MiBoxer C4 Smart Charger Review

MiBoxer C4 Smart Charger Review

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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!

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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
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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.

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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!
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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 got while charging 4 cells was 44 degrees Celsius
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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.

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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.

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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 cell
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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!

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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.
All the 4 charging ports are separately controlled so you can charge all your different cells at once. This feature is common on smart chargers but of you have a basic lithium or NiMh charger it may not have separate current and voltage control. Also keep in mind some charger let you have no control over the charging rate.

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The Miboxer C4 has a special slot. The number 4 slot can be used as a capacity and resistance checker. These features only work on slot 4 you can insert any cell you want into slot 4 and check out the batteries internal resistance and the overall capacity.
This is great feature to have on a charger and is defiantly an optional extra that Miboxer decided to include. On high mode the C4 will discharge the cell being tested at 400ma. On low mode the C4 will discharge the cell at 200ma the charging rates stay the same so for lithium’s high will be 800ma and low will be 350ma charge rate. As with most capacity testing charger the C4 will first fill your cell up then fully discharge to 3V then charge the cell up again. The capicity and resistance checker work with both NiMH and lithium based cells.
All my cells came up close to the rated specs the charger performs the same as the liitokala lii 500. My Samsung 25r came in at 2550Mah which is very good they are rated at 2500. This charger does a good enough job to give you a ball park figure.

Mains input to DC output
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Slot 4 also has the resistance checker this feature works about the same as the Resistance testers on the liitokala lii 500. The Miboxer C4 is a little less temperamental in some aspects all the cells are within a closer tolerance. My Samsung 18650 25r get a reading of 32 milliohms. My Sony VTC5 get a reading of 34 milliohms. These readings are well within the readings that an Opus charger will give you. My personal Lii 500 charger may at times gives me a random number like 68milliohms. The figures from the C4 are more believable but it does longer to get the resistance reading.

Board is full separate from the rest of the unit.
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Another feature to highlight with the C4 is automatic activation and repair of zero voltage lithium batteries. So if you over discharge lithium cells to 0volts the C4 will slowly start charging the cells with a small current and raise the current as the cells voltage rises. This feature will autocratically shut down if the C4 thinks there is an error. Probably if the battery does not take charge. The display will show Err. This same Err message will come up if you try and charge a none chargeable battery.

AC to DC back of the board
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I will list all features here!

  • Compatible with batteries of Li-ion (4.2v / 4.35v), LiFePO4 (3.6v), Ni-MH/ Ni-Cd (1.48v)
  • Compatible with all different type of cylindrical rechargeable lithium battery
  • Up to 800mA charging speed in a single slot
  • High precision Calibration of voltage source
  • Automatically stops charging upon charging completion
  • Reverse polarity protection and short circuit prevention
  • Automatically detects battery power status and displays charging progress
  • Automatically detects Battery Resistance Detect battery capacity in discharge
  • Each battery slot controls and charges independently
  • Support small capacity battery charging
  • Support for lithium battery repair function
  • Compatible with DC12V Car Charging function
  • Made of fire resistant, flame retardant PC material Designed by optimal heat dissipation Excellent circuit design, 3 years warranty

Spring fitment is great and they feel solid
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Build quality and safety
The Miboxer C4 is a very well build charger it punches above its weight in this category. I like the internal board lay out I will attach photos here so you can see for your self. All the soldering is good and I like the fact the mains voltage is serrated from the rest of the board. There is also good separation between the AC input and DC output it looks to be about 7mm separation. All the traces are big and have good clearance. The board layout on the C4 is impressive even if I only half know what I am looking at. It looks like a lot of thought went into safety. They do mention that the charger is lighting resistant I am not sure about that. If I had an insulation tester I would love to test the Miboxer C4. Hopefully some one else with skill can confirm the board quality.

Back side battery PCB
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The Miboxer C4 also incorporates build in safety features for charging and discharging cells. Features like short circuit protection and reverse polarity protection. Which is awesome in case you insert cells the wrong way around. The C4 also automatically stops charging once the cell is full. The C4 automatically detects battery types so you will never over charge NiMH or under charger your Lithium cells. The body of the Miboxer C4 is very sturdy and is made of fire resistant, flame retardant PC material Designed by optimal heat dissipation. The springs are well connected to the charger and do not flop about when you take the charger apart. They appear to be stainless steel and are none magnetized. The negative terminal move easily and offer ample resistance they are not overly high sprung this should mean no more cells flying across the room. The buttons on the front feel tactical and offer good feedback. All the PCBs used on the C4 are custom made and have Miboxers name on them. This shows pride in there product. The Miboxer C4 also has a bleed resistor so when you open the charger it is already discharged. All of the ports and inputs feel solid and well made and do not jiggle or wiggle. The main safety issue with most charger would have to be overcharging and I am glad to say the C4 performs perfect. The other issue is to high current and here the Miboxer C8 does perfect. You know your cells are in safe hands.
Charging 4 cells at once the Miboxer C4 does get warm but not hot using my thermocouple the ambient temperate is 23 degrees. Placing the C4 on a table I saw a max temp of 44 degrees with the thermocouple under the Miboxer C4.

Front side battery PCB
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Versatility
The Miboxer C4 offers so many different features and options its a hard charger to beat. The inbuilt multiple input voltage is great plus they give you the option to use straight DC for car charging. The UI is very simple and easy to navigate. You only have two buttons and a few option all the rest is automatic. The C4 can charge all the cells that are commonly used. The charging current options make this charger friendly for all of us. The charging options also means most if not all cells can be charged on the C4. The back lite LCD is super bright and very easy to read and understand. If you do not like the back lighting you can turn it of. Not one aspect has been over looked with the Miboxer C4. Plus Miboxer give you a 3 year warranty which is a great piece of mind. Cell placement in the C4 is very good! There is enough space to fit all your cells you can even charger 2 26650 at once I have 26650 that will not fit of my other chargers but they just fit inside the C4 I managed to get in 2 26650 plus 2 18650s cells to charge at once this is awesome. Max cell lengh is 72mm which is big. The overall dimesion of the Miboxer C4 are 10.3cm across (horizontal) and 15.8cm in length (vertical) and 3.8cm in thickness.

Max charge current for NiMH is 300ma but it is reading almost 600ma this could be the pulse charging at work?
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What is included withe MiBoxer C4?

  • Miboxer C4
  • Instructions
  • AC plug
  • AAA adapter

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Overall I am very happy with the Miboxer C4 it has a few little quirks but it is a safe and trustworthy charger. It offers features that most chargers do not. I like the fact they use different charging algorithms for both lithium and NiMh cells. You are basically getting the best of both worlds. The C4 is very well built and feels super safe from the testing i have done i would have no problem using the MiBoxer C4. I have had the C4 plugged in for over a week straight and no issues even after the 20+ cycles i have put the C4 thru. From the internal board layout i can say its a lot safer then most charger on the market.

Thanks for taking the time to read my review of the MiBoxer C4 i tested the charger to the best of ability.

Regards Chris

Really wish it would let you test capacity in all 4 bays. But depending on price, I might still want one.

Seems like the only place to buy one at the moment is Alibaba. Is that correct?

Hey mate i am not sure sorry. I think they will be stocked at more locations once the company is fully up and running. MiBoxer have active reps on here and CPF the company only started in like December.

Oh, that makes sense. Thanks!

Dear everydaysurvivalgear,

Thank you very much for your time and review :slight_smile:

Great and objective,detail on each aspect :+1:

As to the current for Ni-MH / Ni-Cd,have checked max also is 800mA :
Has ‘high’ and ‘Low’ charging mode:over 500mA use high mode, less 500mA use low charging mode.
More well to protect batteries ~

Hope more people will know our factory product, welcome to contact :slight_smile:

Kindest regards,

Cabbie

Hi Cmflippen,

This is cabbi from www.miboxer.com, I contact and follow with Everydaysurvialgear
The C4 smart charger has start to sale and have stock. Goods send directly from we factory with good price, .

If interests in our charger or any question, feel free to contact. :laughing:
My email is miboxer@163.com, or sales05@miboxer.com

Kindest regards,

Cabbie