Dewalt XRP 18v NiCad DC9096 deep cycle discharge?

[Crusader]

Years ago I worked as an aircraft mechanic [late 80's] and it was a common maintenance practice to deep cycle all NiCad's. So NOW according to Dewalt a complete an full discharge is not good for their cells? What's changed with their NiCad's. Does it have anything to do with Cobalt technology?

I just bought some spare DC9096 batteries for my "Dewalt powered drill bike"

Google it and you will see my new toy.

 

[1kickbuttranger]

I think the reason is that all the cells are in series, so if one had a slightly less tolerance, when doing the deep cycle, the cell that looses power first goes into a negative cycle (from the other cells still going through it) and it is real bad to do that.

I think I read about it on wiki..

 

[Crusader]

Yes thanks for jarring my memory. NiCad cell reversal does happen. The way avoid it is to keep a direct short or load on the cells constant until the time of charging. In aviation we used metal aluminum strips across each cell.

I've also read on a battery guru site a few years back that NiCad's are best stored completely discharged. Unless the Dewalt batteries have sort of special chemistry? But NiHM should be stored topped off.

I think I will call Dewalt and ask specifically about this. Just hope I can talk to someone who has a clue and not just reading script cards.

ps. The Dewalt batteries say made in Japan - who specifically makes the internal cells for Dewalt? I suspect Sanyo

 

[Crusader]

Another thought.

Is it better for the battery [total lifespan wise] to be stored depleted right after exhaustion then only charged when needed so the cells don't have a chance to self discharge?

Or is it better to leave them fully charged and store them in a freezer - like I do for my NiHM cells?

 

[NYEngineer]

You guys are right about avoiding a total discharge. It should be about 95%. What I do is this... As soon as a Dewalt 18 volt battery will no longer power the drill, I put it in the radio/charger. I use it to power the radio until it starts getting static and then I plug the charger in and fully charge it. I get a few years out of them like that.

 

[brianl703]

Nicad batteries have mostly been phased out. Is it possible that Dewalt is using NiMH batteries in their packs instead?

 

[Crusader]

Yes Dewalt's 18v XRP pack 9096 is stil using NiCad's. Since the packs are made in Japan I'm assuming the cells are made by Sanyo which is one of best on the market for Nicad's & NiMH.

 

[ms21043]

Are you sure they're NiCads? That kind of warning usually comes with Lithium Ion batteries, although most have built in protection that doesn't allow over discharging.

 

[Crusader]

100% sure they are NiCads.

 

[JHZR2]

Yep, I see they are listed as NiCd...

Li batteries last longest and act best if kept in a very narrow range where their chemistry is best behaved. I dont know enough of Co-based NiCd batteries (such a thing exists?) to give an answer. Usually NiCd batteries need to fully discharge.