Thank you for the review!
Does the product twist if you try to twist it?
Looks so small and cheap thin plastic china :)
Yes, but I have to twist rather hard, for the size I will call it strong.
Thank you for your honest evaluation. I will put it on my short list!! 
Thanks for the review! This is a good feature but 500mA is really both too high and too low for my needs from a small USB charger. ML-102 v5/6 is better buy I think; with some modification it can accept protected cells.
There will always be individual preferences. I believe Xtar has selected a good current for a light weight charger. 500mA is the maximum current you want for 16340 cells and you can also charger 26650 if you have a some patience.
The ML102 has a couple of other tricks (usb output), but it cannot handle this wide span of battery sizes. It is very good value for money.
For a really universal small charger, you need the SP1, but that is another price and not nearly as light weight.
I have one of these, or should say “had” one of these
MAJOR flaw in the design…they use the VERY flimsy surface mount micro USB connector and not the substantially stronger thru hole usb connector, a good tug on the cord (if it slips off your desk or whatever with a decently hefty 18650 in it) there is a very good chance it will literally tear that tiny micro USB loose from the soldering…how do I know this…it happened to me 3x times and I resoldered it, and it is NOT easy reasoldering those teeny tiny pins
Only way to open it is destructive by literally cracking open the bottom to get to the board, then supergluing/epoxying it back on (it uses rails on the bottom cover for support of the slider rails on top, without the bottom cover securely held in place the rail can flex, and the slider spring slips/falls off the little support stud [no more retractable slider])
I even tried epoxying over the connector (after I resoldered the little feet back to the board, but it came off again…got fed up and stripped the board, soldered on a pigtail and soldered down to one of the HKJ reviewed TP4056 USB charging modules…works great but would much rather have the stronger thru hole USB micro connector
With that said…it is an INCREDIBLE charger, not many offer the sliding different size charge platform, you can’t beat it for $5.95~
P.S. It uses the TP4057 IC chip
http://www.tpmicro.com/goods.php?id=48
My writeup here
However, must say, awesome writeup as usual HKJ…love to see the CC/CV curve in the graphs 
I love the size, and that it uses the same usb cable as my Kindle and tablet. Very convenient. Not crazy about the weak usb port. I hope they fix that usb port. It'd be really awesome if that added nimh charging capability.
I have never had this kind of problems, but I am usual careful when plugging and unplugging small connectors.
Micro usb is the usb connector that has the longest life (most mating cycles).
That would give heat problems and in my opinion a single channel is to little for AA(A) batteries.
Why would it cause heat problems?
Single channel would be perfect for me. Zebralight H52. It'd be nice to carry both battery types and have one charger work for both.
It’s not the connector that is the problem…it is the physical mounting of the connector on the PCB inside the charger that is the problem
This is the type of USB connector on the Miller Version 6, it’s a surface mount but has the thru hole feet, as you see they hang thru the board and are soldered in the board, MUCH stronger than the below
This is a SMD surface mount, notice the feet go out away (like wings rather than claws), they are soldered to pads on the board, as we know solder on chromed metal doesn’t stick all that well…thus a good tug lifts the feet, pulling the teeny pins usually breaking them…which means kaput charger
Externally they look the exact same…until you see the board, you don’t know if you have the stronger USB Micro connection or not…some USB micro connectors only have one foot to solder down, most of the USB Mini have two
Problems may be to strong a word, but instead of having 0.7 watt of heat it will have 1.4 watt of heat to get rid of, due to the lower voltage on the battery.
I was thinking of getting a few as gift chargers, but my only concern is if this charger has reverse battery protection?
Thanks for the review.
Edit, just found the data sheet, it looks like it does. I think I answered my own question.
Yup…put the battery in backwards the charging LED goes out…ask me how I know 
The Xtar MC1 seems like an excellent choice for a car, cigarette lighter, usb adapter, since it sounds like it handles fluctuations.
Am I correct, and if so, running or not running the car should make no difference?
They charge great…500mA but charge VERY good…and are teeny tiny
Being without a microcontroller it handles fluctuations easy, i.e. solar panel or car ought to work well.
But it can probably not handle spikes from the electric supply, the 12V -> 5V adapter must handle that.
The car charger is an authentic AT&T Micro-USB Car Charger with USB Port 2Amp, so I guess that it would handle the spikes?
I just realized that my small Rosewill inverter has a USB 1Amp port, so it would probably handle spikes better than the above. Rosewill 150W Can Sized Silent Car Inverter with 1Amp USB Port RCP-E150C - Newegg.com
well it only is sooo slow, takes 10h to get a 2600 mah protected eagletac battery from 3.6 to 4.2
(yes indeed 10+ hours!)
Are you sure? Should be around 6 hrs.
can it accept a 5v 2Amps travel adapter used for tablet phone or it only accept a 5v 0.5Amps adapter only?