger, I couldn't picture not taking it on a long road trip.

Gallery


XTAR VC2 Lithium-Ion USB Charger - In Box 1XTAR VC2 Lithium-Ion USB Charger - In Box 2


XTAR VC2 Lithium-Ion USB Charger - In Box 3XTAR VC2 Lithium-Ion USB Charger - In Box 4

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