I initially got into LED lights and Li-Ion cells because it was coming up on the time to buy new NiMh cells; or so I felt. They just were no longer performing as they did when they were new. So I have 20 aging NiMh and I have no doubt that some are good and some are junk. I do have a no/no go meter but how long should I wait before gauging them? I freshly conditioned then charged them all over the past few days. OK, I’m assuming I should wait for a period of time but maybe that’s wrong.
How do I proceed? How would you proceed? BTW, I no longer have much use for these, but as long as they’re good I want to keep the good ones just in case I need to put the old lights back into use.
without a meter?
I would use y highest demanding flashlight with a new good cell and see how long it runs
Then test the old cells comparing the runtimes with each other and the good cells.
Decide after what needs to be tossed.
I have over a dozen old NiMH AA cells of various brands - Duracell, Energizer, Rayovac, some random OEM cells that I pulled out of a small tool pack. I thought I was going to throw all those away when I bought some Eneloop Pro Black - the BEST NiMH out there! But, I still have them lying around. And like you, I don’t really have a lot of use for AA since getting into Li-Ion. The few times I use NiMH AA for testing out a circuit or whatever, I find myself using the old cells still, instead of pulling out the Eneloops. So, really, the Eneloops very rarely get any use at all, and they were very expensive, while the “junk” cells get used almost every time. Probably, somewhere in the back of my mind, it has to do with “using up” the old before starting to use the new. But really, it makes no sense at all. My advice to you is to find someone to give away the old AA format lights that you have in your collection, cells included, and a charger, if you’ve got any to spare. Don’t be like me. Be better. Be decisive and ruthless with your old cells! :smiling_imp:
The no/no go is a type of meter, but I do have an electrical meter if that would work better.
Hmmm, The Opus has at least 2 testing functions. I bet that’ll work for the NiMh as well as the Li-Ion.
Guys, they’re C cells. I don’t know of anyone who uses C cells. Good idea for the AAs I have though. I might need to buy some of those Black Eneloops. I have some remote thermometer sensors in various outbuildings and outdoors, and they take AAs. Or maybe just bite the bullet and buy primary Li. But I’m tighter than bark on a tree with some spending and I hate buying throw away batteries.
OK, did a quick test on 4 of the AAs. I got (all milliohms) 723, 1061, 143, 774. What would a “recycle it” reading be for this type of battery. Just ordinary NiMh rechargeables, not Eneloops.
I don’t expect these cells to burst into flames, I’m just wondering if there is a guideline to follow.
I have a liitokala 300, i checked the capacity and internal resistance. Also charge and leave for a month and see how much charge is retained. I have a bunch of decade old and older NiMH batteries, none eneloop, they are all junk, either accept 2-3x their capacity without getting warm or fully charging (suggesting chemical reaction inside the battery, not good), charge fine but drain themselves in a few weeks, have maxed out the internal resistance or just won’t work properly in devices like a newer eneloop does. This is how i decide what to get rid of, since its just not worth the hassle.
For C cells, I’ve been giving motion-activated night lights
that use 2x or 3x-C cells to older friends who are often up in the middle of the night.l
(these are getting hard to find, most of them out there now use 2xAA)
I take them apart and put amber/yellow color filter gel (theatrical product) over the white LEDs so they don’t ruin their sleep.
(often adding the little plastic AA-to-C converters, so they have a choice)
And there’s always the M@g C cell light with a PR2 replacement LED.
I’m guessing that high resistance cells are just as bad in this chemistry as they are in Li-Ion, so they’re gone, correct?
And the low capacity cells should also get recycled.
All of the AA numbers look horrible to me, but I don’t have new ones to compare them to. Can someone check the resistance of a new AA for me? Capacity too if you wouldn’t mind. I have 2 types, RayoVac 1600mah and Energizer 2500mah.
The C cells are all Tenergy 5000mah cells. Scanning the list, I’m thinking recycle everything under 4000mah and over 100 ohms. Comments? Again, I don’t have a new one to compare mine to.
Now they’re sitting to see if they self discharge in a month. 2 weeks left for that test. I’m not going to recycle anything until that test is complete.
I don’t know about C cells, but I have some numbers for AA cells.
If you check my website where I post my AA batteries’ cycle count test results - http://aacycler.com/result/aa/ - you can see that a new cell starts out at around 20-50 mOhm and performs well until around 100 mOhm.
Bear in mind, that I use an internal impedance meter that measures the AC internal impedance at 1000Hz, not the DC internal resistance that most of the analyzing chargers measure. The DC internal resistance should be slightly higher, but still close…
Also note that the internal resistance differs for a fully charged and fully discharged cell. The older the cell this difference can be as big as 2-fold.
OK, so all of the AAs are junk, and I’ll have approx’ 8 C cells remaining. No wonder toward the end of the use of those lights they weren’t working decently.
AA’, where are you located in Slovenia? I have a couple licensed in Ljubljana working on building a satellite company to handle EU sales and manufacturing of my products .
In the 0perating manual of the Opus BT-C3100 they are stating up to 500 milliohms of internal resistance is ok , but for remotes and things like that.
For “GOOD” quality batteries 20 to 80 millohms is considered “good”.
It seems to me though I read somewhere else that about 150 milliohms was max as far as the “safe” level of internal resistance , as it should go for “high drain” items, been too long and slept a few times since then.
Anyway if it could possibly help to read where I got the info from , then go to section 8 and sub-section 8:1 (operation modes) in the manual and it goes through a lot of stuff there.
Thanks, I’d forgotten about that explanation in the Opus manual. That’s what I used to test these cells. OK, so as of now I have 2 AAs that I’ll use until I get off my butt and order some eneloops.
I’ll also test the refresh function of the charger to see what happens to the cells after it’s had it’s way with some of them.
I think I would have kept all your C’s and trashed all the AA’s .
My experience is that the Chinese AA’s work pretty well right out of the box but fail or fall on their faces pretty quickly .
I avoid rayovac and energizers …. & the only real reason I ever had them was because they showed up super,
super cheap .
At one point I bought 4 packs of AA’s for a buck…I sold most but ended up opening and using a couple of packs .Most died fast or became about as useful as a dull stick . I regret ever trying anything that wasn’t made in Japan.
I haven’t trashed anything yet. I’m playing with the charge/refresh function of the charger to see what it does. Yeah, I bought those AAs because they were available, not because I knew anything about them. But it was the C cells that had me question them all. I’d fil the light with freshly charged cells and the light simply wouldn’t last very long. The C cells take close to forever to charge/refresh so the data is comimg in slowly.
I have some data, see above. The values to the right are after allowing the Opus charger to have it’s way with them in the “charge/refresh” cycle. Some dramatic changes are seen. I’m going to run the same cells through the same cycle again to see what happens. The C cells take almost forever to complete the cycle.
BTW, I never started this thread with the intention of doing this. I simply wanted to trash bad cells.
I did some more testing after additional “charge/refresh” cycles in the Opus. See the data above. Additional data points were acquired after each charge/refresh cycle. I don’t see most of the AAs as being worth much, even after the additional refresh cycling, but the C cells are surprising. They seem to respond to it. It takes them quite a while to do a charge/refresh cycle, but I’m not doing it. I just put them in, select the mode, and walk away.
FWIW, I refreshed these cells regularly with the MAHA charger.
I’m going to conclude that most of the AAs are junk (for me), but I’m seeing the C cells as not worth recycling out at this time. They just need to spend some time in the Opus.