Test/review of Miboxer C4-12

[ven]

A update around 10 months (December) a spring snapped on one of the bays. Fixed this, then another went, then another. The springs are very thin where they bend through the slider. Fitting longer cells must have put a strain over time(20700). I contacted the seller, sent a few pics of said snapped springs and received a new charger. The actual slide design looks a little different on the new c4-12, but without opening it, looks to be similar type springs(was hoping to be beefed up a little).

Only time will tell, offered to return charger but no need. So bought a spring kit off amazon and fitted beefier springs. Had to snip the ring end(one ring kept for the post, other opened up to feed through the slide neg pole.)

More resistance now , so have to be careful not to take the posts out! Other than weak springs, this charger has been nothing short of excellent. Most cells right now being charged are 26650's, voltage around 3.4 when placed on charge(Vape mod). Rate varies a little, 1.5 to 2.5a. The vtc6 and other higher drains can be up to 3a. It does pick a low rate for 16340 cells, usually 0.15 or a little higher. Still it's rare that a cell is on charge for much over an hour(not actually timed though). Of course you can manually over ride easy enough, press and hold and select rate. I have to do this with eneloop AA especially, as these get around 0.3a selected. Max is 1a for nimh, that's fine for me and that's what gets selected.

 

[Thoraldus]

A update around 10 months (December) a spring snapped on one of the bays. Fixed this, then another went, then another. The springs are very thin where they bend through the slider. Fitting longer cells must have put a strain over time(20700). I contacted the seller, sent a few pics of said snapped springs and received a new charger. The actual slide design looks a little different on the new c4-12, but without opening it, looks to be similar type springs(was hoping to be beefed up a little).

Only time will tell, offered to return charger but no need. So bought a spring kit off amazon and fitted beefier springs. Had to snip the ring end(one ring kept for the post, other opened up to feed through the slide neg pole.)

More resistance now , so have to be careful not to take the posts out! Other than weak springs, this charger has been nothing short of excellent. Most cells right now being charged are 26650's, voltage around 3.4 when placed on charge(Vape mod). Rate varies a little, 1.5 to 2.5a. The vtc6 and other higher drains can be up to 3a. It does pick a low rate for 16340 cells, usually 0.15 or a little higher. Still it's rare that a cell is on charge for much over an hour(not actually timed though). Of course you can manually over ride easy enough, press and hold and select rate. I have to do this with eneloop AA especially, as these get around 0.3a selected. Max is 1a for nimh, that's fine for me and that's what gets selected.

Thanks for the update. I just purchased this charger for my Samsung 18650 Q30's - Got a SOFIRN Q8 this week for Search & Rescue work. I'd like to keep my sets of 4 cells binned properly. I think this charger will do it.

A Very Big thanks to HKJ for the awesome technical review.

 

[hiuintahs]

I had a quick look on eBay and non of the C4 models listed have the external charger (brick) nor specifies C4-12 just C4.

Are there more than one of these?

There are a couple of different models of Miboxer C4....... the original C4, C4-12 ($45.99), C4S, C4 Plus ($36.99), C4 Upgrade ($29.99)................just to give an idea on difference in price on Amazon. There are some differences between models. You have to compare pictures and description with Miboxer's website to make sure you are getting the one you think you are. I wish Miboxer would have a comparison chart to see the differences between models.

I got the C4-Upgrade for its longer cell capability (21700). I think a couple of the other models will do that size too. The Upgrade unit also does 4.35V along with 4.20v and NimH. (I think some of the others may do that also), Only 1.5A per bay which was fine by me. No power bank feature which I was just fine with and two power sources.......12v or AC plug. I did not want a charger powered by USB when doing heavy loads. C4-Upgrade is less money than the 2.5A, C4 Plus or the 3A C4-12, but seems to do everything the Plus unit does. Also no discharge feature on this one. I may look at getting a C2-4000 in the future for that feature.

 

[ven]

Pics, older charger on left, latest on right. Can see subtle differences with neg contact and also positive(only noticed this taking the pic)

Breaks wise, the ring that secures around the post are fine, its the end that fits through the negative that gives.

No post broke so far, just springs.

 

[hammerjoe]

There are a couple of different models of Miboxer C4....... the original C4, C4-12 ($45.99), C4S, C4 Plus ($36.99), C4 Upgrade ($29.99)................just to give an idea on difference in price on Amazon. There are some differences between models. You have to compare pictures and description with Miboxer's website to make sure you are getting the one you think you are. I wish Miboxer would have a comparison chart to see the differences between models.

I got the C4-Upgrade for its longer cell capability (21700). I think a couple of the other models will do that size too. The Upgrade unit also does 4.35V along with 4.20v and NimH. (I think some of the others may do that also), Only 1.5A per bay which was fine by me. No power bank feature which I was just fine with and two power sources.......12v or AC plug. I did not want a charger powered by USB when doing heavy loads. C4-Upgrade is less money than the 2.5A, C4 Plus or the 3A C4-12, but seems to do everything the Plus unit does. Also no discharge feature on this one. I may look at getting a C2-4000 in the future for that feature.

I just bought the c4 upgrade version and the lack of temperature sensorl worries me.
It can do 1.5a which for nimh can be a problem.
I had a AAA in that had probably just finished charging and the cell was super hot, I could barely touch it.

 

[hiuintahs]

I just bought the c4 upgrade version and the lack of temperature sensorl worries me.
It can do 1.5a which for nimh can be a problem.
I had a AAA in that had probably just finished charging and the cell was super hot, I could barely touch it.

Ya, I wouldn't charge an AAA at 1.5A..........probably just 500mA max. Usually I do around 250mA on the AAA's. Do you know what current you were charging the AAA at? If the charger missed the dv/dt termination point then all the charge energy turns to heat. I mostly got the charger for the different sized cells and voltages like 21700 and 4.35v. So really haven't used it much for NiMh. I've thought highly of the charger but I haven't used it a lot. I'll have to charge some AAA Nimh to see how mine behaves and report back.

 

[hammerjoe]

Ya, I wouldn't charge an AAA at 1.5A..........probably just 500mA max. Usually I do around 250mA on the AAA's. Do you know what current you were charging the AAA at? If the charger missed the dv/dt termination point then all the charge energy turns to heat. I mostly got the charger for the different sized cells and voltages like 21700 and 4.35v. So really haven't used it much for NiMh. I've thought highly of the charger but I haven't used it a lot. I'll have to charge some AAA Nimh to see how mine behaves and report back.

I must have just missed the charging so I dont know what it was charging at. It was very hot.
It was the only one that I noticed.

 

[hiuintahs]

OK, So I charged two different AAA's at different times in different bays. And everything went well. I just let the automatic mode work and did not adjust any settings after putting the cell in. This is what I noticed. It picks a charge rate based on the internal resistance that it measures. With the first cell, it set the charge rate at 0.30 amps. I did not look at it further to see if it went up or down any because I forgot about it. When I went to check on it, charging was done. Voltage was at 1.44v and battery was cold. With the 2nd cell, I also let the automatic feature work. It said the resistance was lower and thus it set the charging rate at 0.55 amps. I also forgot to check things and found the charge completed, battery voltage at 1.44v and battery cold.

I think in the future, I'm going to set the charge current rather than rely on the automatic mode. That way I feel I have more control. I wonder if there was a possibility with your charger that the charger measured the internal resistance too low for some reason and thus put the charging current too high for an AAA. Hard to say unless you actually took note of some of those values on the screen after charging was in play. Thus what you might do is charge up different batteries in different slots and note how things are going as they progress towards fully charged. With the Eneloop NiMh batteries, I've noticed the dv/dt point to be around 1.50v. But it can vary +/-0.02v. So once the voltage gets close to that pay more attention to what is going on and perhaps periodically along the way noting charge current, voltage, time, internal resistance, & temperature via touching. What you want to find out is if you have a problem with your charger or battery, was it a one time anomaly, or a problem with a particular bay.

I'd be curious to know what you find. Since we have the same charger if there are any specifics you'd like me to do on my end, let me know.

 

[hammerjoe]

It was only one cell that I found was super hot. All the others I put in are cool to the touch.

This charger is very interesting. I wish it had temperature sensor to make sure theres no overheating. Perhaps in a future new version which will no doubt will be available or perhaps I should look at the original charger.

Anway I like this charger and I especially like the automatic charging amperage based on the cell resistance.
I think in the future when im looking for a new charger this will be an important feature I will look for.

 

[hiuintahs]

Which bay was the cell in? What you should do is mark that cell so you know which one it is and move it to another bay and charge there next time. Also I'd charge a different cell in the bay that is suspect. Could it possibly be related to the bay or maybe the cell was the problem?.............Just some thoughts.

Miboxer has recently come out with the "Upgrade C4-12" which has temperature reading displayed. Now whether it uses that in the charging algorithm I'm not sure............but I think it does based on the literature. That charger also has two yellow buttons and has some changes from the original C4-12 that make it more to my liking. I have not seen it available on Amazon, U.S. yet. Rather than get a spare Upgrade C4, I think I might be interested in the "Upgrade C4-12 as a 2nd unit. Price will likely be around $40 on Amazon is my guess.
http://www.miboxer.com/eng/p6u.html

 

[hammerjoe]

Which bay was the cell in? What you should do is mark that cell so you know which one it is and move it to another bay and charge there next time. Also I'd charge a different cell in the bay that is suspect. Could it possibly be related to the bay or maybe the cell was the problem?.............Just some thoughts.

Miboxer has recently come out with the "Upgrade C4-12" which has temperature reading displayed. Now whether it uses that in the charging algorithm I'm not sure............but I think it does based on the literature. That charger also has two yellow buttons and has some changes from the original C4-12 that make it more to my liking. I have not seen it available on Amazon, U.S. yet. Rather than get a spare Upgrade C4, I think I might be interested in the "Upgrade C4-12 as a 2nd unit. Price will likely be around $40 on Amazon is my guess.
http://www.miboxer.com/eng/p6u.html

Bingo. That might be my next charger. I will put the c4upgrade I just got on sale very quickly. LOL

 

[ven]

c4-12 are fantastic,

But the updated still looks to be the same with springs from the link pics. The weak spot being the connection to the slider neg pole. Easy to fix, but would prefer more beefed up. My vp1 and vp2 get used a lot(especially the vp1 i use in work, that is daily use for several years). No issue so far with spring/s .

But for user friendly simplicity, the c4-12 is spot on, i place cells in, no pressing, job done! Other chargers i have to press, select each time. Yes no big deal, but when using a lot, it wears thin. So these are kind of a breath of fresh air after 6 or 7+ years of charging cell/s daily.

 

[hammerjoe]

c4-12 are fantastic,

But the updated still looks to be the same with springs from the link pics. The weak spot being the connection to the slider neg pole. Easy to fix, but would prefer more beefed up. My vp1 and vp2 get used a lot(especially the vp1 i use in work, that is daily use for several years). No issue so far with spring/s .

But for user friendly simplicity, the c4-12 is spot on, i place cells in, no pressing, job done! Other chargers i have to press, select each time. Yes no big deal, but when using a lot, it wears thin. So these are kind of a breath of fresh air after 6 or 7+ years of charging cell/s daily.

I agree with you but for me is more the fact that the internal resistance of the battery matters and the charger adapts the charging on the go. I can only wonder how many batteries I have helped ruin faster because I would just put them on my litokola 500 or the opus bt700 charging at 400 or 500ma when their internal resistance was going up.

How many chargers out there take in account the internal resistance to determine what ma the battery can take while charging?

 

[hammerjoe]

Folks dont miss this oportunity.
The new c4-12 upgrade is on sale on banggood for $28.95.

I placed an order and I will be selling the C4upgrade soon.

 

[ven]

I agree with you but for me is more the fact that the internal resistance of the battery matters and the charger adapts the charging on the go. I can only wonder how many batteries I have helped ruin faster because I would just put them on my litokola 500 or the opus bt700 charging at 400 or 500ma when their internal resistance was going up.

How many chargers out there take in account the internal resistance to determine what ma the battery can take while charging?

Quite a few of the more recent chargers use IR . Only down side is button tops tend to add to the resistance, so some can get a real low rate. Of course you can manually set the rate and over ride the selected .

 

[hammerjoe]

Quite a few of the more recent chargers use IR . Only down side is button tops tend to add to the resistance, so some can get a real low rate. Of course you can manually set the rate and over ride the selected .

Can you name a few so that I can check them out?
I am thinking the RC3000 might do it but that is a beast on its own league.

 

[ven]

Can you name a few so that I can check them out?
I am thinking the RC3000 might do it but that is a beast on its own league.

Off the top of my head, nitecore sc4, this one was a close contender for me. For a list, not sure actually how many there are today.
https://lygte-info.dk/info/indexBatteriesAndChargers UK.html

 

[tripplec]

I looked at mine and don't see a version #. It has temperature displayed for the cell which I believe the V3 does not. The black embossed printing on the back of the charger is hard to read if its there at all.

 

[hammerjoe]

The upgraded version that I bought on banggood has finally shipped. It should be here in a couple weeks.

 

[Rexlion]

My Gyrfalcon has an auto mode like that; pop the cell in and the machine does the rest. But the readout only shows voltage and charge current. I like the idea of having more info presented on screen.