Review: XTAR VC2 USB Charger
More power bricks. That’s usually what charging my lithium-ion batteries means on the road. All these power bricks just to give me 5V and 12V packaged in different, incompatible ways. This is why I prefer to carry as many of my devices in USB format as possible and practical. This is why I’m a big fan of USB power packs, chargers and lanterns. And this is why I am always more than thrilled to receive these kinds of products for review. This sample was provided by XTAR, who seem to be very passionate about their work, judging by the number of emails with them. The full review can be found here on my blog, and for this version I’m going to mainly be pointing out the prominent features and limitations.
USB Powered
The VC2 is powered entirely by its micro USB port. It comes with a micro USB cable and a pouch, and that’s it. It does not come with a USB AC wall charger—just like the last Android tablet I purchased. Which means this charger can be powered from power packs and all maner of wall and solar chargers.
Features
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USB Powered
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0V Cell "Activation"
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Automotive Style LCD Instrument Panel
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2 Separate Charging Channels
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Basic Capacity Measurement
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Real time "speedometer" voltage display-one for each channel
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Real time "speedometer" current display-one for both channels
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Flashes entire display when one or both cells are full
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Auto-senses bad cells and cells of the wrong chemistry
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Three stages of charging (TC-CC-CV)
Official Specs
Initial Impressions
I like how smoothly the spring-loaded contacts slide back and forth, and the overall impression of quality and finish. The Nitecore I4 is probably my most-used charger, but I silently curse it each time I have to put a battery in because those sliding contacts are just atrocious. I have a couple other similar chargers and they aren’t much better in this department. So, it’s refreshing to see a company, you know, actually care about the end user experience. The only that made me frown unboxing it was the tiny but deep nick in the display portion, right over the charge current indicator.
Usability
To try to simulate conditions on a road trip, I only used other USB power banks to power the VC2. The included cable wasn’t tested because under real world conditions, I would throw it in a drawer and use the cables I already use. The charger is idiot-proof; you plug it into a power source and it powers on just like you’d expect, and gets right to work charging any cells that are in it when the unit is powered on.
The charger performed well for my usability tests, aside from only having a 500 mA charging current. For my mobile office, this charger is more likely to be charging a 10440 or 14500 than a larger cell. For larger cells, I guess the compact size and lack of AC power brick is a fair trade for having to wait 7 hours for my Panasonic 18650 cells to charge.
"0V Activation"
XTAR wanted me to point out this feature, and I did my best to test it not being an electronics engineer. A few of my eFest, AW and Nitecore cells took one for the team, and the charger seems to have no problem bringing them back to life. How good will they continue to be after being abused like that? I guess that I’ll find out. They claim that if a cell cannot be revived, or if you put a cell in with an unsupported chemistry, like NiMH, then the charger will read "null" for that channel.
Also notice below that the scratch on the display almost makes it look like two different readings on the charge indicator because of the way the back light reflects off the scratch.
Current Indicator
There’s a single, real-time charge current indicator for both channels, which I’ve only ever seen point to .5A. I was unable to get a photo of it, but once I measured the current at .03A on my USB meter and it was still reading .5A on the display. So I’m not sure how useful this display is, or if you would ever genuinely want it to charge at less than .5A.
Voltage Indicator
There is a voltage incator for each channel, giving you a real-time voltage reading. Like the current indicator, it has a few fixed measurement points arranged like an automotive speedometer. It seems to be accurate and I really like the way it’s laid out. It’s crisp and easy to read at a glance. It would be nice if the bottom display would cycle through the actual voltage reading as well, but this style of voltage guage is plenty sufficient to see the approximate voltage level at a glance.
Capacity Indicator
The VC2 will start measuring the capacity as soon as it starts charging a cell, which means you will want to completely discharge the cell yourself to get the most accurate measurement. Also keep in mind that it’s usually measuring based on a 500 mA charge rate, which may or may not be useful to your particular usage scenarios, so it’s best to just consider this a rough idea of your capacities and not a concrete, scientific measurement. What it should be good at is showing you cells that are probably not worth keeping, as well as showing you how your cells are holding up over time. This capcity indicator can also show other status messages, such as "Full" or "Null" when appropriate. Otherwise it will continue to blink and update the capacity. I wish it wouldn’t blink. It’s distracting, not to mention a real pain to photograph.
Conclusions
The VC2 is a well built charger with a well balanced set of features for what it is: a mobile charger. I don’t really have much to nit pick about it other than a few minor grievances. It would be nice to have an option to at least run a single channel at one amp. It is acceptable the way it is as a mobile charger, but I would use it more around the house even with a slightly higher charge rate. It would also be nice to have a full-fledged charge test with a charge-discharge-charge cycle.
This unit won’t replace the larger chargers I have plugged into the wall, or the Miller charger that’s in my emergency bag. But there was a third bag hungry for a charger exactly like this because none were light or compact enough: the mobile office bag. This bag places a premium on computing space. It has a laptop, 10 inch tablet, 7 inch tablet, point-and-shoot camera with all manner of input devices, gadgets and office supplies—all in one SwissGear backpack. Space is at an absolute premium and it seems like every business trip I regret not packing a clunky lithium-ion charger along for the trip like I do for camping and the outdoors. So, I think XTAR might have hit some sweet spot in the mobile charger market.
Gallery
