Review: XTAR Over 4 Slim 4A Fast Charger

XTAR Over 4 Slim Fast Charger

The XTAR Over 4 Slim was provided free by Xtar for my honest and unbiased review no other payments are received other then the charger provided.


I have several XTAR Chargers namely ANT MC1 Plus and MC1 all are small traveler friendly chargers with small form factor and also small charging current, what i like about the MC1 is that it is powered by your phone charger but it’s charging current is not something to bring home about.
I have been eyeing a more powerful charger that can charge bigger battery “properly” such as the 26650 most cheap charger can only charge at 1 amps or 2 amps for the more expensive one so when XTAR contacted me if i want to test their new charger with 4.1A charging per slot i was excited to say the least. I have several big boy charger that can charge at 1000w or more but that is what we call a hobby charger, i have been using my hobby charger to charge my 18650 at a higher current if the need arises but such charger is an overkill for this kind of purposes. My smaller ISDT with 8A charging ability can happily charge 4x18650 at 2A each and that is what i have been having so i know that my 18650 Samsung is HOT when charged at 4A.
so now on to the XTAR Over 4 Slim.

High 4.1A current charging.
UI is really simple with only 2 buttons for adjusting current.
Charging current can be changed anytime, choices are 4.1A, 2A, 1A
No changing or scrolling information on the LCD, only the Internal Resistance measuring at the beginning of the charging process, so the information you need is there on the LCD without having to wait for it to appear.
Displays the voltage, not the battery voltage tough but a charging voltage as the charger doesn’t have voltage sense.
Function as USB output device, can charge your mobile phone, gopro or any devices powered by USB port.
Nice soft touch material on the outside.
No spinning fan inside so no fan noise which usually audible in quite room.
Reversed protection protected.
2 USB output ports, i think 1 port is enough but i think XTAR is being generous that they gives us 2 Ports.
12v 4A Adapter is provided.
Temperature probe, you know how hot your batteries are and the temperature reading are also available on the LCD.
Bright and sharp LCD and good viewing angle, also has auto dim function. to wake it up just press either CH/CH2 buttons.
Nice white with blue fresh design different compared to other tired all black design, look different and interesting.

No Accumulative capacity so you dont know how much capacity you put back into the battery.
Ringing sound when charging probably the inductor, really subtle no intrusive or annoying.
No incremental charging current you stuck with 3 current options.
No discharge function and measure capacity.
External power supply, this could be cumbersome.

Cannot charge Ni-MH or Ni-CD to be fair this charger probably meant for Vaping or Flashlight communities so lacking Ni-MH charging is probably a decision made by XTAR to reduce the cost somewhat, but this make the charger not the ultimate charging solution. I still have use for AA Ni-MH such as my camera speedlite but all of my flashlights are lithium powered.

Positive contact toward the front of the charger, for some this could be annoying as most charger has negative on the front side thankfully charger is protected from reversed insertion so no harm done.

Some observation i made.

Notice: this is just some measurement and observation made with amateur tool.
Ampere draws from the AC outlet when charging. as you can see the 48watts is just enough that is if the power rating is true. On the right side is a measure vs stated charging current that the charger is outputting.

When charging 2 slots at 4.1A and 1 USB output is use one of the Charging port will reduce the current to 2A. if two USB output is use both Charging will reduce to 2A. There are 2 USB ports and each port is tied to each charging ports. So in total the charger will not draw more than 40 watts from the wall.

the big gun, but probably to much even for parallel charging 18650 battery. Each can charge 30A and 40A without braking sweat.

I have been using this ISDT to charge my 18650 at 4A

Charging my 18650 at 4A, hot i tell you.

The white box, the material is excellent feels expensive, the same feel as the box you got from the more expensive smartphone and also has weight to it thanks to 4A power supply/adapter. On the lower left there is XTAR counterfeit scratch code. I haven’t test if mine is genuine :smiley:

The box on the front side

Text on the back of the Box

Battery sizes and the chemistry that this charger accept, no 14500 and no 16350. Notice the 20700 and 21700.

This charger will activate your over-discharged batteries by charging it slowly.

The right side of the box

Another box inside the outer sleeve box with XTAR name on it.

What inside the Box, 12v 4A adapter and the charger.

The charger itself

The included adapter has pilot lamp but doesnt seems to work/light up, but the adapter itself is working just fine.

DC Jack to power the charger with center positive on the back side.

Underneath the charger, no fans just vent holes

The sliding mechanism only small travels that is why it wont charge a smaller battery. i found it to be smoother than most.

Temperature probe made of metal that is curved to match the curvature of the cylindrical batteries.

LCD when battery is inserted, there is 5 seconds delay before the charger recognize the battery and start charging.

When the charger is start charging then it displays the information

In the beginning of the charging and only in the start of the process, the charger will displays iInternal resistance of the battery and it cycles through between battery percentage and IR then it only displays the percentage.

Samsung 30B charging.

Notice how hot the batteries are at 4A and this is charging 26650 at 1C now imagine charging 18650 at 4A i’ll probably stick to charging at 2A for 18650s good to have extra power when needed.

Charging 2x26650 at 4A each, it shows 100% and green light when full.

What it is look like when charging 2x26650.


Overall this is a really nice charger, with different look compared to all other tired black design. The UI is simple, choose your current and set your are done. Adapter is supplied so you are ready to go. LCD is bright and sharp with good viewing angle. Despite its lack of charging smaller battery and other chemistry such as Ni-MH/Ni-CD and no small increment in charging current its simplicity and its power what makes this rally an interesting charger. I am really liking this charger.

Charging at 4A is making the batteries really hot, i think adding a small fan underneath the battery cradle to create a small air movement will helps a lot, i doesn’t need to be fast just create some movement of air. The charger itself doesn’t have cooling fan for the electronic because it doesn’t need to, i found even at 4A x 2 charging the charger remain cool and the provided power supply doesn’t get hot either but the batteries do get hot and needs some cooling.

Video review for more detail on the Charger

Thanks for the review. I’m interested to see HKJ’s review, as I’m interested to know what safety features there are to prevent charging of a **fire battery at 4A.

Thanks for the review. I’m interested to see HKJ’s review, as I’m interested to know what safety features there are to prevent charging of a **fire battery at 4A.

at first after read the name i though that it was a 4 bay charger

Thanks for the review. :smiley:

i really like the temperature sensor, i think that every new charger from now should have that

Agree! The temperature sensor is cool!
Looks nice. Not the boring black like every other charger.
Thanks for the review mate

thanks for all the replies.

I am not sure about the automatic current selection, i am not aware that such feature is included in this charger? at least nothing mention in the manual or maybe i am missing something?

XTAR also mention of sending one unit to HKJ, for those who wants a technical review should wait a bit longer.

Thanks for the review. Interesting to see a different color on a charger, not always black plastic.
I had xtar chargers before but fully converted to hobby chargers now. Have a few Liitokala for smaller applications.

Hey rizky_p,

I won this charger in a giveaway and I received it several days ago. I decided to enhance the air ventilation on my unit so I started disassembling it. When I lifted the main pcb(the one below the display), I noticed that there is a resistor which is not soldered properly or was damaged by something.

Can you please check your unit and tell me if this resistor is soldered properly, because at the moment I’m not really sure what to do with it, should I solder it back or leave it this way.


Hmm that doesn’t sound good especially for charger at this price. I’ll check mine and report back.

Update here it is.

shot of the whole board. soldering looks fine but there are many solder blob splatter all over the board might have to clean that up.

part of the main board,

this is the same part where you have your resistor not properly soldered, mine is fine. i have few what looks like solder blobs all over the black plastic. i didn’t notice that when i opened the case will have to get inside to see what it actually is. UPDATE: apparently what look like a solder splatter on the black plastic is just some soldering flux or glue.

Thanks for the photos, rizky_p! After comparing them carefully, I also noticed that the top resistor is completely missing on my unit?!

Judging by the scratch marks around these two resistors, it seems that they were removed on purpose and by force. I’m even more confused now… I already asked the representative of Xtar in the forum about this, but it has been several days now and still no answer….

yeah you do missing one resistor :question: that is just weird. That part of the board i think is part that control the LCD?

100ohm and 10k resistor and a transistor, looklike they control some low current stuff (led, fan, not sure)

i have contacted XTAR too but haven’t got any response from them. I just want to confirm that the review unit they sent me has arrived. Probably on holiday.

Meanwhile, I re-soldered the one resistor back in place and found a replacement for the missing one. Tested the charger again, but I really couldn’t find any difference in terms of how it functions or what it shows on the display.

does your LCD auto dimming function work before soldering back the resistor?

Yes, I can’t find no difference.

2 is indeed generous but how reliable are those ports? I’m curious to see Henrich’s take on this.