MiBoxer C4-12 Intelligent Battery Charger Review

So far, I’ve been very pleased with the MiBoxer chargers that I’ve used and reviewed. Today, (with relevance to the day you’re reading this) I’m examining the new MiBoxer C4-12 charger, which has the ability to charge at twice the power of their previous chargers. 

MiBoxer C4-12 battery charger

Everything’s There

MiBoxer C4-12 package

So in the picture you can see that along with the C4-12, is a user manual and two sections of the power adapter, which with an output of 5A, is responsible for a faster charge than most other units are capable of. The only thing they don’t include, is a USB cable.

Features of the MiBoxer C4-12

Battery chargers of the 21st Century have become extremely intelligent. And although I’m not responsible for the ingenuity behind this charger, I’d have to say it’s no exception. 

Noteworthy features of the C4-12 include; 

Back of the box

  • Compatible with most Li-ion, NiMH & NiCD rechargeable batteries
  • Charges a myriad of lithium batteries (IMR/INR/ICR) including the most popular sizes; 16340 / 18350 / 14500 / 18650 / 26650 
  • Large slots can accommodate 26650 cells comfortably
  • Includes a powerbank option to charge other external devices
  • Fast-charging with a maximum output of 3A
  • Automatic and manual selection of battery current
  • Monitors battery temperature to ensure safe charging
  • Easy to read display shows all aspects of charging process
  • Restores “zero volt” lithium batteries 

C4-12 Parameters 

  • Size; (in inches) 4.75 x 6
  • Weight; 10.66 oz
  • Input voltage; DC 12v/5A
  • Output voltage; 4.20 (Li-ion) 1.48v (NiMH)
  • Output current; 4@ 3A (Li-ion) 4@ 1A (NiMH)
  • USB output; DC 5v/1A
  • Not compatible with LiFePO4 cells

Everything You Need to Know 

Power ports

The LCD display is your “at a glance” information center! Once one or more batteries are placed in the bays, you’ll get instant knowledge of the following;

  • Battery temperature
  • Current voltage
  • Per slot icon showing an “active” charge
  • Indicates which type of battery is in which bay
  • Shows battery resistance
  • Displays percentage of charge 
  • Shows elapsed charging time
  • Indicates current “mAh” in real time
  • Displays total “mAh” when complete

Using Your MiBoxer C4-12

Place anywhere from one to four batteries into the bays, and watch the C4-12 spring to life! It will be obvious as to which bay the information on the display is referring to, since “C” (followed by the corresponding slot 1) is seen next to one of the “flashing” bolt icons. For example; “C1”. 

Press the “SLOT” button to toggle through each active bay. Certain information automatically toggles as the progress goes along. 

The C4-12 sets the charging current automatically, based upon the type of battery and its total capacity. Through the course of the charge it will fluctuate, starting low and usually getting higher with time. Sometimes, particularly with a large battery like the 26650, the rise will be quick. It’s with THIS type of battery that its 3A charging limit, is possible. With smaller lithium cells, it’s recommended to allow the unit to set its own current! 

When the charge is finished, “FULL” toggles with accumulated capacity on the display, and the percentage reads 100%. 


Two batteries charging

Completed charge for the battery in SLOT #1

MiBoxer C4-12 with different battery sizes

All battery sizes fit

Even 26650’s fit well














Please note from the image above with the arrows, that the “battery voltage” display toggles between voltage, amps, and resistance.

Setting Current Manually

Overriding the automatic current is easy, but as I stated earlier, I wouldn’t recommend it for lower-capacity batteries. 

After a battery is inserted, or even while it’s already charging… press and hold “slot” for about three seconds. The “current” readout will flash. Release the button and press it again… until the level of amps that you want is displayed and flashing. 

The choices for an NiMH/NiCD battery are;

  • 0.1 – 0.2 – 0.3 – 0.4 …. all the way up to 1.0

For a Li-ion, the increments are as follows;

  • 0.1 – 0.2 – 0.3 – 0.5 – 0.8 – 1.0 – 1.5 – 2.0 – 2.5 – 3.0

MiBoxer Recommends…

MiBoxer recommends using the included adapter. But since it includes two sections, it might be a tad bulky sometimes. For that you can use any 12v adapter as long as the plug is the same. The only difference will probably be that it won’t be able to charge at 3A. 

The MiBoxer C4-12… In My Opinion

It’s a very good charger and has a lot of useful features. If you’re trying to compare this to other MiBoxer models, it’s a bit different from their C2-4000, which is more of an analyzer and adds a discharge function. And it’s VERY different from their other 4-bay unit, the “first” C4

The C4-12 takes good care of the batteries it’s given. It monitors the internal temperature, and should it rise to 60°C, the current will be reduced to prevent battery damage. Going a step further, if the temp rises to 70°C … it’ll stop charging and “Err” will appear in the display. 

The powerbank function is cool, and works with any large capacity lithium cell placed in slot 4… and a USB cable. And just to be clear, it doesn’t require an AC connection. 


I’m recommending the MiBoxer C4-12, and am confident that you’ll be pleased with the performance. 

To get one…. just click here and you’ll be transported to its product page on Amazon.

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  1. I got a mix of low and high capacity of 18650 batteries, if you put a low capacity 18650 (say 1800 mah) in it, will that be charging at 3A automatically?

    With just 1 button it will be quite painful if I need to change the current every time i use it.

    • Hey Derek,

      The C4-12 is a very good charger. The way I use it, is to let the unit select its own current. I never change what it thinks is the best way to charge. Whether it selects a very high current, is dependent on the battery. The unit takes many factors into play when deciding how quickly to charge a battery. Chances are, you won’t see much 3A charging unless you’re doing an IMR battery. I saw it recently when charging high-drain unprotected cells. Since the majority of 18650’s I own are protected ICR’s, I don’t see it much at all.

      I’m not sure what brand your 1800 cells are, but if they’re older, or lower quality, it won’t use anything higher than 800-1000mA. You can put in 4 cells of different capacities, (ICR/IMR -etc) and it’ll choose the best method. I believe it’s best to allow it to make the choice itself, because obviously it’s safer that way. If it begins a charge at only 100mA (which of course seems VERY low) it’s doing it for a reason, and most of time, it’ll increase. Even changing the current, doesn’t guarantee it will remain at that level through the entire process.

  2. The batteries I got are vaping batteries, like Samsung 30Q, Sony VTC5a, so those are unprotected cell. I have ordered the charger and from what most people say, the automatic charging should be fine. As a safety precaution I simply wont leave it charging overnight.

  3. This “charger” will NOT discharge ANYTHING. Discharging IS MANDATORY in this day-and-age. NOT that you care one flying duck, of course, dearest “Reviewer”.

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