Probably neither. They might function normally and just give funny readings on the C4-12. We are not talking about ohms of resistance, it is milli ohms. Maybe it would reduce output in a fet driver? IDK.
What? Solder blobs should make the best contact points.
What flashlight are you talking about?
After reading all these comments it got me thinking about the 30Qs I just ordered . Here is the description of the button top Liion Wholesale attaches :
Genuine Samsung 30Q 3000 mAh batteries with a low resistance button top welded on. This is an amazing cell, extremely low internal resistance similar to the 25R but with a higher capacity of 3 Ah. A great battery for 10-50W per battery devices. As always, we’ve done extensive testing to be sure they’re authentic so you can be confident you’ve got the real thing, grade A.
The cell is made as a flat top from Samsung. Then we put on a high quality button top and wrap in a secondary layer of protective PVC.
IMPORTANT: DO NOT REMOVE THE OUTER CLEAR PVC.
These batteries were designed specifically as Thorfire Q8 batteries, but would also work great in any high discharge lighting situation or other application that needs button tops and high discharge.
I will measure their IR with my Miboxer C2-6000 when they arrive later this week.
Yeah, that’s definitely not good. Means some cells are shouldering most of the load, stressing ’em out in discharge, then being “charged” back from the other cells when the light’s off.
Which is why I wouldn’t use a “blob” so much as a wide shallow “smear”.
Well that’s easy enough to fix. Make a cross from fairly thick Cu foil and spot-weld the cells in-place, preferably on both (+) and (-) ends.
Well, easy if you got something to spot-weld it…
I used to think so too, but now I am not quite so sure.
I have noticed this with solder tops in my SRK lights and also with power banks.
Others have noticed this too and have reported it on BLF.
I know it is hard to believe, but I have pulled 4 cells out of SRK’s just after use and find each cell sitting at different voltages.
Charging them back up yields different mAh’s to each cell also.
Similarly, have you ever come across a bad solder joint on a circuit board that looked physically OK?
Happens all the time, and I STILL can’t understand how THAT is possible.
There's so much stuff going on with these charges, sometimes it makes my head hurt:
1) It's not just the Samsung 30Q button tops that exhibit problems in my higher powered Miboxers, the Sony VTC6s button tops that came with my Haikelite MT09R behave similarly, though with slightly lower, and less frequent high resistance/impedance readings and the resulting undesirably low charge rates.
2) The problems I observe with 30Qs et al. seem to be much worse when "topping up" or when charging rested batteries than when recharging THE SAME batteries fresh off a more deeply discharged state. For instance, I cleaned the contacts and inserted, then reinserted (multiple times) some Liionwholesale 30Qs that has been sitting around for a month (4.16V resting voltage) into my Miboxer C2-6000 (I decided to avoid the more extreme variability problems of the C4-12s #3 slot, and my C2-6000 seems a bit better behaved in general). They initially displayed internal resistance ranging from about about 80 to 230 mOhms, but pushing the 230 one against the negative contact spring to break the connection and then allowing it to reconnect produced internal resistance readings of ~150>130>110>90 and it finally "stabilized" at around 85 mOhms. I let them charge fully (<1A rates autoselected), then put all four of them into an 4S MT09R and drained the set to about 3.56V. When reinserted into the C2-6000 they ALL now displayed an "inset with no fiddling" internal resistance of 28 to 32 mOhms, and autoselected a charge rate of 3A (which I bumped down to 1.5A). So I let the fist two 30Qs fully charge, removed them and inserted the remaining ones that had measured ~30 mOhms 30 minutes earlier when they were still warm from the light, and they now measured 110 & 230 mOhms! By multiple reinserts I was able to got both to register as as ~88 and 110 mOhms, but they wouldn't take 3A charge rate they had when they were warm. As they charged, their displayed MOhm readings dropped to 40 and 91.
It looks like the variability we are seeing with these chargers might be being caused by more than just the possibility of any added resistance of button top caps conversions. Battery chemistry (IMR/INR etc), battery temperature, battery resting state and who knows what else may all play a role in and have an affect on how the Miboxer firmware decides to charge any particular battery at any particular time, and how much control you may be able to exercise over that process.
3 of the cells were reported by the C4-12 as 29 mOhms, one is slightly higher at 31 mOhms. See this post I put up a couple of days ago.
I will go out for another long walk later tonight with the BLF Q8 to drain the batteries down a bit, and will put it on the charger afterwards to get another set of IR readings.
I’ve measured my own batteries before and after spot welding. A well done spot welded button top will not increase IR any meaningful amount.
A new plot twist to this ongoing thriller…
*munchingpopcorn*
Exactly…. :+1:
As far as I am concerned the charger automatically choosing a charge rate is a useless feature. Just “bells & whistles” that are not needed & cause problems.
Like Jason suggested…. do away with the charger automatically choosing a charge rate. Have a set default charge rate that can be easily changed by the user. Who needs, or really wants; a charger that chooses charge rates anyway. Especially when it just creates problems. :person_facepalming:
I know I do not.
The 3A charging in each bay is a great plus for this charger.
I was & still am impressed with that. BUT after reading all this about the problems & discrepancies with the ’extra “super smart” bells & whistles’…… I have changed my mind totally about wanting one of these. 
I will pass…… 
you should review it on this theard
If you ever make a charger similar to this (4 bays that can charge each bay at 3A) but does away with the ‘automatic’ part & also measures ‘discharge capacity’…… I will be first in line to buy one. :+1: … 
My friend, if only you happen to live near me, I’d be happy to lend you my C4-12 and test its “Auto” and Manual over-ride features… I’ll bet you a few bucks that your opinion regardless this charger will not remain as such after using it.
Don’t let the ultra-conservative setting of its charging rate scare you….it only happens to cells with substantially high IR (which you can also Manually override btw) on problematic ‘protected’ cells….but it’s a breeze to use in your ‘normal’ protected cells, and more with your unprotecteds…wheeew…it’s a breeze, believe me.
^
+1
BTW the reason for the automatic mode, I believe, is for the rookies that do not know the ins and outs of rapid cell charging.
IMR type cells with low IR can take large charging currents. In fact, tool pack chargers usually charge them at rates higher than 3A.
Cells used in laptop battery packs tend to be ICR types and can not stand the higher charge rates. By default this charger uses the measured IR of the cell to choose what rate it should be charged at. IMR = low IR, ICR = higher IR
That default is easily overridden for those that wish to do so. The best of both worlds.
Also, damaged or well used or old cells develop a higher internal resistance. Those cells should not be charged at higher rates also, and this charger by default will recognize that and automatically adjust.
Hmmmm…… Thanks for that info about the ‘Auto Default’ being easily overridden tatasal & dchomak. :+1:
That sheds new light on the subject. I had assumed from my reading it was a pain in the arse to override the auto function.
I may well go ahead & get one, because the possibility to charge at 3A is very attractive indeed!!
Thanks again for the info.
While selecting the charge current manually is easy, some people reported that it does not ‘stick’:
Hmmm…. Thanks for that info Pete. :+1:
It does indeed say that.
And, if I am reading it correctly; he seems to say that was fixed on a later edition. BUT the max charge rate was only 800mAh when set manually.
IF that is correct…… that would defeat the purpose for me. The purpose (for me) being able to charge at 3A setting charge rate manually.
.
Your not reading it correctly. He said the software on the newer C4, not C4-12, has a max charge rate of 800mAh. The C4 is an older unit.
It’s also important to note that max charge rates are only used below 4v or 4.1v. The charge rate tapers off as it reaches full charge. Texas_Ace used to think the manual charge rates did not stick either, but he was usually just topping of the cells.
jmm244’s issue of the charge rate not sticking on certain cells seems to be caused by the charger reading way too high an internal resistance. When that happens these chargers can act pretty screwy.
I mainly bought my C4-12 to charge my unprotected 26650 cells as they can use that 3A charge rate and it works great for that. It really cuts down on the charge times.
Luckily all my protected button top 18650 read under 150milliOhms (120-145 usually). If they read higher, I reset it and that will get it under 150.
Maybe everyone needs at least a 2nd charger, a more basic one, that can be used for their funny acting cells?
Uh-oh, looks like there’s going to be a fight for that one, if it happens
The unequivocally positive “reviews” given to the C4-12 charger by some people sometimes bother me, until I remember that I have about 130 batteries that would lead me to the same conclusion, IF that’s all I had. Unfortunately, I have about 70 batteries that drive my C4-12 nuts, and they happen to be among my most robust, reliable and frequently used batteries. My C4-12 absolutely loves the “average” and few crap batteries I have, exhibiting few if any problems with them, even in slot #3.
Although I’d prefer the full manual approach specified by teacher, I’d probably settle for just being able to override a low charge rate on my C4-12 and have it stick. I wonder if they have addressed that problem in later versions of the C4-12 , or if the people who don’t seem to understand that particular issue just don’t have any of the batteries that cause it to show up?
I initially thought the internal resistance display capability of these chargers would be a good way of keeping track of battery ageing, but I’ve been put off a bit after reinserting the SAME battery 10 times within ~3 minutes and seeing readings from 999 to 30 mOhms. Like may other things though, the truth is in there somewhere, and you just have to learn to filter out the obvious crap readings.