Do You Maintain *CRAP* NiCD/NiMH Cells?

[LuxLuthor]

I like Eneloops. :thumbsup:

 

[paulr]

Life is too short for crap. I recycled a bunch of crap cells but find I still have a few. If you want 'em enough to send a few bucks for postage, PM me.

 

[s0lar]

Since I have made a MAX712 based charger as part of a school project, I am checking this forum a lot.
I trew away 20 cells and still have 50 left or so.
Most of them are neglected, some are new and in better shape.
Some suffer from voltage deprevation, how can I best cure them?
One is a sanyo 2300.
I have done 5 cycles at 700mA charge and 300 to 1000mA discharge.
It starts out at 0.92-0.95V and climbs up to 1.0-1.1V after 15-45min. I still get 1700mA out of it in the end but I don't trust the cell if used as part of a pair.

 

[TakeTheActive]

Since I have made a MAX712 based charger as part of a school project...

You mentioned your school project a few times - if you haven't already, please post an overview (or a LINK).

...I am checking this forum a lot...

I noticed that you've been going through the Archives. As one who personally spent SEVERAL hours per day for SEVERAL MONTHS doing just that, I commend you for 'Hours Well Spent'. :twothumbs

...I trew away 20 cells and still have 50 left or so.
Most of them are neglected, some are new and in better shape.
Some suffer from voltage deprevation, how can I best cure them?...

Since you have a 'Maha MH-C900 clone' (which I looked up, posted LINKs about and was chastised' for going OT here: Duracell 2650mAh NiMH, test result :shakehead ), the information in Post #2 above and in my Sig Line LINKs regarding Impedance Check Voltage and Deep Discharge is where you should begin.

Too bad you already RECYCLED 20 cells - it would have been interesting to know their ICV's and CAPACITY.

...One is a sanyo 2300.
I have done 5 cycles at 700mA charge and 300 to 1000mA discharge...

IME, Deep Discharges and Forming Charges yield better results from *CRAP* cells than repeated CYCLES.

...
It starts out at 0.92-0.95V and climbs up to 1.0-1.1V after 15-45min. I still get 1700mA out of it in the end but I don't trust the cell if used as part of a pair.

You also touched upon this idea 2 days ago:

...Would it be possible that the cell reaches the termination point (1.47V) faster and faster as it has undergone cycles?... ...As the cell ages, it sure is possible that it reacts different to a charging current, making it increase its voltage faster...

and from my 'Non-Engineer / Non-Scientist' point-of-view, I attribute the faster voltage rise to 'Spent Chemicals' and/or 'Large Crystals' (blocking access to potentially useful chemicals). For #1, you're SOL; but for #2, you can 'Experiment'.

...I would like to do these test again with a different charger, one that does not terminate at 1.47V.
I would discharge in the maha after 1h rest.

If the cells are HOT (~120°F) when your PRO 1 Geniux (C9000) terminates @ 1.47VDC, I personally wouldn't switch to another charger with a higher MAX VOLTAGE - you'd only COOK the cells further. I would investigate their Internal Resistance (there are MANY methods posted) and see if Deep Discharges and Forming Charges have any effect. :thinking:

 

[s0lar]

I still have some of the cells ready to be trown away, so I will check the Impedance with my charger. The bag with crap is still sitting at home.
I find 0.1C forming charges so slow, so that's the last thing I wanna try. I will create a topic with my project later today.
Thanks for the answers.

 

[s0lar]

I just tried 3 crappy cells.
One Top Craft 2300mA gave 1.58, I trew it away because my other charger missed termination a couple of times with that cell.
Then 2 sanyo 2300.
In one I still believe.
It gave 2.68, the other gave 2.71 before both going to high a second or 2 later.
I charge them with my dumb charger and will test further after deep discharges.

 

[Lilien]

I voted with "YES", because I used over months some AAA cells in my
mouse, that were rejected by my MAHA C-9000 charger (>2,5V "HIGH"),
but otherwise still worked fine. Actually I had to keep my old crappy
charger to be able to still charge these "crap" cells.
I just bought an new mouse (1xAA), so maybe it's time to say goodbye.

Regards, Juergen

 

[TakeTheActive]

I just tried 3 crappy cells.
One Top Craft 2300mA gave 1.58, I trew it away because my other charger missed termination a couple of times with that cell...

An ICV of 1.58VDC is a nice, low number - typical of VIBRANT cells. What's its measured CAPACITY? A 100mA DISCHARGE followed by a LT 2300mAh (I'd start with 1800mAh) BREAK-IN (or 2 or 3) might 'perk it up'. What's the MAKE & MODEL of the 'other' charger?

Then 2 sanyo 2300.
In one I still believe.
It gave 2.68, the other gave 2.71 before both going to high a second or 2 later.
I charge them with my dumb charger and will test further after deep discharges.

Those 2 are pretty deep into HIGH territory (over ~2.10VDC) . I have a few DUMB 140mA and 150mA series (2 cells per channel) AAA/AA chargers that I use for cells like that. Also, my TIMED Sears DieHard 7-Hour Charger switches to 45mA/80mA/100mA/100mA for AAA/AA/C/D after 7 hours so if I don't unplug it, I can utilize those low Charge Rates too. What's the mA of YOUR DUMB charger?

"High Capacity / non-LSD / Neglected" could mean separator damage. But, if their Self-Discharge isn't too bad, they could still deliver plenty of their Capacity in clocks, thermometers, remotes, etc...

 

[Battery Guy]

I love testing, comparing performance, abusing, misusing and otherwise getting as much data as possible out of batteries....

BUT...

This testing takes a lot of time to do right, so when I do it I use good cells that have a known history. Using "crap" cells would just be a waste of time. Just like they taught you in computer programming class: garbage in equals garbage out. (Ok, give me a break...the last computer programming class I took was FORTRAN).

Anyway, life is too short and I am too busy to be messing around with crappy old batteries.

Cheers,
Battery Guy

 

[s0lar]

My dumb charger is a GP Powerbank 4, charge rate is 180mA for AA and 80mA for AAA.
Other chargers:
Memorex MRX4000: smart (-dV, max V, T and timer), 700mA AA, 350mA AAA.
Top Craft TCU-810 (no info available anywhere...): smart (-dV, max T, charges only per pair in series and 9V!), 800mA AA, 300mA AAA, 13mA 9V.
Memorex Pro 1 Geniux (MAHA 9000)
Just bought:GP 30min U-Smart: smart (-dV, timer, very picky!), 3400mA AA and 1700mA AAA and that's effective charge, I tested!
now recently a BC 700 also to do more discharge tests at the same time and charge my lower capacity AA and all AAA cells.
The GP 30min came with 2500 cells but one missed termination is 2nd charge...
It was still a good deal, I paid $20 for the charger and 4 2500 cells.

 

[WDG]

OT: FORTRAN

(Ok, give me a break...the last computer programming class I took was FORTRAN)

Heh! I took FORTRAN in '79 (was that 1979, or 1879? I forget...) IIRC, I failed. Fortunately, that means it's not floating around in my head taking up valuable space! All I really remember is doing flow-charts and those contemptible stacks of cards.

 

[unattended]

[*]Your (Active *AND* Inactive) CHARGER inventory.

inactive: some dumb to very dumb chargers that came with bad to very bad cells

mostly inactive: accu manager 10 which i suspect to be a (speak french) accu manger ; )

active: mec av4m (which is only little behind the maha c9000) and the 99% perfect pulsar 2+ hobby charger + waiting for the intellicharge i4 (i´m in a 230v country : )


[*]Your (at least approximate) *CRAP* cell inventory (i.e. Manufacturer / Chemistry / Capacity / Age / Number of cells).

accupower aa nimh 2900mah - 4x - will hold down to 800mah ! : /

activ energy (aldi) aaa + aa nimh ??? + 2300mah - maybe 4 each

minwa aa nimh 2200mah - 4x (i think those came with one very dumb charger)

tronic (lidl) aa nimh 2500mah - 8x

[*]Your current MAINTENANCE procedure(s).

cycle cycle cycle
now after reading about it here i will try to deep-discharge those ugliest cells

[*]Your SUCCESS / FAILURE picture.

cycling with the av4m brought some 20% cells back to 80 %

 

[MidnightDistortions]

Active
La Crosse BC-1000 (current/main use charger for all NiMhs/NiCad cells)
4AA/2AA Duracell CEF14N (use as backup, crap cells only)
4AA/AAA Energizer charger (emergency charger, crap cells only)

Inactive/Dead Chargers
Eveready NiCad Charger
2 Rayovac NiMH Chargers

AA's around 1000mAh (or higher) usable capacity (best batteries are on top)
4 2600mAh LaCrosse (2014)
4 2300mAh Duracells (2005)
3 1800mAh Duracells (2005)
4 2500mAh Energizer (2005)

2AA Eveready NiCad (1997 or earlier?) (200-300mAh capacity)
3AA Rayovac NiMHs (1999) (no to very little mAh capacity only works in remotes or clocks)

4AAA La Crosse (2014)
7AAA Energizers (2006)
4AAA from a Cobra walkie (2007) (360mAh average capacity)

I had no idea the Duracells were sort of bad until i cycled them in a charger and tried using them in a USB charger for cellphones, though they work just fine in flashlights, portable cd players and radios that take AA batteries. The LaCrosse batteries were just terrible from the start and had them overheat a few times in the charger on negative side of the terminal (they might have been severely overdischarged). I was shocked that the Rayovacs even hold a charge but doesn't give out much mA. Usually i'll just continually topping these batteries off, the Duracells maintain their charge for longer than any of the others (up to 3 months!) so they don't require charging as much unless i drain them. The Energizers require charging frequently (the self discharge is really high), but they perform decent enough to be put in a flashlight after being left on the charger, trickle charging for a day. I didn't add the AAA's i got with the LaCrosse charger only because i never ran capacity tests on them but they performed fairly well for AAA's in the USB charger. The Rayovac and Eveready are good enough for tv remotes. I haven't needed to recycle rechargeables yet but if any of these batteries start requiring a charge every few hours or start expanding or something to that effect i'm going to permanently retire those batteries.

 

[InHisName]

I got an Opus BT-C3100 that does amazingly better than any other of my chargers in refilling my crap cells.

Now I have 3 categories for junk cells:
1. Junk: Fails C9000 to HIGH ( > 2.12 )
2. Junk squared: Fails C9000 reboot (>2.86 approx)
3. Junk cubed: wont charge in any charger but the Opus
The most useful purposes for Junk cubed is recycling and educational experimental charging. Not good enough for even remotes.

 

[SaraAB87]

The cost of rechargables is low these days when bought on sale so all of my crap cells have gone to the recycling bin as I replaced them with batteries that were bought on sale at $6-8 a pack for duraloops or ray o vac's LSD cells. Struggling with crap cells is not fun and is a time waster. If a cell is crap it will die within 2- 3 months even in a remote from self discharge, then the remote doesn't work so every 2-3 months you have to change and charge the batteries. Meanwhile most LSD cells will last 1-2 years or possibly more in a remote (at least in the one remote I use for my tv) without needing to be touched which is awesome., especially if you have multiple remotes.

 

[MidnightDistortions]

3AA Rayovac NiMHs (1999) (no to very little mAh capacity only works in remotes or clocks)

I might have jinxed these batteries, one of them won't hold a charge or recharge.. trying the dumb charger but may have to retire one or more of these batteries for good, they are a bit shorter than regular batteries so it may have been inevitable that these batteries would finally give out. 14-15 years though from these isn't bad though it might have been shorter or longer since they have been in storage for 5-7 years.

 

[WalkIntoTheLight]

The cost of rechargables is low these days when bought on sale so all of my crap cells have gone to the recycling bin as I replaced them with batteries that were bought on sale at $6-8 a pack for duraloops or ray o vac's LSD cells. Struggling with crap cells is not fun and is a time waster. If a cell is crap it will die within 2- 3 months even in a remote from self discharge, then the remote doesn't work so every 2-3 months you have to change and charge the batteries. Meanwhile most LSD cells will last 1-2 years or possibly more in a remote (at least in the one remote I use for my tv) without needing to be touched which is awesome., especially if you have multiple remotes.

You're right, from a practical viewpoint. But some (like me) like to mess around with batteries as a hobby. I like to see how long I can keep old batteries going. I still use some 14 year old NiMH cells, and they are still useful in low-drain applications like garden lights or dim indoor LED lights. The may only put out a lumen of light, but the cells will power them for a few days. For outdoor lights, they get recharged by the sun, so I don't have to charge them up myself.

Could I replace them with some Eneloops? Sure. But, why do that, when they work well in the application I use them?

 

[MidnightDistortions]

The cost of rechargables is low these days when bought on sale so all of my crap cells have gone to the recycling bin as I replaced them with batteries that were bought on sale at $6-8 a pack for duraloops or ray o vac's LSD cells. Struggling with crap cells is not fun and is a time waster. If a cell is crap it will die within 2- 3 months even in a remote from self discharge, then the remote doesn't work so every 2-3 months you have to change and charge the batteries. Meanwhile most LSD cells will last 1-2 years or possibly more in a remote (at least in the one remote I use for my tv) without needing to be touched which is awesome., especially if you have multiple remotes.

You're right, from a practical viewpoint. But some (like me) like to mess around with batteries as a hobby. I like to see how long I can keep old batteries going. I still use some 14 year old NiMH cells, and they are still useful in low-drain applications like garden lights or dim indoor LED lights. The may only put out a lumen of light, but the cells will power them for a few days. For outdoor lights, they get recharged by the sun, so I don't have to charge them up myself.

Could I replace them with some Eneloops? Sure. But, why do that, when they work well in the application I use them?

I regularly have to recharge my Energizers in a flashlight i use daily, i for sure could just toss them for some Eneloops. It would make more sense to use batteries with longer capacities but for me it takes just a few minutes to take the batteries out and hook them up to a charger. It wouldn't make much sense to put batteries that have less than 40% charge in a device with some presets that reset every time the battery goes dead but tv remotes or flashlights are easy to recharge. I think it differs from every person and from an economical standpoint if the batteries function in a device for a day then that's good enough for me, besides saving money on single use batteries the whole point i use rechargeables is so it reduces waste. Whatever alkalines i have left or that i get from new devices i get whatever energy is left in them. I like to get whatever recharges i can out of a battery before they no longer work in any device.

In solar lights, old batteries are perfect for that application as they don't take much energy to operate. If the device didn't work as intended there is no point in using the crap batteries. Then again i am used to the regular need of recharging HSD NiMHs and ever since 2004 i stopped buying alkalines all together. While they may have lasted a long time in remotes they did tend to leak which is why i much preferred having to recharge NiMH batteries every several months or actually i shared the batteries among my devices at that point.

 

[Kurt_Woloch]

My (Active *AND* Inactive) CHARGER inventory:

Active chargers:
TRONIC TLG 500 B1 (bought at 9 EUR at Lidl)
Atari 2600 power supply (+ cord and plug contraption)
Built-in charging electronics of three electric shavers and one electric toothbrush containing NiMh batteries
Lytron 522 (only for attempting to bring up 0V cells)

Inactive chargers:
hama 46523 (sometimes used for attempting to bring up 0V cells)
TRONIC TLG 1000 B2
Robbe Netzlader 3 (only inactive for NiMh charging, but still being used for Lead-Acid batteries)
Base station of MEGACALL cordless telephone (gave up the landline)
MW MW398 (broken)

Crap Cell Inventory (sorted by age):
Robbe NiCd 1400 mAh 7.2V racing pack (6x Sub-C) from 1987 (1x)
JEWO NiCd 1800 mAh C cells from 1988 (4x)
Jewo NiCd 100 mAh 9V block from 1989 (1x)
Lytron NiCd 850 mAh AA cell from, I think, around 1990 (1x)
Ucar NiCd 110 mAh 9V block from 1993 (1x)
Practa NiCd 4000 mAh D cells from 1998 (2x)
Uniross NiMh 1500 mAh AA cells from, I think, 1999 (4x)
Nytech NiMh 2000 mAh AA cells from 2002 (4x)
GP Industrial NiMh 600 MAh AAA cells from 2007 (3x) (came with cordless phone)
Sanyo Eneloop NiMh 800 mAh AAA cells from 2010 (3x)
H+H NiMh 4000 mAh C cell from 2011 (1x)

Maintenance procedure (for both Crap and Non-Crap cells):
There's an activity scheduled in my calendar called "Recharging of non-used cells" coming up every 2-4 months depending how busy I am with other things. On each of these events, I will measure the voltage of all cells which are currently not inserted into any device and not shrink-wrapped and recharge the cells measuring belov 1.25 V using the Tronic TLG 500 B1. Cells reading 0V which are rejected by the Tronic will be put into the Lytron 522 in an attempt to bring them up to a level where the Tronic will accept them. If they stay at 0V, they will be recycled.
At this event, I will also check all the single-use and lead-acid batteries currently not inserted anywhere (and one of the lead-acids that is inserted) with slightly amended procedures.
The non-active shavers will be plugged in for charging anyway since I can't check the voltage there. The racing packs will be recharged if reading below 7.5 V using the Atari 2600 power supply contraption.

Success / Failure picture:
I think that before 2010 I didn't know how to properly take care of NiCd and NiMh batteries. Then I learned it's important to never let them run completely down in order to improve their cycle life (although many manufaturers of devices with built-in NiMh batteries say you should let the device run down before recharging it) and not to "cook" them by overcharging (at a charging rate of 0.1 C, they are full when they get warm or hot). Although I regularly have to recycle one or two cells on each event, it's seldom that cells get delegated to the "crap" pile. This happens if a new device comes into service and I need batteries for it, checking all I have if they might be up to the task, or if severe troubles occur, like batteries that are supposed to be fully charged not being able to power a device I insert them into or immediately showing "Low". I think I do take proper care of them now. The Tronic TLG 500 B1, although having been very cheap, has four slots, discharges batteries for a while before recharging them (but without letting them run completely down) and (most of the time) stops charging when they are full (or after eight hours, whichever comes first). I think more isn't worthwile with the prices of new AA, C and 9V NiMh batteries when they are on sale. I even doubt if it makes sense to do these charging events at all... maybe it would be better to just let the batteries not in use detoriate and buy new ones if I need more than I have and find that I can't revive my old ones.

 

[WDG]

All of my 2007 Eneloops went high-resistance a few years ago (all my 2008 Eneloops are still going strong.) They still charge fine in the old C.Crane chargers, and work great in lower draw devices, like clocks, low-powered flashlights, and even old transistor radios.

I could certainly replace them, but just can't bring myself to dump them while they're still useful. They're not really any additional work to maintain, as my habit is to swap & charge cells in regularly used devices on a weekly basis. The only real difference is they have to go in a different charger. If need be, I still have some "dumb" chargers around for when the C.Crane rejects them. So long as they keep working, I'll let them.

FWIW, I mark them around the top with a red marker, so they don't get mixed with good cells.