Won a MiBoxer C4-12 Xmas 2017; it's dead now (2020)

I finally got a chance to use my MiBoxer C4-12 that I won in the MiBoxer 2017 Christmas/New Year 99% off RRP Promo

I would like to thank MiBoxer and tatasal for arranging this!

Forgot to take a photo of the box it came in :person_facepalming:

The charger itself:

Plastic construction feels good. Display is protected by a thin film.

Size comparison to my other chargers:


From top left, clockwise, MiBoxer C4-12, Zanflare C4, Technoline BC700, Nitecore D2

Powersupply:

This has a standard ā€˜fig 8ā€™ connector for mains supply.

I was a little concerned about the safety of the UK plug supplied:


A 13 amp fuse is the incorrect rating for this product, I replaced it with a 3 amp. I have dozens of fig-8 cables so will probably swap the one supplied with a higher quality moulded plug.

Plugged in:

White balance on my camera was off, in reality, the backlight is more of a ā€˜grey-blueā€™ than the blue of the photo.

Backlight dims after about 1min 30 seconds:

In use:



Pressing the ā€œslotā€ button cycles the selected slot. The display automatically cycles between current/Voltage/internal resistance.

I tried AAA nimh, AA Nimh, 14500, and 18650, all fit fine. The cell sliders are by far and away the nicest I have ever used, they are super smooth.

The extra thick cell wrap on the AmpMax cell required a little care in positioning for the negative contact to fit.

All-in-all an excellent charger, thanks again to MiBoxer and tatasal for running the promo!

Ok, photos fixed :person_facepalming:

For me, the best thing about this charger is how smooth the contact sliders are. Cell temp is a nice addition to have.

Setting the current for individual cells is easy but having had a play around with different cells, Iā€™m quite happy to throw cells in and let the C4-12 decide on the current automatically.

Does it fit D size battery?

Well, sorry to report the charger is dead, maybe charged a couple of cells once a week, it was good while it lasted.

I put a cell into the charger and the display shut off. Trouble shooting lead me to the fuse in the UK mains plug. Replaced the fuse and turned the charger on, fuse blew again immediately.

Distmantled the charger to see if I could spot what the issue- pcb looks fine with no burn marks or anything :question:

Itā€™s currently in a bag in bits, as I canā€™t work out what is wrong with it, I canā€™t fix it! I also donā€™t think I trust this thing again, even if I do manage to fix it.

Shame because it was a nice charger :frowning:

Iā€™ve tried a couple or 3 models from Miboxer, and I like them (end charge voltage is always very close to 4.20v, which I consider as a mark of pretty good quality ā€” in contrast with Liitokala chargers which I tested, tends to veer quite a bit farther away from 4.20v).

But they seem to have a few flaws, probably due to using some not-up-to-par parts in some units.
Thereā€™s the report that the MOSFET (blows/burns) becomes defective in one of the slots (mentioned in one of the other Miboxer C4-12 message thread here).

My Miboxer C8 has been trouble-free, and I use it frequently (I like the auto-current selection, and max 1.5A and auto-balance charge current).
But lately one of the slots always gives high resistance and results in very low automatically-selected charging current ā€” Iā€™ve cleaned the contact points on that specific slot, but it didnā€™t help. So maybe the high resistance issue is inside the unit? Only occurs in 1 specific slot (I use flat-top batteries, not button-tops). Although the other slots seem to have (slightly) increased resistance compared to when the unit was new or a few months oldā€¦ But so far, still usable, other than the slightly increased resistance (and 1 specific slot that has very high resistance).

It is indeed a shame as I quite liked it, reluctant to buy another now Iā€™ve had this problem though.

Well you got some years of use out of it. Sounds like a dead short somewhere causing an open circuit when you plug it in. Mayne something in the mains side failed in the power supply and toasted something. Maybe try a new power supply?