Nickel Cadmium batteries........this is wierd

I have this Black and Decker cordless "dustbuster" vacuum. The rechargable batteries have developed a "memory", after a full charge they only last about 30 seconds and begin to die.

So I drained them totally dead and then charged them for the full 12 hours, as the instructions say to do if you encounter this problem.

Well, much to my expectations, this didn't work..........same problem.........

What's so wierd is that I left this thing running for about 3 minutes until it went completely dead. Just to be sure, I left it in the on positition for about 10 more minutes, and much to my surprise it started running again! No sh_t, this thing started all on its own, and began running faster and faster for another 5 minutes until it went dead again..............is this too wierd or what?

(I know, I need to find something to do around here today :laugh: )

 

Put it on Ebay - Ghost in a Drill :Brow:

 

LMAO... here we go againou:

When a battery develops a memory, what happens is a "Shelf" gets created at... lets say... half full... when you charge it fully it will die when the charge reaches this shelf... at least act like it. You just left it on and it went past the shelf down to actual bottom. but will probably not charge over that shelf now.

I usually take batteries that are going dead like this (on cell phones tho), hook them up to the car battery (full 12v right to them) and that will "Jump" them into life... at least for a little while (longest "Dead" battery I was able to "resurrect" lasted for 6 months after)

I asked a tech. for the batteries (Nokia Tech.) and that was the explanation he gave me (well... as much as I can rember, it was 4yrs ago).



I'd go the Ebay route tho...lol.

Plus find something to do...hehe:TU: :grin:

 

My digital cam is that way. I can take about 10 pics with the flash before it dies. Then it will come back to life. The first time it happened, I did the same as you and completely drained them.....I got 80 more pics with the flash on and the low battery light flashing!!!! Weird for sure

 

My r/c car (not the cheap ones you buy in the store) batteries get this all the time, although I don't jump then with 12 full volts, I just drain them completely as my charger works as a discharger if you hook the battery up and don't plug it in. A day or two and the light goes dim and then a slow 2 amp charge and it's back alive.

 

Ni-cad batteries must be "deep- cycled" when they develop memory. If you dont have the proper equipment, try a wire from the pos and neg contacts with a flashlight bulb in between. (after you discharge the battery normally). this will drain the battery down further that normal. Then charge it , and discharge it several times, putting it on the bulb, for the deep drain, at the end of each discharge cycle . If the battery is any good, it will bounce back. Leave it on the bulb when doing the final dishcharge, as long as it will light or heat up. Sounds tough, but it works.

 

I'll second that Larry!!:TU:

Same with Lithium-Ions too!! Whenever I buy a battery powered anything, I take a look at what style battery they have. I've always been told that the NiMH or Li-I style batteries don't develop a memory.

Chargers that properly condition the batteries are well worth their price.:TU:

 

many years ago ( in the early 80's) , there was an article in popular mechanics with plans for a device that would completely discharge rechargeable batteries . tried several years ago to find the article , but could not .

 

you run racing cars/trucks too?
I've got an older Losi xxt and a JRX-Pro and a Super Blackfoot loads of fun.

yea you should ALWAYS completely deep cycle your ni-cad batteries. also nicads, NIMH, LI are NOT designed to hold a charge for extended periods of time. Only lead acid/jell cell are designed to hold a charge over that length of time. so if your looking for a dustbuster and leave it pluged in 24-7 get lead acid or something similar. same goes for cordless drills, the battery type in power tools are best sutied for when you know your going to use the tool and charge it just before (up to 24 hrs) you need to use it.

for awhile there were RC car battery chargers (same cells as high end cordless drills) that were called flex chargers. they would kind of stair step the voltage to fully charge a battery. kinda like spiking a full 12 v onto any sized battery. but they would do it in a controlled fashion and repeatedly

nate

 

I've got an HPI RS4 MT w/mod motor and 2 speed (however the damn spring came out while it was all togethor, THAT was a pain in the buttocks to get apart so now it's a one speed until I find a spring to redo it). Got my little brother a rustler. That thing could pull wheelies with a gear change.

 

yea i got my blackfoot to pull wheelies with a 17 turn mod motor and the factory gearing was ok. although it breaks dog bones now. i even needed to add a wheelie bar on the back and sometimes it will lift all 4 wheels off the ground and ride only one the bar. the RC car companies have done alot and i've been out of it for quite a while now.
nate

 

If you don't have them, a full bearing set will raise your top speed by 5-8mph. I wouldn't mind getting some cvs axels either.

 

the the black foot has full BB's. it's weird I went to a hobby store auction (going out of biz) anyway picked up a tube of one size of Ball Bearings hoping they were for wheels. ended up being metric. I didnt have a use for them. (already had the xxt and the pro by then.) got the black foot for x-mas and turned out that all the black foot bearings were the same size and they were the size i got at that auction. :TU: so for 5 bucks I ended up getting a complete BB kit for that truck. there even BOCA bearings to boot.

nate