MiBoxer C4 Smart Charger Review from CPF

2017-01-10
Hey folks today we have some thing different to review we have a battery charger to review. I have not reviewed a charger in a very long time! So please wish me luck!
We will be reviewing the Miboxer C4 smart charger this charger was sent to me by Miboxer they actually sent me two which is good. I have had one charger plugged into the wall for over a week straight! I have ran so many different cells through this charger in the 2 weeks I have had it. It has already had a very hard life. I have pulled one apart to check it out and left in tact for photos. 
Internal resistance test with trustfire 14500 reads 95 milliohms! sorry for the blurry pic!

I was excited to review the C4 because it looked interesting. In the looks department the Mibocer C4 look similar to the Nitecore D4 which I own. Taking the Miboxer C4 apart shows us a whole other beast the C4 is on the next level. I would like to thank Miboxer for sending me the chargers. Miboxer is a new company so it is always interesting to see what kind of market research has been done into feature that we want. Also quality is a big issue with new companies and Miboxer has taken care of that.
Capacity tester on high at 400ma discharge rate

This review will be set up a tad different we look at the following with the Miboxer C4.


  • Safety (I will do my best)
  • Functionality
  • Features
  • Build quality
  • Versatility

What category should I start with? 

Features & Functionality 
The Miboxer is jam packed with a whole variety of features it has all the goodies you would want in a smart charger. Plus extras when I was looking at the C4 smart charger I was thinking it was another plain and generic smart charger with normal features. When I received the C4 I was pleasantly surprised to see all the features the C4 offers. First of the bat I prefer chargers that have an inbuilt mains rectifier. Basically this mean instead of using an AC-DC adapter you can plug mains straights in the Miboxer. The C4 has that ability to use straight mains AC power 90-260V input voltage. No need for big and heavy adapters they are a pain. I can see two sides to this. Having an AC-DC adapter will take away some of the heat from the charger its self. Not a big issue seeing as those adapters are all passively cooled. The C4 is set up in such a way that the heat will be evenly spread throughout the charger. The Miboxer C4 stays relatively cool even charg8ing 4 cells at 800Ma. I will go further into this in the build quality section. I love opening a charger package and picking up a figure 8 cable that I can actually use. I have never received an Australian mains figure 8 cable with any charger but Miboxer sent me two. The Miboxer C4 does feature a 12v DC input this would be used mainly for some thing like an in car charger. 


The C4 can charge all of the common cell types and chemistry. This includes the following Li-ion(4.2V / 4.35V)/ LiFePO4(3.6V)and Ni-MH / NiCd(1.48V). This is going to be a very long list lol. We will start with the compatible lithium cells. I will highlight the cells that will mainly be charged by us flashlight enthusiasts. I will be honest most of these cells I have never even seen. I am sure there are some cells that are fairly common that I have not highlighted. 10340/10350/10440/10500/12340/12500/12650/13450/13500/13650/14350/14430/14500/14650/16500/16340(RCR123)16650/17350

/17500/17650/17670/18350/18490/18500/18650/18700/20700/21700/22500/22650/25500/26500/26650 


So as you can see it does all of our commonly used cells for flashlights and vaping plus lots more. We are seeing smaller cells becoming more common with flashlights like the CooYoo Quantum but those 10180 are to small to charger in the C4. This is to be expected they are really small cells. 
The MiBoxer C4 is on the larger side!

Cells can be charged at 2 rates either low or high rates. With a high charge rate capable of a maximum of 800mah for lithium/ LiFepo4 and a maximum of 300ma for Nicad and NiMH. I have actually seen seem the NiMH current go higher that is because the C4 uses pulse charging for NiMH batteries. 
I personally feel that the max charge rate for NiMH is way to low there is no reason at all that AA NiMH can not be charged at 1amp. Looking further into this I can see why they limited the input current because the pulse is phase is twice as much at 600ma. 
Thermocouple temp charging 4 cells max temp i get is 44 degrees

I am how ever pleased with the 800Ma charging rate for lithium cells this is a good compromise neither to high or to low. It appears that 4 slots can run 800Ma at any given time. Not many charger can do this even some of the more well known brands lack this quality. 
Charging cells on the low setting will yield a max charging rate of 350Ma for lithium cells and a max charging rate of 150Ma for NiMH/NiCd. Although the 150Ma is a little low even for AAA cells. I would have liked to see this option in the Lithium department so you can charge smaller cells like 10440 at a proper rate. 


Charge rates are okay overall remember just because you set your lithium cells to high to charge does not mean they will charge at 800ma. This also work the other way around I have seen the charging current as high as 850Ma. I did notice the C4 keeping the charge current lower for a bit of time then stepping up to full a charge current of 800Ma. A few times I had to go into the menu and select high charge mode again. So basically the C4 will stay on the current it thinks is correct unless you tell it to charge at a higher current. The C4 will stay on what ever charge mode you last used. This is good incaase you leave high mode on and insert a smaller cell.

From watching the C4 charge we can see the C4 is using CC/CV constant current/ constant voltage charging algorithm. So If your cells are already at a certain voltage the Miboxer C4 will drop the current. I noticed this happen at about 4.10 volts the current slowly started falling. This is actually the correct way to terminate a lithium cell. Miboxer say they use pulse charging to charge NiMh cells so I would be interested to see this in action. I do not have the proper equipment to test this. I did see the current bounce from 300ma to 600ma while charging a NiMh. I could be tripping out lol. 
Bumped the charger and it said finished lol this is the green Samsung 18650 cell


Having a look at the charging current and voltage they both seem to be spot on to what the C4 is reporting most of the time. I had instances where the cell voltage would read 4.20 volts but the cell is actually at 4.13 volts once taken of the charger. I am sure this is because the cells are under load which gives the charger a false reading of the cells fullness. So basically the cell has current put in which is making the voltage read a tad of but if you where to rest the cell the voltage would read correct. I only noticed this problem when the charger is in the finishing stages of charging. I do not think this is a problem it seem normal from most chargers this could also be my batteries or multimeter playing up. 
When you first insert a cell it reads the voltage correct 4.17 on my multimeter and the charging display. Either way this happens on most of my chargers. I ran this test a few times and got different results. I had cells reading 1.5 volts on screen and once checked while in the charger they read 1.5 volts. This does not effect the cut of voltage of the C4 which is important. The cutoff voltages are all spot on! 

Also keep in mind I am not a battery expert! 
For lithium cells the cut of voltage for lithium is either 4.20 or 4.35 (if selected in the menu). Here the C4 does very well cutting of voltage at exactly 4.198 volts. Spot on I would say! If you want the C4 to charger your cells to 4.35 volts or charge your Lipo cells you have to select that in the settings. For lithium cells standard cut of is 4.20 volts. This cut of voltage is well within the Miboxer specs. 
For NiMH and Nicd Miboxer rate the cut of voltage at 1.48 volts with a plus or minus of 1% my cells where terminating around 1.50 volts not rested well within specs. 
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