AM I MISSING SOMETHING?

[IOWOLF]

http://cgi.ebay.com/ws/eBayISAPI.dll...Name=WDVW&rd=1

CAN ANYONE explain this?

Serious explainations only please.
I realize You pay your money and probably get scamed, I read his f/b.

[Your Old Dog]

my friend who works electronics tells me you can sometimes penetrate the thin chemical layer in the cells by sparking them with 110V very quickly. It's a long way from fully rejuvinating a battery but you will get more life out of it before you scrap it.

[pgmrdan]

There is a way to get some more life out of rechargeable batteries sometimes. You reverse charge them with a DC voltage quite a bit higher than the charge they normally have.

It's definitely not a resurrection type of rejuvenation. You may get a few more weeks/months of use out of them or they may blow up in your face so BEWARE!

I've done it to some batteries and it did work for a while. I used a 12V power supply on 1.2V AA sized batteries.

Your mileage may vary.

[This message has been edited by pgmrdan (edited 07-24-2005).]

[dvideo]

the techniques will strech out NiCad life. I think you can find everything you want to know by using google. A "zapper" is cheap to buy.

Basically.... "bad stuff" builds up. You zap it and get some additional life. Decay of charge held after one day is one way to measure. Cheap NiCads can be made to last substantially longer. Really good NiCads don't have the problem as much - less effect. If consumer product, then assume cheap....

--jr

[pgmrdan]

The 'bad stuff' is referred to as 'memory'.

The best thing to do is prevention. From what I've seen, you need to do a really good discharge on the battery about once a month then fully recharge it.

If you constantly do a partial discharge and then recharge the battery develops a 'memory' at that partial discharge point and eventually begins to stop discharging when you get to that point. It appears dead but it isn't, you just can't easily get enough power out of the battery below the memory point.

I'm sure someone else can give a better explanation but that one works for me.

[Jack Burns]

Sure. As individual ni-cad battery cells age, they slowly begin to grow little conductive tentacles from the negative to the positive regions within the cell and as these tentacles gradually become thicker and more conductive the cell slowly dies. The trick is to zap those little tentacles away while they’re still relatively young using a short-duration, high-energy electrical pulse like you get when shorting-out a fully charged high value electrolytic capacitor. Basically, the discharging capacitor produces a little lightening bolt within the cell that vaporizes the tentacle somewhat like an overloaded fuse.

Hope this helps.

Kind regards,

Jack

[IOWOLF]

JACK how do you Zap them ? as mentioned above, with 110vac? or a blast of 12 vdc like from a battery charger on boost
(40 amps)?

[jburstein]

If you google around you can find a schematic on how to build a circuit that will do what Jack describes to the battery.

-Justin

[IOWOLF]

I tried googleing ,no results except games and medical.

[aboard_epsilon]

I've Resurected 9.6 makita batts by putting 12 volts thru them for ten mins using a car battery charger.(two nails stuck in the contacts on the batt)in reality it was probably putting over 13 volt thru them.
during the ten mins I was feeling them to see how hot they got and disconecting ..when they felt warm.
I did this with a totally dead one that would not charge up at all off the makita 1 hour charger ...i thought what the hell give it a go .
and after that i tried charging it normaly with the makita charger ..the batt was as new ......still have the same one and that was over two years ago.
if you do this exersize caution !!! batts can explode if overcharged like this ..hence me feeling the temp of them.
all the best......mark

[PSD KEN]

ZAPPING with 110vac! an invitation to disaster.
I would like to watch from adistance.

[IOWOLF]

Mark what amp rate?

Ken, thats kinda what I thought.

[Jack Burns]

Hi IOWOLF

You asked whether ni-cad cell rejuvenation is possible and I did my best to lay-out the basic theory behind it while intentionally avoiding particulars. The problem is, high energy electrical components like large electrolytic capacitors and electro-chemical cells can easily turn into hand grenades if mishandled (don’t even ask how I happen to know this ) and I don’t want the responsibility of getting anybody hurt as a result of something I said here. If you want to know exactly how it’s done, I recommend a google search using terms such as �ni-cad’ or �nicad’ plus �zap’ or �zapper’, et cetera. While this search oughta provide you numerous options for building your own device from readily available parts, I just want to re-emphasize how dangerous this stuff can be if you don’t have the experience to do it properly. Anyway, good hunting. And by all means stay safe!

Kind regards,

Jack

[IOWOLF]

THANK YOU,I'll see what I can find.

[aboard_epsilon]

6 amps

That's what I let it take.
it wanted to take the needle off the dial {ampmeter} ...it's coming back to me... now.... i used a scalectrix type controler on it to stop it going off the dial.
ie lots of thin wire raped around a peice of hardboard..in spiral fashion......then position one of the wires up and down the card board till you get six amps and then it wont screw your charger up.
btw ...it makes a nice buzzzing noice.....like having an eletrical substation in your workshop. lol
all the best.mark

[This message has been edited by aboard_epsilon (edited 07-24-2005).]

[This message has been edited by aboard_epsilon (edited 07-24-2005).]