NiMH discharge

HiMh has a higher capacity, and for some old drill the difference in ESR if any probably doesn't matter at all.

you'll need a different charger though, unless yours is made for nicad/NiMh use.

"bw"

The truth is that NiCd cells are basically out of production now, due to the ban on Cadmium in the EU among other things.

There is also very little difference in the internal resistance and number of cycles that are to be expected from NiMH and NiCd.

..... Phil

"David Eather"

Both NiCd and NIMH cells can be discharged at very high rates, so high they would be expended in under 4 minutes.

People with competition RC model planes, cars and boats regularly discharge cells in around 2 minutes - a 4Ah sub C NiMH cell will deliver about 60 amps under this condition. The cells do get quite hot, of course.

Everyday applications like drills are nothing like this fast and present no problems for NiCd or NiMH cells.

... Phil

Cydrome Leader wrote in news:jdd8pu$87b$ snipped-for-privacy@reader1.panix.com:

he could also take his battery packs to a place like Primecell,Batteries Plus,or other battery pack rebuilders,and have them rebuilt. they would have the right sort of cells for power tools,and might be able to recommend a proper charger.

Li-ion cells are nice,they don't self-discharge like NiCD or NiMH. you can leave your power tool for months and when you go to use them,they don't need recharging first.

I modified my old Black and Decker 3.6V VersaPak batteries to use a

Batteries are not included in the scope of RoHS.

They are sold in the EU under the Battery Directive.

If you look at the exemptions..... Art. 4 - Cadmium Ban: Emergency, emergency lighting, emergency doors, and alarm systems; medical equipment; cordless power tools

NiCd batteries can be sold for those uses.

Cheers

Are there any references as to what overcharging and drain-to-near-zero does to lifetime and usable number of charges? Hopefully the same reference will give one an idea of use that gives maximum yield.

"Martin Riddle"

One cannot sell loose NiCd cells to the public in the EU.

Volume suppliers of NiCd cells like Sanyo ( the biggest ) ceased all production two years ago.

.... Phil

The cells used for rapid discharge are quite different from the cells used in the older notebooks.

The problem with looking up information on batteries, especially secondary cells, is the chemistry is a moving target. So it pays to look at the publication date of any reference.

I had a customer return on a charger chip once that apps couldn't handle. I managed to track it down to some Panasonic batteries that claimed a high charge rate, but in reality couldn't take the current. [Tripped the overvoltage protection.] My druthers are to go with Sanyo first if there are multiple vendors. I've never had a Sanyo battery not live up to the published specs.

"miso"

Over the years I have used various sub C and C size cells from Saft, Panasonic, Tadiran and Sanyo for very fast discharge - including 4 minutes to flat for the highest capacity sub C Sanyos ( KR-1800SCE).

Cells damaged by overheating and overcharging are another story.

... Phil

As an aside, there is a point where you should give up on "fast" charging and go to trickle. It varies per battery of course, but for c/3 or slower, it is hard for fast charge algorithms to detect when to stop charging.

"miso"

... Phil

Good link. Thanks.

miso wrote in news:jdejuf$379$ snipped-for-privacy@speranza.aioe.org:

Panasonic used to sell a cordless drill with a 15 minute recharge time. NiCds.

"smart" chargers can fast charge to a point,then switch to slow charging to top off the cell. some monitor cell temp -and- terminal voltage or deltaV.

Thanks. And thanks to all who input.

Not a problem. The current "charger" is built into the drill - a diode and a resistor + externally manually timing the charge. I'll probably improve on that.