I’ve got a fancy power screwdriver, AEG, Panasonic, and Milwaukee all sell a version of it, mine is AEG with a Milwaukee charger. The chargers are made to do fast charges in a commercial setting and notorious for failing and croaking battery packs, which used to be $$$. I have an “OLD” factory battery and two different ebay clones, all say nicad 2.4v. So far my charger works on two batteries, the third fits the tool fine, not at all in the charger, so for various reasons I’d like to use my Imax B6 clone, which normally works fine, for charging and testing batteries.
Rubber band worked fine to attached the B6 clips, but the B6 was reading 4.5v before deciding the pack was charged, and during the cycle test says two of the packs only have 70 to 80 mahrs, they are rated at 1500 mahrs. I’ve tried charging at .5 amp and 1.1amp, same results. Any tips or ideas? The manual makes little sense to me.
4.5V does seem pretty high. NiMH (and I think NiCd) will be around 1.4-1.5V per cell when fully charged, so 2.8-3V for your pack. This might have something to do with how the charger detects when the cells are full. If it misses the “delta-V” it will keep charging and if the charge current is high the voltage could possibly get that high. Were the cells very hot at this point?
I am not a big fan of NiCd and NiMH because of “memory-like” effects; they seem to have to be reconditioned after they have sat for a long time. Try slow complete discharge then a slow charge (~0.2A) to try to recondition them. Possibly a couple cycles. It might be that they are very degraded and you won’t be able to get much capacity from them.
sounds like the packs are tired.high voltage and heating are the symptoms.
i have the panasonic/matsushita version(the oem for all the others)and i rebuild the packs after 4 years.
the cells had esr/ir of .27 ohms!
replacements were 7mohms/cell.
made a huge improvement in performance.
I’ve never used my B6 for NiCd Does it have a setting for total cells/series like for Li on cells—sounds like you have it set for 3 series instead of 2
Looks like the B6 is strictly peak detection, and that kind of runs away with the big voltage the B6 can deliver.
Second part of my guess is that maybe its something to do with older weak cells or even something active within the battery pack (I doubt that, other than temp sensor).
Could be the B6 is a poor choice for 2S Nicad, or maybe I just need to set some parameter that I never have. Its primary use is after all 4S or 6S high capacity hobby cells.
voltage goes high due to internal resistance.
get good cells and rebuild the packs.you will thank me later
those cheap replacement packs use cheap cells and they get beat up charging and discharging.
and you quickly find yourself where you are now.
good sanyo high rate cells will last a few years in everyday use.
Tools are designed for 2S NiCad, if I open any up they will get 1S Lion.
Standard problem with several tools I own, but rarely use, batteries age and proprietary design makes replacement costly. For now I will just live with it.
The packs get hot when trying to charge fast because they are shot and have high IR.
The B6 is trying to deal with this by upping the voltage but that causes the delta-v to terminate so you don’t get a proper fill. This is common behavior for old cells.
3 options:
New cells/pack - best option
Slow 1/10C charge for 15 hours - safest for what’s left of the pack
Bump the delta-v termination up until it seems to work - might work, might not, chance of over charging now. The setting for THIS pack would not be suitable for better packs.
Important note - There were a lot of ‘fake’ IMAX B6. They were notorious for not charging NiXX properly. The fakes could have any number of different sources and electronic components so it was about impossible to tell if you had a decent one or not without a similar ‘real’ product to compare it to. They generally seemed to do OK with lithium.
No, you cannot set cell count like lithium. NiXX charging does not work that way.
You can set charging amperage, and tweak the delta-v termination setting. That’s it. If it doesn’t work, it’s either not a good charger (see my other post and note), set wrong, or crappy cells.
The packs only get hot in the factory charger and even new packs get hot in them. As commercial tools they cared less about battery life than fast recharge times, so both packs and chargers were known to fail.
I’m sure my B6 is a fake, but no issues really so far that a normal B6 doesn’t have.
