cheap NiMH cell for my son's toys

[viorel00]

I am an addict of Eneloops, but I hesistate to use those in my 3 year old son's toys since he'll leave them on and drain them below 0.9V, which I think might kill the cells.

I have several energyzer (1700, 1850 and 2500), duracells (2650 which are junk by the way), some LaCrosse (2000 and 2400, and some AAA 700 and 800), so I use these in his toys, but it's a pain to match them since I have sets of 4 and some toys take 3 or 6 cells.

Anyway, I was thinking of getting a load of cells of the same type (same brand, same capacity) and just set up a "kanban" system where you always pull charged cells from the front and put the freshly charged cells in the back.

So the requirements are:

1) cheap
2) can take abuse, i.e. not die if draw down to 0V or even reverse polarity (OK, they might die if you do this a lot, but take a one in a while abuse)
3) have medium self-discharge rate, not go flat in one week like those 2650 duracells.

I found deals like this one:

http://dealmac.com/AA-2600-m-Ah-Ni-...-Pack-12-AAA-for-29-free-shipping/250709.html

basically 36 cells (24 AA and 12 AAA) for around 29 bucks with free shipping, which makes them around 81 cents/cell.

I don't have any experience with the Tenergy brand, are they any good? any other options at around $1/cell that I should look at?

I figure even if the cell dies after 10-20 uses, it's still better for my wallet (and for the environment) than buying Alkaline cells.

I also plan to get a Maha C9000 charger, I have a LaCrosse BC-900 that I use now but I want to upgrade. So I can always analyze the cells and throw out the empty ones.

Anything wrong with my plan? any advice is appreciated.

THANKS!!!

 

[Mr Happy]

This is kind of an off-the-wall idea, but you might possibly consider these:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=47440

The capacity is low, but so is the price, and I think NiCd cells can take a little more abuse than NiMH. For one thing, they don't mind being drained to zero volts.

Harbor Freight used to have NiMH cells at a similar low price, but they seem to have replaced them with a new variety and upped the asking price to the point they are no longer a bargain.

 

[phenwick]

In my experience, no name or off brand cells can turn out to be junk and can not come close to the labeled capacity, or even take a charge on a smart charger such as the Maha C9000. I'm not suggesting the cells in the provided links fall in this category, but I've learned my lesson and only put my money in quality cells and avoid the headaches.

If (and a big if) I was doing this, I would order a couple of cells and see how they perform out of the pack before buying them in bulk. Better yet, shop for name brand cells on sale, and avoid potential disappointment.

Edit: Check this in the Marketplace: Radio Shack AA hybrids 2XAA $2.97
Some feel these are relabeled enloops.
http://www.cpfmarketplace.com/mp/showthread.php?t=183809

 

[AnalogDog]

I have used a number of off brands including the Energizer 2500, Sunpak, Digital, and the like. They are all on my recycle pile, as they are junk. Just use a few times and they don't charge fully. I try a reset with my Maha 9000 charger, the problem does not go away. I give up.

Look for deals on good batteries, Maha, Eneloop, and so on. I use them in my son's (4 yo) toys and I have not lost one yet. All the others are gone. I found a pack of 12 (8AA, 4AAA) 2000mAh Eneloops for $20 recently at a local discount store.

 

[mdocod]

Actually, it's the more expensive LSD cells that are going to tolerate the abuse of a 3 yr-old better than any other NIMH cell. Alternatively, "lower" capacity name brand cells. Avoid anything over ~2300mAH label ratings and the cells will be reasonably robust.

However, I am personally in agreement with Mr. Happy on this one. You can get NiCD cells for about the same cost as Alkaline cells (under a dollar each), so you don't have any guilt to worry about even if they don't last long, but more than likely, they will last a LONG time as they tolerate over-discharge without any major problems. Sure they won't have as much capacity, but with your idea of the revolving inventory, you shouldn't have too many problems. My suggestion would be to order just enough cells for all the devices, plus the quantity that the device with the most cells uses, plus maybe 2 more so if you find a dud or 2 you can take it out of circulation. Having too many cells, will result in them sitting unused for longer periods of time, and NiCD will generally have higher self-discharge rates, so using them within a few days of charging would be best.

http://www.batteryjunction.com/tenergy-aa-1000-b.html

something like that. I don't ordinarily suggest Tenergy brand cells (though I have had a mixed experience with them, some good some bad). I would expect that their NiCD cells *should* be fine.

The Harbor freight NiCD also would probably be fine.

here's some other options for cheap NiCDs:

http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=568
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1108
http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=1110

Eric

 

[viorel00]

Thanks guys, I was thinking to stay away from NiCd, but maybe NiCd is indeed better suited for these kind if situations. I will get a few and see how they perform.

 

[Ayeaux]

I've been thinking about the same thing recently. So far my son has completely discharged 8 eneloops. They seem to be working just fine however. One set of 4 have been discharged at least twice. I've had these batteries about 10 months now and they probably have about 8-10 cycles on them.
I have considered NiCd, but don't want to deal with the extra battery changes from the reduced capacity. I'd probably go with the Kodak pre-charged batteries from wal-mart at about $9.00 I think. They also have some NiCd solar light batteries with 900mah at 4 for $5.14. I bought a pack the other day and after a day on the BC-700 refreshing, they came off at around 870mah each. You might want to try a pack of those and see how they work for you.

 

[joegreen42]

Low Self Discharge is the key.. I had 1000ma NiCd's in the majority of the kids toys but if they don't work after a month of storage the kids just grab some alkaline's from my wife's battery box..

Eneloops have made us all happier!..