NiCad stuff

[PlayboyJoeShmoe]

I read on some thread about "shocking" NiCads back to life.

I had a second Stinger battery stick show 1.3ish V and wouldn't take a charge.

I had an idea and took a wire with two alligator clips and a 12V battery. I hit the positive with the wire and held the bottom of the stick to neg.

I held it until the stick got warm.

Initial reading after doing it was 3.63

Back in the light and on charger for a couple hours, I pulled the stick and read 4.12V.

Perhaps all it needed was a jump start?

Anyhow I did the other stick and held it until quite warm. Initial reading 3.93

Stinger is on a charge cycle of 8 on, 16 off.

Will see what there is to see on monday.

 

[Kevin Tan]

Have a MagCharger batt that will lose charge in 1 day. What do u suggest?

 

[Curious_character]

I read on some thread about "shocking" NiCads back to life.

I had a second Stinger battery stick show 1.3ish V and wouldn't take a charge.

I had an idea and took a wire with two alligator clips and a 12V battery. I hit the positive with the wire and held the bottom of the stick to neg.

I held it until the stick got warm.

Initial reading after doing it was 3.63

Back in the light and on charger for a couple hours, I pulled the stick and read 4.12V.

Perhaps all it needed was a jump start?

Anyhow I did the other stick and held it until quite warm. Initial reading 3.93

Stinger is on a charge cycle of 8 on, 16 off.

Will see what there is to see on monday.

You've encountered a fairly common problem with NiCd cells -- they grew metal dendrites which shorted the cells. And you've discovered that you can vaporize the dendrites by zapping them with a very high current, which is a common cure that often works. It's safer, though, to charge a big capacitor and use that for the zapping. Unfortunately, zapped cells tend to have a high self discharge rate, and they readily grow dendrites again. So the cells are nowhere near as good as new. You should be able to find a great deal of information about this on the web.

c_c

 

[Curious_character]

Have a MagCharger batt that will lose charge in 1 day. What do u suggest?

Replace it.

Kinda reminds me of the Wizard of Id cartoon which was pasted to our bathroom mirror for many years: Wiz's wife Blanch to hairdresser: "I'm going to the royal ball tonight, Pierre, and I want to be the most beautiful woman there. What do you suggest?" Pierre: "Reincarnation."

c_c

 

[PlayboyJoeShmoe]

I got nothing to lose, even if runtime is short. Because as it was each stick would only get the bulb to glow faintly. As of Friday at about 4:30 PM it was as bright as it had ever been.

So it's not useless like it was.

That M*gcharger battery might be better with a zap. But I would not bet on it. I took a dead MC stick apart and found a few of the cells that were in fact dead. I even tried zapping back then and it didn't help.

My theory is the Stinger charger didn't know what to do with 1.3ish V. But once I zapped, it takes over.

 

[yellow]

somehow I think, using such a "high" voltage batt with a completely dead one, equals to a shortcut...
If the charger does not start because of undervoltage, just hook a "good" battery in parallel and the charger should start, then remove the other batt.

as to "revive" the old batt stick:
there is this site: http://www.wildflyer.de/ unfortunately in german ...
in short he connected every cell with a diode in series with a 5 ohms resistor.
The resistor discharges the cell and the diode ensures that the voltage does not go under 0.6-0.7 Volts (which is about a still safe value for NiCads/NiMhs).
Thanks to the slow dischage of every cell the crystals should disappear within some use and he had some old-and-bad batteries revived to original value.

I did this with older P90 sticks and it also worked for me. As I dont want to loose 100 mA per hour, I used way larger resistors (100 Ohms and such).

If there is enough space inside the body, trying the method better than throwing the batt away ...

 

[PlayboyJoeShmoe]

Update: The stick I did first and put in the Stinger is holding a charge that lets the light run for a while even in the afternoon after the timer stopped at 8AM.

The second stick went right back to 1.3V in a couple days.

I saved the ground gadget and the one good sub-c from that pack and plan to have a nimh pack built.