Dead NICad solution

mawk

im not saying that this is a particularly great idea but its certainly interesting to see a welder used as nothing but a high current DC power supply

http://www.instructables.com/id/Revive-Nicad-Batteries-by-Zapping-with-a-Welder/

DublinDilbert

It is interesting, considering how many rechargeable batteries are discarded each day cause they will no longer take a charge....

I also saw a design for a resonance circuit, which will rejuvenate a car battery... It actually takes the power to/from the lead acid battery using a resonance circuit with some active elements. This process cleans the plates of the battery. Keep meaning to build and try it out some time...

Capt'n Midnight

I've seen mention that 30MHz is good for rejuventating lead acid

re NiCAD - replace them with NiMH , less toxic and double / trebble the life

if you don't have a welder you could use a large capacitor to zap the short circuit

DublinDilbert

The capacitor idea is a good one! And a lot safer too, only a limited amount of energy... You could make up a circuit with a relay to charge the cap from a voltage source, then discharge into the battery, and repeat say 10 times....

I didn't think it was as high as 300MHz, it would be hard to transfer a lot of power (high currents) at that frequency... I liked the idea of a resonance circuit which is powered by the battery that you just clip on. Imagine the amount of lead acid batteries thrown out each day just cause the plates are sulphated...

mawk

Capt'n Midnight wrote: »

I've seen mention that 30MHz is good for rejuventating lead acid

re NiCAD - replace them with NiMH , less toxic and double / trebble the life

if you don't have a welder you could use a large capacitor to zap the short circuit

yeah having read s'more i found another person made a NiCd zapper using a disposable camera. pretty much the same gig that thats been used for stun guns, coil guns, tesla trees... all that jazz

derry

If you need this to sort the Nicads out you were using the wrong charger in the first place .

I have used for many years many different types of battery packs from nicads to NIMH to Lithium polyimer and lead acid types in my hobby as electric model planes and helicopters

We Use superiour chargers made to charge and discharge and balance these cells .
Our charger stop denderite forming in the first place so we dont get these issues with nicads.However the biggest killer of Nicads is leaving them dischage over time in the cuboard or tool box.Our chargers have cycles that revive most all nicads from this problem
I get all my packs and chargers from
www.greenhobbymodel.com

These guys would be for me in the ROI the leading electric battery suppliers and experts

Sulpahetion on lead acid plates if it is light can succeed .If the sulfation layer is thick it falls of the plate and falls down between the plates and often shorts out the plates.Also it requires much larger power to de-sulphate the thicker layers and this type of power often can melt the battery.Its not for the amateur .Lead acid batteries give off Hydrogen gasses when stressed which can explode coupled with strong acid makes a nasty accident for unproteced skin

Applying the welder to NiCads or appling too much of the wrong power to NIcad can cause it to explode violently

Some Nicads can be saved from properly done Zapping.
Usualy those that were early in the cycle life such as 300 cycles and badly treated .Nicads can do as much as 1000 cycles . No amount of zapping will generally make a 1000 cycle nicad revive .

Nicads are now not availble in EU or ROI for sale due to toxic qualities

NIMh is not so robust as NiCads and have less cycle life often less than 600 cycles .They have bigger capacity so things like drill runs longer .

Lithuim polymer is fragile but runs for longer times with higher capasity but low cycle life between ~20 to ~500 cycles depending on Quality.Primitive Zappers will kill them dead and possibly make them explode violently and create a large fire ball

https://www.youtube.com/watch?v=WeWq6rWzChw

Lithuim ferros titanate can take a lot of abuse and return cycle life of between 1000 to 2000 cycles .No demand much for zapping these cells if using a good charger with balancer features .
However power density isn't great compared to lithuim polymers


Derry

cabbott

been doing a bit of reading about this over the last few days, i zaped a 12v black and decker battery with a 18v ryobi battery, the b+d was only putting 7v fully charged, but after zapping was putting out 13.5v, i charged the battery and it now has loads of power. could have saved myself €65 by not buying the ryobi drill and just fixed the b+d battery if id found out about this trick earlier.

mawk

using a new battery to fix an old one aint a bad idea.

isn't learning tricks fun!

DublinDilbert

cabbott wrote: »

been doing a bit of reading about this over the last few days, i zaped a 12v black and decker battery with a 18v ryobi battery, the b+d was only putting 7v fully charged, but after zapping was putting out 13.5v, i charged the battery and it now has loads of power. could have saved myself €65 by not buying the ryobi drill and just fixed the b+d battery if id found out about this trick earlier.

It would be interesting to see how it performs over the next while and if its fully rejuvenated...

Although €65 for a 18V roybi is very sweet... I would love to buy one, but my 10 year old bosch drill just keeps going and going!

bingus666

mawk wrote: »

using a new battery to fix an old one aint a bad idea.

isn't learning tricks fun!

please explain more! I have old B&D 12v batt - wont recharge in charger so bought a new batt - it fine. How do i "zap" without electocuting myself in the process? which would not be good....

cabbott

you wont electocute yourself its all low voltage stuff, just put + to + and - to - for a few secs simple as.:)

bingus666

okay but it doesnt indicate which is which on the battery! as in + & - terminals

FarmerGreen

If it its the same type of battery then its left to left and right to right.

cabbott

just put a multimeter accross it if you get a - reading the red probe is connected to the -.

bingus666

nice one! last question, if I use a fully charged car jump starter would that be ok? neither will explode? cheers

FarmerGreen

Just dont attempt it.
The trick is to use a huge amount of current to vaporise short circuits within the cell.
I flashed my drill battery across the one in my car, backwards
With a welders glove and face protection.
It got rather hot so I chucked it.
Risky, I'd say.

cabbott

you put in 1.5 to 2 times the power of the battery you are zapping. 12v is 18 to 24v.

paddy_joe

i have a 24volt bosch drill with 3 dead batterys,what can i use to revive these? hpw long will they last then?

pat

mawk

Depends on the type of battery. Nicad, nimh, lion..

You can use a 36v-ish bench power supply, welder, big capacitor, or maybe three car batteries in series. Hell, you could even try putting the two spare batteries in series and zapping the third. Might not work but costs you nothing to try

mfceiling

Hi lads,

I've an 18v hilti battery which stopped taking the charge a while back.
I put it on the charger and hit the refresh button which is supposed to re-set the battery's memory and start it from scratch but to no avail.
Could anyone fix it fo me in dublin (i'll gladly pay).
Rather not give 60 or 70 quid for another one.
Thanks.

derry

Dead thread reopened warning

@mfceiling
The only place I know that can offer a service like that is Green Hobbies in Dublin.
www.greenhobbymodel.com
Because model planes use really complex batteries including lipo they have special chargers that might revive the pack

goodluck

Derry