high volts on reclaiming an OLD battery

[shadow44]

OK so yea I am new at this. Very new :-)

sg running smooth, so i dug out a small car battery. made in '03 not been in a car at least 5yr maybe more. not all swelled up. Thought I might try to reclaim it from the dead. tried to charge it about a month ago on a reg charger. Not happnin. So anyway hook it to my sg, it has 6.79v and the lights came on. so i check my voltage on the charge battery almost 17! Disconect So, should I get my football helmet out put it on, let it run, hope it dont detonate, or whats the procedure to get the voltage down?

[shadow44]

OK I got brave and am letting it run. it goes up to about 18v then seems to drop to the 15-16 range climbs drops. My assumption is its breaking down the sulfite or dendrites since its in such bad shape... OOps i better go check it make sure its not getting hot!

[shadow44]

Oh bugger! watch what you touch! I tried to touch the transistors to check their temp... after I got up I went and got the lazer thermometer! That little thing will shock the crap out of you! Go ahead and laugh at me, I am...

[John_Koorn]

OK I got brave and am letting it run. it goes up to about 18v then seems to drop to the 15-16 range climbs drops. My assumption is its breaking down the sulfite or dendrites since its in such bad shape... OOps i better go check it make sure its not getting hot!

Shadow, this is normal for a sulfated battery. The transistor temp should come down as the battery takes the charge.

John K.

[shadow44]

Shadow, this is normal for a sulfated battery. The transistor temp should come down as the battery takes the charge.

John K.

Well I let it run for about an hour on a half dead alum battery. replaced the input battery with a good full lead acid. bad plan. burnt a transistor. guess i got carried away, should have waited for the heat sink insulators. back running on 6 wires. well kinda, I jumped that coil wire to another transistor, but dident see much difference. probley too long of a jumper.

[aln]

Shadow, in my experience with desulfating batteries I have found that when the battery will not take a radiant charge, it has a short and if you keep trying to put a charge into it you will be buying new parts for your bedini circuit. Just my 2 cents. Al

[Faraday88]

Hi all,

I have a schematic (its like the Bedini-Cole bipolar switching) that will avoide this issue of 'keepbuying new Transistors'.
the schematic take care of the 'Radiant' accross a Battery that has 'shorted out plates in them while still not get hot and eventually burn out.
its a kind of serov mechanism of the circuit. I designed my Rejuvenator circuit this way.!
Rgds,
Fararady88.

[BobZilla]

*EDIT*
I just noticed this is an old thread but for anyone who is having the same issue with old batteries........


Shadow,
Just a little advise with that stubborn battery.

Go very small increments until it starts showing improvement. Charge it for only about 10 min, then pull a load with a small 12v auto lamp. It may only light up for a min or so but this is fine. Do it again short charge, short load, repeat.

It will not do you any good to keep it on longer, it will not start breaking down the build up until you get it to start shedding a little at a time. It behaves that way because there is practically no clean surface area on the plates. As soon as it starts heating it has taken all that it can for that cycle, pull it back down and do it again. After doing that quite a bit (like 30 times) it will start taking longer to charge and will run the bulb a bit longer, then you can start leaving it on a bit longer.

The point I am trying to make is just leaving it on the charger will not help, you have to pump it back into life a little at a time. I have recovered many batteries this way. And yes it will jump around a bit as you described. If you were to look at it on a charge chart you would think you were looking at a discharge curve insted of a charge curve. It will start high like 18v and drop back, then a few bumps back up and down, jagged looking. That is normal for this process. Try to run your input on low, I don't know what kind of machine your using but if you have a pot on it , run it low at first.

Also not to state the obvious but, make sure you keep it saturated. Sometimes you can get the battery back to good condition but other times you may get stuck with a shorted cell. You really will not know until you go though the process though. Once it starts taking decent charges get a flashlight and look down in each cell for bubbles. If one of them is not bubbling it will be a bad cell.

[aln]

agreed

Bobzilla is right, small increments work. Faraday88, would you kindly share the circuit you described, please. I would put it to good use Al

[Faraday88]

Hi Shadow44,
I'm not clear on some of your points:
1) are you saying your dead battery is reading 17V or is it the Drive Battery voltage (Primary Battery) ?
2) what is reading 6.79V
Typical Battery explosion is only posiable when you use the Cap dump mode.... so no Helmet required here

Rgds,
Faraday88.

[Faraday88]

Hi ,

Please follow the Self-Energiser schematic (window motor) for Rejuvenator application, involves PNP and NPN transistors.
you can use MJL21194 & MJL21193 for this.
Rgds,
Faraday88.

[VortexTurtle]

Faraday88 - are you saying that a setup with the bipolar sequential switching is best for rejuvenating batteries?