Yep.
I’ve got an almighty Miboxer (regular, not the –12) and an Opus, and I use the Ope for doing refreshes (discharge then charge, 3×) and for capacity testing, because it does it in all 4 bays at once. Think the ’Box just does that in bay 4.
Just used the Ope to test a coupla batches of EBL 14500s I got.
[quote=Lightbringer]
Yep.
I’ve got an almighty Miboxer (regular, not the –12) and an Opus, and I use the Ope for doing refreshes (discharge then charge, 3×) and for capacity testing, because it does it in all 4 bays at once. Think the ’Box just does that in bay 4.
so the C4-12 can discharge in bay 4? Am i understanding that correctly? If so, how do i do that?
No idea which version I got, but yeah, the fan’s pretty useless. When I got it cooking away on all 4 bays, it’ll start whirring away like an angry bumblebee, yet I can’t even feel the slightest wafting of warm air coming out the pipe. So what exactly is the fan doing, I have no idea. Doesn’t seem to be sucking out too much hot air.
Pffft. I think I tried doing all 4 bays at 1A, maybe 1.5A (can’t recall), but it got pretty hot and pretty noisy, and after a while it tripped the thermal breaker. Like I said, the fan’s pretty useless, so maybe sitting on top of a laptop cooler it’d fare better, but I wouldn’t push it otherwise.
I’m generally not in any particular hurry when it comes to charging, so I try to keep it down to 700mA or even 500mA per bay if I can.
No, it does not do that.
He has the older model C4, not the newer C4-12.
Good luck with that…
It’s some convoluted method like you gotta press the mode button ’til one thing flashes/blinks/whatever, then hold it or press again ’til the 3 squares on the upper-right of the display start blinking.
Setting the charge/discharge current is a whole other matter, too. I somehow just stumbled on the method at random without having to go back to the instruction book.
I don’t have the charger handy (I keep them in their respective boxes so I don’t lose anything), but maybe someone can jump in here with the actual instructions.
Usually doesn’t work with my C4-12. Manually selected override rates for my 30Qs and other problematic cells will fall back down within a minute.
There appears to be an improvement in the newer style C4 firmware though, as manual overrides do stick in that one, but it’s only an 800 mA maximum rate charger.
Wow, the older one does it but the newer one doesn’t? Odd.
Not really. The new C4-12 is a completely different design from the older C4. It has an externally mounted power supply, power brick, and the display and controls are also all completely different. The only similarity between the two is the name and the number of slots.
Well, it does if you use it as a power bank (by charging something through its USB port).
I assume they meant auto discharge and recharge analysis of a battery. Using it as a power bank is something completely different.
It CAN happen!
I have some 650 mAh 14500 IMRs that my Miboxer will automatically select a 800 mA charge rate for.
That is more than 1C, which usually produces a noticeable amount of battery heating, in addition to not being conducive to battery longevity. I let it run that way for about 3 minutes to see if it would automatically step down, but it didn’t. Maybe the C4-12s built in temperature sensors would have kicked in before any damage was done, but I didn’t want to wait to see how/if that worked.
Although the instructions I got with my C4-12 said you should be able to manually select lower charge rates like 100, 200, & 300 mA (the later being an appropriate .5C rate), I couldn’t get it to go below 400 mA with those cells installed, so I just used my 2nd Generation Miboxer C4, which incidentally also selected a too high initial automatic charge rate, but COULD easily be manually overridden to 100, 200, or 300 mA.
Just another case where a flawed implementation of uber high-tech good intentions interfere with, rather than facilitate the task at hand.
My C4-12 shuts down and reboots itself when temperatures hit about 52C. I’ve had it happen numerous times when trying to charge 4 button top 30Q cells at 3A. Although, I seem to be the only one having this issue. I have not seen anyone else report such reboots, and apparently Miboxer upgraded firmware in later versions of this chargers to automatically reduce charge rate if temps get too high, so that it does not reach the reboot level.
In hindsight, those cells that I was charging are the ones with higher IR (from Richard) - maybe that’s why they heated up so much when I tried to push 3A into them.
I do not have 4 30Q flat tops that I could try to see what temps they’d reach.
I just tried my 4 30Q button top I got from banggood in my C4-12. They only at about 4.1 volts.
I got these resistances in milliOhms:
48 reset it = 35
39 reset it = 33
40 reset it = 37
37 reset it = 39
So all normal here. :+1:
Theoretically I could maybe get lower resistance numbers by removing the button tops and solder blobing them, but it doesn’t seem worth the effort.
Interesting. This is another confirmation that Miboxer is making running firmware changes on these products, apparently without adding an easily identifiable product model/revision number change. The labels on the back of my 1st & 2nd Generation C4s look the same at first glance (in terms of Model Name/Number), but you can see a difference in the lower end of their output current specs (“V1”=350mA, “V2”=100mA). Maybe they’ll get everything right someday (or at least a little better).
My C4-12 is probably also a relatively early one, bought the day after they became available on Amazon.
I have had my 30Q reached 60C and no reboot was observed. This was during the day when the ambient temperature was in the high 20s C (maybe even low 30s). Ever since I observed the temperature getting that high, I have stopped charging my batteries with it set to auto during the day just to be on the safe side.
What’s the reported IR of your 30Q cells?
In reference to button top cells that exhibit high IR, can the button top itself cause the high IR or must it be an internal characteristic?
That’s what I was thinking. Canceled an order for BT 30Qs and ordered FTs instead.
Worst case, I’ll just solderblob ’em… :confounded:
Someone should draw 10A and measure the voltage drop across the spot weld. I think there is a good chance that is the problem.
I brought up this possibility way back when they were first ordered. I suspected that the if the weld is not up to snuff there could be problems,
These high current cells are used in tool packs where each cell is connected with 4 very large spot welds. Much more robust than the puny spot welds found in laptop batteries. But even laptop batteries generally use 4 spot welds. If these are connected with only 1 small spot weld, well……
The blue cells on top came from a laptop battery (relatively low amp draw)
The green cells below are in a tool pack (very high amps, perhaps as much as 15-20A)
Notice the size of the spot welds.
Even so, the laptop battery uses 4 welds per connection. How many are used to connect the button top?
So… would this make the cells unsafe in a high-drain application or only reduce their ability?