Got a new charger-Miboxer C4-12, 4 slot X 3A/slot, total 12A output

Coming soon: C4-12 v2 ( compatible with Li-ion 4.35V and LiFePo4 cells)

Add discharge/capacity-analysis and you have a useful update.

That would be an entirely different, new model.

hahaha, budgetlightforum, don't forget the budget.

Haha, BLF is no longer “the” Budget Light forum it used to be.

Give us a perhaps sub-$75 MiBoxer quality charger/analyzer, and you’ll give everyone a run for their money.

For those who doesn’t want it, there’s always the regular C4.

I don’t need an analysis feature. I don’t think I need the new voltage settings either.

We were actually talking earlier about removing features from the C4-12 in order to make it more reliable. We all like the high powered charging and all of the 11 or 12 different charge rates, but certain batteries, like button top 18650, seem to read unusually high internal resistance. This can make the charger software act funny. I like the idea of removing the automatic charge rate feature and just setting the charge rates manually. I pretty much set them manually anyway.

Or they can upgrade the firmware to not be too sensitive to high IR from protected cells so as not become too conservative in selecting the auto charging rates.

So far the C4-12’s over-sensitivity in Auto mode to high IR’ed cells is the only main concern of this otherwise superb charger, IMO.

I for one personally like this “Auto” feature very much, specially if the bugs are ironed out ( I only have 5 protecteds, btw, and all high in IR!).

What if the problem is not in the firmware? It could be in the slider design or something else.

In general I agree, Miboxer should focus on getting the existing bugs worked out of the current design before trying to add new features.

+1
If it takes a new model…. go for it. :wink:

well i want a charger with build it flashlight. :stuck_out_tongue: we got many flashlights with build in charger already

Hey guys, I got Mike’s 30Q’s in and they are reading inconsistently. They are mostly under 100 milli ohms, but one is a bit more erratic. I took off the extra wrapper and I ran into a problem.

It seems Mtn Elec button top 30Q are spot welded in 4 points. This should be the most reliable method of attaching a button top and give the least amount of extra resistance, but appearantly it’s not.

Now I’m trying to figure out the best way to remove it without damaging the factory wrapper.

Any suggestions?

Hey, I found the problem! It looks like the spot welds did not penetrate enough. I was able to take a micro screwdriver and pry underneath the tab and it popped right off. That would definitely explain the extra resistance. Now let’s hope the other three cells are just as easy. (EDIT, they were not)


.

Well………it seems that this might answer some of our questions.

Okay, after cleaning off both ends of each battery I tested them out in my own C4-12 charger three times each and they all read very consistently with low internal resistance and they all automatically switched to the 3 amp charge rate.

35 47 27
27 34 44
39 43 32
31 33 39

27 to 47 might seem like a big swing, but for this charger I’d say it’s more than fine.

Now to do the solder blobs. I don’t expect the resistance to change any but I’ll test each cell multiple times afterwards just to confirm.

With solder bobs , how would you make sure they all make contact in a Q8?

All you have to do is make sure they are taller than the wrapper. I plan to go a bit taller than usual above the wrapper just in case they wear down a little due to rubbing the brass ring on the Q8.

Following

As my ole granpappy used to say Jason……
…………………………… “that’s some mighty fine work son!!” :+1:

And it is some mighty fine detective work too!! Good job Jason…… :slight_smile:

You proved / verified at least three things I believe.

  • 1. Your are a pretty good detective.
  • 2. The problem was indeed with the cells from MTN & not the charger.
  • 3. Mike is not crazy. :smiley: :smiley: …. :wink:

Almost 4 years ago I tried to raise the possibility that it wouldn’t be a good idea to add button tops to high drain cells

and elsewhere on this forum when I brought up the subject I was ignored. High drain cells are made with flat tops so that they can be spot welded into battery packs. Those spot welds connect the cell directly into the pack, not onto a button top that has to make relatively loose contact with another conductor. Also those spot welds are very large and robust.

This question of high IR with added button tops has been coming up over and over again on this forum. Here are some links to other threads that were started on this subject.

Solved: Internal resistance increase with button top VTC6 and 30Q

Anyone else had dud Samsung 30Q button tops from BG recently?

Are the button tops on name-brand cells spot welded?

So yea. Whatever you guys do, don’t use magnet battery spacer… buy a button top or solder blop.

This is an example how much heat generated from a flashlight.