Where can I find TINY NiMh batteries?

[zmoz]

I was just inside my laptop and noticed the clock battery is labeled "7.2v 15mah NiMh" and looks like it's made of 6 watch sized batteries. Where can I find some batteries like that?

 

[Silviron]

Boy, I've never run across any THAT small.

If you can squeeze them in, these might do:7.2V- 40mah NiMH at All Electronics

 

[zmoz]

Actually, I'm not looking for them for my laptop...just for random uses. /ubbthreads/images/graemlins/smile.gif I'm looking for the individual cells that make up a battery like that.

 

[Silviron]

Probably MUCH cheaper to buy the battery packs and rip them apart. It has been a year or two since I looked, but I think that the cheapest I found the individual cells was four or five bucks each.

 

[zmoz]

Yeah...that's what I was thinking. /ubbthreads/images/graemlins/smile.gif Now for the next question...how the hell do I charge those things? /ubbthreads/images/graemlins/confused.gif

 

[vcal]

[ QUOTE ]
Silviron said:
Probably MUCH cheaper to buy the battery packs and rip them apart. It has been a year or two since I looked, but I think that the cheapest I found the individual cells was four or five bucks each.

[/ QUOTE ]
You can actually buy new 40mAh nimh cells at Circuit Specialists Inc. item-H40 $1.19ea. or (10+) $.79ea.


www.web-tronics.com/ or www.cir.com/

Btw-you can easily charge these little buttons with a cheap solar charger under an ordinary table lamp. /ubbthreads/images/graemlins/icon15.gif (just use your DMM and position the charger until it puts out 4-8 mA.)

 

[zmoz]

What voltage should it be at? And how do I know when it's full?

 

[vcal]

The charger will take care of that for you.

All you need to be concerned about is applying the proper current, and using spacers (simply made of tightly rolled up broiling foil)...to fit them neatly into the usual "AA" or "AAA" charger slots.

Example: 5mA x 10hrs. = 50mA cell capacity. (C10)
Also OK:10mA x 5 hrs. = " " "

I've been using (and charging) these little cells for a coupla years now, in applications that call for the common type 357/76 cell, and they work great for almost any app. (like the Pelican L1 or the popular new Streamlight Keymate).

 

[zmoz]

So I can stick these into my regular AA charger?

 

[vcal]

[ QUOTE ]
zmoz said:
So I can stick these into my regular AA charger?

[/ QUOTE ]
Yup-as long as you can regulate the current down to 5-10mA per cell. (that's why I suggested the solar charger).

 

[zmoz]

So all I need to do is provide a small amount of amps, until I've given it the equivalent of 40mah? If I used a solar panel, what voltage should it be?

 

[vcal]

[ QUOTE ]
zmoz said:
So all I need to do is provide a small amount of amps, until I've given it the equivalent of 40mah? If I used a solar panel, what voltage should it be?

[/ QUOTE ]
Solar panels will usually put out 6v., 12v. and more. To keep it simple, and to provide about 1.6v+ to each cell, you just need to pickup a cheap AA/AAA cell solar charger.

 

[zmoz]

How about one of these with some resistors?
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F004%5F024%5F000%5F000&product%5Fid=980%2D0881
So it would be bad to provide more than 10mah for a faster charge?

 

[vcal]

[ QUOTE ]
zmoz said:
How about one of these with some resistors?
http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F004%5F024%5F000%5F000&product%5Fid=980%2D0881
So it would be bad to provide more than 10mah for a faster charge?

[/ QUOTE ]
The problem with that panel is that it only provides about 3v. total-barely enough to charge just 2 little cells at a time.

You might try REI, or Real Goods, Jade Mountain, or other camping goods stores for at least a 4 cell solar charger. It should only cost about about $10-15. -at most....

p.s.-I wouldn't try to put much more than 10-12mA into cells that small, if you are expecting 500-600 recharges out of them.