XTAR "Over 4 Slim" Charger

Gauss163

Flashlight Enthusiast
Joined
Oct 20, 2013
Messages
1,604
Location
USA
It works nicely, but I wonder how good the automatic current selection is going to be in the final version.

Does that mean that you tested a beta version, and it had some problems with auto-current selection? It would be interesting to know more about such.
 

HKJ

Flashaholic
Joined
Mar 26, 2008
Messages
9,715
Location
Copenhagen, Denmark
Does that mean that you tested a beta version, and it had some problems with auto-current selection? It would be interesting to know more about such.

Yes, it means I did a fast test (I am usual short on time) on a beta version, I am not going to say much about the result, except that I like the charger (It is simple to use and has some very good features). Current selection and other more specific comments will have to wait until I have tested the final version.
 

Gauss163

Flashlight Enthusiast
Joined
Oct 20, 2013
Messages
1,604
Location
USA
Yes, it means I did a fast test (I am usual short on time) on a beta version, I am not going to say much about the result, except that I like the charger (It is simple to use and has some very good features). Current selection and other more specific comments will have to wait until I have tested the final version.

It seems auto-current selection heuristics are slowly percolating into consumer level chargers as of late. It would be very useful to do an in-depth analysis of this, since it if is not implemented correctly it could possibly lead to safety problems.
 

rizky_p

Flashlight Enthusiast
Joined
Mar 26, 2006
Messages
1,440
Location
13th Colony
i Received mine, Nice charger look different compared to other black design. This the LCD and the informations on it. Bright LCD with good angle.
Charging 26650 at 4A is hot though as you can see.


VrUGBRD.jpg

aEYCfvt.jpg
 
Last edited:

markr6

Flashaholic
Joined
Jul 16, 2012
Messages
9,258
Pretty cool! I just don't like automatic anything. That's just me. And that design...big 80s totally awesome dude!!!!
 

rizky_p

Flashlight Enthusiast
Joined
Mar 26, 2006
Messages
1,440
Location
13th Colony
i dont know that this charger has automatic current selection. But you can adjust the current manually with CH1/CH2 button and cycles through 3 current selection which is 1A/2A/4.1A.



Pretty cool! I just don't like automatic anything. That's just me. And that design...big 80s totally awesome dude!!!!
 

WalkIntoTheLight

Flashlight Enthusiast
Joined
Jun 18, 2014
Messages
3,967
Location
Canada
I suppose it might be useful if you have to charge 26650's in a hurry. But, for 18650's, it's too high a current. The spec sheets for most cells list the max charge at 1C and recommended charge at 0.5C. I wouldn't trust its automatic selection based on internal resistance (chargers are horrible at measuring IR accurately, anyway).
 

terjee

Enlightened
Joined
Jul 24, 2016
Messages
729
Location
Bergen, Norway
But, for 18650's, it's too high a current.

As a datapoint, VTC5A is listed as up to 6A for charging. Never tested it, but I've never had any issues with 3A.

The high rate is my main reason for considering this charger actually. Being able to quickly top up if I have to.

I'll definitively agree that it falls under advanced usage though, and warrants caution and careful reading of data sheets (not just max rate, but rate against temperature and whatnot).

As for IR measurement in chargers, I'd guess a well designed setup would be more likely to show too high resistance rather than too low, which should result in a lower charge rate. Will be interesting to see what both lab testing and practical testing turns up from different sources.
 

WalkIntoTheLight

Flashlight Enthusiast
Joined
Jun 18, 2014
Messages
3,967
Location
Canada
As a datapoint, VTC5A is listed as up to 6A for charging. Never tested it, but I've never had any issues with 3A.

The high rate is my main reason for considering this charger actually. Being able to quickly top up if I have to.

Are you sure it can quickly top-up? Without looking at the charger's specs, I assume it is a standard CC/CV design. So, you'll only get the 4.1 amp charge during the main phase of the charge. The last 10%-20% of the charge will be CV, so it's not going to be very fast for topping up.

I have a Nitecore SC4 that does 3 amp (per cell) charging, but only until the CV phase kicks in a little past 4.00v. Then, the amps drop dramatically, and it takes about an hour to finish the charge.

But, yes, if you want to top up to about 80% charge, it's fast.
 

Gauss163

Flashlight Enthusiast
Joined
Oct 20, 2013
Messages
1,604
Location
USA
Are you sure it can quickly top-up? Without looking at the charger's specs, I assume it is a standard CC/CV design. So, you'll only get the 4.1 amp charge during the main phase of the charge. The last 10%-20% of the charge will be CV, so it's not going to be very fast for topping up [...]

Right, but it is long known that it is safe to charge even faster at lower SOC (e.g. see the links I gave here for Philips and Tesla multistage fast charging algorithms), so one can exploit this to counterbalance the slowness of the final CV stage. But these ideas have yet to percolate down into consumer level chargers. They're already heavily employed in EV use (e.g. Tesla) and they should soon appear in cell phones now that higher power is available (QC, USB-3/PD, etc).
 
Last edited:

terjee

Enlightened
Joined
Jul 24, 2016
Messages
729
Location
Bergen, Norway
Are you sure it can quickly top-up?

Granted, top-up might have been a poor choice of words.

Just thinking about use cases such as airports, cafes and hotel rooms, where you might want to dump a lot of energy into otherwise somewhat drained cells, and have maybe half an hour or so to do it.
 

StandardBattery

Flashlight Enthusiast
Joined
Sep 2, 2007
Messages
2,959
Location
MA
i Received mine, Nice charger look different compared to other black design. This the LCD and the informations on it. Bright LCD with good angle.
Charging 26650 at 4A is hot though as you can see.

....
Nice! where did you get it? Did you order earlier through that buy on the other forum?

Some of the latest apple devices with the right charger will use a variable CC charge rate depending on the cell voltage and it seems to work quite well. allows one to bring the device upto 50% quite fast. Most people don't have the right chargers for this though; I do find it very convenient on the iPad Pro.
 

olemil

Newly Enlightened
Joined
Nov 30, 2013
Messages
164
Location
Michigan
I really like the looks of this! Finally a charger that can sit on the desk and not have the usual black chunk of plastic look. I like the looks of the black and blue model, pretty sharp. Don't really need another charger, only thing I would be charging at that high of current would be my 26650's. Can't wait to see the pricing and availability in the US. Merry Christmas everyone!!!
 

nfetterly

Flashlight Enthusiast
Joined
Oct 17, 2008
Messages
3,764
Location
Cincinnati area, but lots of travel
Dual 2.4A USB chargers is a nice addition as well for someone who travels alot (me).

edit - found review on BLF via google, not so great for travel as you get a big "brick" as well. Gives a nice photo of the temperature "probe" that measures the temp of the outside of the battery.

Merry Christmas!
 
Last edited:
Top