[TechAssist] Re: Any way to revitalize dead sealed lead acid batteries?
- From: "J Silverman" <greentron@xxxxxxx>
- To: <techassist@xxxxxxxxxxxxx>
- Date: Mon, 30 Aug 2004 11:50:07 -0400
Thanks for the tip. I have a big box full of lead-acid camcorder and medical
equipment batteries that I have not yet turned in for recycling. We have
never had any luck restoring these. Most wont draw any current from a
charger, forward or reverse. If I leave one on charge for a long time, like
a few days, it may start to draw a continuous, small current. But it just
eventually gets warm and if I remove it from charge and put a load on it the
voltage drops to almost nothing. I guess there is no hope for those but,
aside from the sulfating problem, I always wondered what else was going on
inside.
Jerry Silverman
Greentron Inc
4 Newland Ave
Greenville SC 29609
Fax/Phone 864 232 3889
mail to: greentron@xxxxxxx
----- Original Message -----
From: "Jim Shupe" <jim@xxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, August 30, 2004 8:58 AM
Subject: [TechAssist] Re: Any way to revitalize dead sealed lead acid
batteries?
> Gary...
>
> Try reverse-charging (limit current to an amp or
> less) for a few seconds to a minute to get things
> going, then forward-charge at no more than 14.75V
> until the current drops below about 100ma. If this
> restores some charge to the battery, put it through
> several normal charge-discharge cycles to achieve the
> best capacity for THIS particular battery(I assign
> batteries a "personality", unique to each one's
> "experiences").
> If not much happens the first time, repeat several
> times before giving up. In my experience, it depends a
> lot on the brand and storage conditions(the cooler the
> better).
> I used to manage storage, maintenance and testing of
> gel-cell batteries as a test engineer for a medical
> equipment manufacturer, so I experimented with and
> researched a lot of this stuff.
>
> Batteries are still a long way from a reliable
> device. BTW...somewhere I have a schematic for a very
> good, simple two-stage gel-cell charger if you need
> one.
>
> Jim Shupe, CET
> Lloyd's TV
> Yucca Valley, CA
>
> --- Gary McCartney <gary@xxxxxxxxxxx> wrote:
>
> > I found a box of 10 brand new sealed lead acid
> > batteries, 12V 4AH that I
> > forgot I had. Problem is, they are all very low or
> > dead. I tried
> > connecting my power supply with current limiting but
> > the batteries
> > aren't drawing any current at all.
> >
> > Is there any way to kick these into charging up, or
> > are they garbage?
> > --
> >
> >
> >
> >
> > Gary McCartney
> >
> > McCartney Electronics
> > Guelph Ontario Canada
> > Est. 1984
> > email: gary (at) number63.ca
> >
> >
> >
> >
> >
> >
> >
> >
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