Nickel Cadmium Batteries

Why do you want to know? Every one is going away from Ni Cads due to govermant regulations. They will be obsolete in almost every country in 2-3 years. Cadmium is listed as a banned metal. ROHS reduction of harmful substances applies. Metal hydrides are replacing Ni-Cads. They have a better energy dencity.

Thanx for your info..act one of my friends was interestd in it.....btw which all metal hydrides are replacing it..cud u tell it in detail....

What other resources have you already tried?

-e

The odd thing is the RoHS standards specifically state that batteries are exempt from RoHS standards. I find that odd because

1) They are destined for the landfill, which RoHS is supposed to make less toxic.

2) They had absurd amounts of Cadmium, and that is the material that is 10 times more restricted than any of the other big 6 (100ppm vs 1000ppm).

3) The shear volume of these batteries that are consumed. If they have a problem with a cell phone with Cadmium contacts being thrown out after 2 years (yes I know that is more of a WEEE than RoHS problem) the couple of hundred nicad batteries that someone chucks in the same time frame should be much more regulated.

I know that there are manufacturing reasons and cost points that need to be considered Li-Ion isn't affordable mass producible yet, and there are legacy issues, but this smacks of saying that they are increasing jail terms for all violent offenders except for murder, which is now a fine.

BrainWave is right. This kind of battery is harmful to our bodies and our environment.So it is prohibited and is not promising.

As everyone has already told you, NICADS are out, out out!! There are better types like NIMH (already mentioned).

As you seem to be unaware of the way battery technology has progressed (and you want to manufacture!!!), here are a few points for a user.....

About the only plus point for NICADS over NIMH is that the "self-discharge" rate is slightly slower I believe.....other than that NIMH win hands down.

More energy stored per battery, no memory effects, environmentally more friendly etc etc.

Just remember the following points for NIMH:-

1) always store for long periods in an EMPTY condition - that is at the point where good electronic equipment shuts itself off - NOT AT ABSOLUTELY NO VOLTAGE AT ALL....I cannot remember what that end terminal voltage is at that point for the moment, but I am sure that someone from CR4 will tell you shortly....

2) Charge just before use and have spares available. (Spare sets if applicable. Sets must be from the same manufacturer with the same capacity, on the same charge level!)

3) Do not mix battery types nor even the exact same battery type (right down to manufacturer etc) if they are at different charge levels. The battery with the lower charge may get damaged by reverse polarisation......

4) Always use an intelligent charger that charges each cell individually. I particularly like the ones with a fan that keep the batteries cool - warm/hot is not good, electrolyte boils off easily!! My Ansmann (fan assisted) charger has "recovered" some batteries that had low capacity. Never use a charger that purports to be OK for both NICAD & NIMH (unless there is a switch over for either type). Fast charge is OK.

5) New NIMH Batteries "wear-in" and give a better charge as they get used, especially noticeable in the first few charges.

If you follow those simple points, you will get many, many re-charges per battery!

Reminds me of that commuter plane crash in Southern Illinois about 10 yrs ago. A good portion of the cause was the plane's NiCad battery. As I recall, they had a false indication that the generator had failed. They switched to the other engine's generator, but a problem with the switch lead to them not having any generator. Because it was a short flight, they opted to continue on battery with the co-pilot monitoring the battery status (voltage). Unfortunately the battery was a NiCad, which holds its voltage until just before it fails, something that the pilots were apparently unaware of. It failed abruptly before they reached their destination. Visibility was zero and without the electrically driven instruments they flew into a hill. A lead acid battery would have given them adequate warning to abort the flight to an intermediate airport.

Since you seem to know...

I replaced a NiCd portable drill with one of the same brand (Makita) using NiMH. I may go a month or two without using it. When I need it, it has no charge. Any suggestions? A trickle, perhaps...

Thanks, Dick

http://adsabs.harvard.edu/abs/1979STIN...8016488B this is a link to an abstract that might help you. If the abstract doesn't the links might.

Nicads, once a staple in aviation, are going away, I have done a number of replacements of nicads with the old reliable lead acid battery. If you have ever seen a Nicad thermal runaway(inverted voltages between cells) you would understand why. My best description is a minuture nuclear melt down. There are substantiated instances of a Nicad battery actullay burning through the battery box of an aircraft.

After a small amount of research, it would appear that a lot of power tool batteries will continue to be Nicad for various reasons.

To the Gentleman with a drill with NIMH batteries that discharges (in the time scale he mentions, most batteries will have selfdischarged I feel), there is only one answer, remove the battery always from the drill after use as there might be a small leakage of cuurent somewhere or cheap control electronics that do not switch off 100%.

Also remember to charge BEFORE you use it, most modern tools charge in 60 mintes or less, so plan a little better. To drill one hole, a 10 minute charge will be more than enough.

Learn patience!

I always buy 2 batteries, so that one can charge while the other is in use. Sometimes I buy the tool twice as it is cheaper or similar to the price of a second battery.....

I do not buy hugely expensive well known over priced names of tools either.... when the well made cheap ones are broken or wornout after 3 or 4 years use, I just thow out the broken bits (Batteries in special container of course!) and buy new. My tools get very heavy use...