What USB adapter are you using? My Xtar VC4 needs a good 2A adapter to work. I tried it with a knockoff charger that was supposed to be 8A four port with four 2A jacks. It wasn't strong enough to do the job in spite of its claimed amp rating and weird things started happening. I bought an Xtar brand 2A charger for $9.99 and life has been good.
I mostly only use authentic UL listed adapters! I think it's US's quality test approval, but if not, from what I remember when I did this research a while ago is that UL is the most trusted.
I trust UL more than EU's CE mark and the FCC mark.
FCC is US also but the reason I trust UL is a lot of the $0.79 adapters on ebay say FCC and/or CE but not UL. I think some of those are just counterfeit, there's not much stopping a Chinese manufacturer from forging CE and FCC like they did with faked apple adapters. But it's seldom you'll find something cheap from china that says UL, so I usually go with the UL ones.
I have a few authentic (I'm assuming) UL ones that came with new cell phones I use.
True, the VC2 plus also requires 2.1A to charge at 1 full amp, otherwise it's .5A charging. 2A won't do it.
I got fed up with trying to find UL listed adapters (just the separate adapter) without paying like $10 for them when I bought a few more adapters on ebay. I figured I was just being paranoid and got the $1 ones that say FCC and CE, same with the car adapters I got. The car ones never gave a problem. But the "2.1A" 79cent ones were not giving a full 2.1A, it was probably doing 2A (I would see a lot that looked similar and some would claim 2.1A but others claimed 2A).
The Xtar will not charge 2 (or maybe even just 1) of the 2 bays at a full 1A unless it's 2.1A. I ended up opening cases for the adapters and getting them free.
It's safer though to charge at .5A (2.1A adapter) than a full 1A - it's like a slower trickle charge, so I prefer it anyway but I might still have the $1 "FCC CE" adapter which I ended up getting for free hooked up in the garage to .5A charge dual protected 18650s for an LED headlamp but that one never gave a problem other than not providing 2.1A to charge at 1A.
well actually after opening the case and trying to explain this in someone who speak Chinese, I did get those free adapters to charge at a full 1A.
Just like this person said in an amazon review. He still gave it 5 stars though:
"Another thing I noticed was that in the first couple hours of charging, it would only charge at 0.5 amps. If I tried to switch into 1 amp mode it would default back to 0.5 automatically. Then, as if by MAGIC, I finally got it to stay in 1.0 amp mode which, obviously, reduced my displayed charging time in half. Maybe it was because of the new batteries, I don't know."
It could just be the charger too, but I guess I haven't use it much to know for sure.
Everyone's concerned about charging mods VIA usb, and I don't recommend that either, but I have had ZERO problems ever USB charging triple 18650s in a DNA mod. The DNA chip charges so balanced I might prefer it over these "safe" nitecore and Xtar external chargers. And I don't have to pop cells in and out and possibly damage the wraps, and of course it's just so easy to just plug it in and charge.
My first external was a nitecore (for the headlamp protected 18650s), and one month past the 1 year warranty after only using it about 25 times, bay 2 would not charge so I changed to Xtar.
I'll use this Xtar some more with other adapters and if it's still doing this I'll warranty it. There's still at least one other brand besides nitecore and Xtar that are said to be among the best chargers so I'll try that next maybe. I got the VC2 plusses for only like $9.50 shipped on ebay from china.
