small high power NiMH cells

**DONOTDELETE** · May 12, 2002

anyone of you experts out there know of NiMH cells designed to deliver very high currents, which smaller than the 3 Ah sub-C type of cells offered by the established manufacturers for power tools and electro models?

I am looking for something in AA or 2/3A size, is anyone out there aware of such a cell? I know there are NiMH cells available in these sizes but they are not really designed to deliver much more than 1 or, at the most, 2 C without heating up.

I want to build a small but high power diver's light using these cells. Using sub-C cells would make the light too heavy and bulky. Nominal voltage should be 24V (i.e., 20 cells) allowing me to overdrive a 100W halogen bulb to about 150W using a step down switcher, so the maximum current should be around 7 / 8 A.

wus

springnr · May 12, 2002

NiCad gives up current better than NiMH.

Can't help with bulky problem but since it's to be a diving light - you could design the case to be almost buoyant.

lemlux · May 12, 2002

Wus:

Industrial Liquidators is still selling lots of 10 @ 6A Cell 2100 mAh battery packs for $25.00. That's 60 A cells (same height as an AA but larger 17MM diameter vs. 14.3 mm.

I'm ganging some battery packs to provide 7.2V and 14.4 V battery packs.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1352164315

Ron Schroeder · May 13, 2002

Hi,

The highest capacity AA that I have seen is 2000mAh, A is 2700mAh, 4/3A is 4000mAh and 4/3 "fat" A is 4500mAh. The highest capacity 2/3 A that I have seen were only 1000mAh.

What run time are you looking for?

Klaus · May 13, 2002

2000ma AA´s ????

From whom ? marketing 2000mas ?

Talked to my local shop guys today when I by accident found some 1900ma in the close-out bin - answer - oh we bought them as they were 1900s (they do carry 1700 Sanyos and 1800 Ansmanns) - tested them to be 1500-1600 and are selling them off cheap - the Sanyos at claimed 1700s are more like 1800-1900ma.

I do like my Sanyo Twicells too though ;-)

Klaus