Hi Jim, Maybe this is specific to europe but NiCds are hard to come by here, they are prohibited since 2008 And even more prohibited since 2017 ( they also exclude medical equipment ) I used to source them in ex-ussr countries but even there they are hard to come by nowadays, quite expensive, and usually new old stock from 10+ years ago which hardly qualifies as renewing your battery pack, even if it's usually better than the 40+ years batteries. On top of that they are usually 700mAh, which isn't much by today's standards I'll be trying to shove 2400mAh NiMH in my CE150, the question remains, do I keep the NiCd trickle charge (many people did and seem to stil be alive) or do I go the extra mile and use a proper NiMh charger ( that'll blink when batteries are full and stop the charge ) You could also argue wether or not a $1 nimh charger from Aliexpress does any good to my safety. I'm surprised "replacing nicd with modern equivalents" doesn't seem to have much attention Le 2022-12-22 16:52, Jim Brain via cctalk <cctalk(a)classiccmp.org> a écrit : > > On 12/22/2022 4:08 AM, Cedric Amand via cctalk wrote: > > Hey everyone, No - I won't ask if this is on topic or not :) I'm currently reparing an ALPS plotter ( a Tandy "ce 150" equivalent ) and it's not the first time I face the same problem ; how to replace NiCD batteries. In the past what I did is actually order new NiCd ( you can still find them here in Europe, well actually out of europe but in eastern countries close to europe ) However they are at best NOS nowadays, that does "work" enough for moderate use (I've done that on vintage laptops) This time I'd like to go a bit beyond that and replace the NiCd with modern NiMH (the plotter coils and motors will benefit the extra power) However the trickle chagre of NiCd applied to NiMH will either kill my batteries or kill me in a house fire. I see small $1 NiMH 5S charging boards on Aliexpress, I thought I might use that, try to shove it it the CE150 (or other devcies with the same problem) TL-DR : Before I re invent the wheel here ; Has anyone developed a proper way to replace NiCd with N > > > > iMH in vintage (mostly portable) equipment ? And I mean not simply swapping the batteries, I don't want that, I want a proper charge process. > > I apologize that I don't have an answer to the main question on how to > upgrade from NiCD to NiMH, as I considered it for a similar portable > printer a few years back, but decided I was not willing to incur the > risk for the usage I envisioned. > > My comment has more to do with the statements about NiCD batteries you > made. Is there a size constraint that hinders finding new cells to use? > I find brand new NiCD batteries of quite a few sizes all over, as many > folks use them to re-pack portable tool batteries and other similar > uses. I've repacked quite a few NICD containing systems (Old HP > portable computer, camcorder, printers) with these new NiCDs, which all > are smaller, have more storage capacity, and are brand new. > > If you decide to continue with NiCD and send cell dimensions, I'm happy > to see what I can find that's new. > > Jim > > -- > Jim Brain > brain(a)jbrain.com > www.jbrain.com >

I can't speak with any authority on the NiMH vs. NiCd substitution, except that I've replaced them on low-draw devices and used the same charger.  After 20 years of doing this, I can't claim to have destroyed any NiMH, though I can certainly appreciate the self-limiting of overcharge on NiCd cells. On some small tools taking NiCds, however, I've substituted Li-ion rechargeables (3.6v->3 NiCd) and used the low-cost charger PCBs that are usually sold as 3 or 4 in a snap-apart package.   Those have worked well for me.   I wonder if changing a couple of resistors on those could suit NiMH charging. FWIW, I've salvaged the Li-ion cells from discarded vaping e-cigs.    Those generally are fairly high quality and run about 600 maH capacity at 3.6V.  Why they're used in a non-rechargable application is anyone's guess. --Chuck

I just read the battery chapter of the ARRL Amateur Radio Handboo, which discusses this particular point at some length. Among many other points it says (a) you can trickle charge a NiCd but not a NiMH, and (b) NiMH requires a more complex charging algorithm than NiCd, so that NiMH chargers are also capable of charging NiCd batteries safely, but NiCd chargers cannot charge NiMH cells without the risk of damage. I suspect NiMH charger circuits can be found. Buying $3 Chinese ones may work, or not; I keep remembering that China disallows selling unsafe equipment within the country but doesn't have any rules against exporting such things. paul

There are quite a few. Mouser lists 278 that claim NiMh capability. All but 9 of those are multi-chemistry. https://www.mouser.com/c/semiconductors/integrated-circuits-ics/power-manag… Will

Yes, that looks similar to what I read. One interesting point in the discussion I saw is that it said slow charging is not recommended for NiMH because the right way to detect end of charge is by voltage drop, and that drop is even smaller if the charge rate is low. So to have reliable detection of "fully charged" you need to go reasonably fast. Interesting. paul

A VERY large percentage of LiIon batteries have a protection circuit built in to prevent over-discharge. Even a lot of the "standard" cell types (e.g. 18650s) The circuit disconnects the battery from its terminals if the voltage drops too low, showing near 0 volts out. If it just barely meets the cutoff, it may recover enough to re-activate the circuit, making it possible to recharge it. Often, you can open the case, skip over the circuit board to access the battery cell directly, and add a small amount of charge to reactivate it. Then it will work normally. I've done this a few times. Will I do not think you can name many great inventions that have been made by married men. Nikola Tesla

That's American social media slang for "too long, didn't read". I guess in this case it means "summary". paul

If you can’t be bothered to read a document then I don’t think you can have any valid opinion or comment on it. Sent from my iPad