[TechAssist] Re: Any way to revitalize dead sealed lead acid batteries?
- From: Edward Gaidies <teltek3@xxxxxxxxxxxx>
- To: techassist@xxxxxxxxxxxxx
- Date: Mon, 30 Aug 2004 22:06:23 -0400
Gary;
Are you sure they are Lead Acid?
Presuming that they are..."Shocking" and reverse polarity will not give
you a viable battery for resale.
Best thing I learned from this post, was the guy that tried to top
these batteries up in the Medical Field.
I think most of us have no idea what is required, even the
manufacturers don't know.
Watched a program on TV..two weeks ago, manufacturing batteries for
Vehicles.
I recorded most of them...
But I presume..if someone invented a "Battery" that only needed
recharging and no replacement, someone would soon be out of business.
Too bad we are "Fixers" and not "Inventors".
I will not go (OIL/INTERNAL COMBUSTION/GONE TO THE MOON AND BACK) and
we can't even get a decent battery to power our Digital Cameras.;-)
Damn..(sorry)..every time I think about it...Some big company decides
what we need.
They will give us Printers for under $30....next time you need a
Cartridge $42.95.
And now they have purposely installed a "CHIP" so you can not refill
them.
Do I need to expand? Probably not.
Ed Gaidies
Tel-Tek Electronics
Ontario-Canada
teltek3@xxxxxxxxxxxx
On 30-Aug-04, at 9:32 PM, Gary McCartney wrote:
> Jim, thanks for the suggestion. So far I have tried the reverse
> charging
> on one battery. Here is what my observations are:
>
> -initial battery read 4.1V and would not supply current to a load
> -reversed charged for several seconds but would not draw more than
> 100mA
> during this time.
> -then normal charged where it would only draw a few 100mA. Got up to
> 7.3V after a few hours and wouldn't supply current to load
> -reversed charged again and this time it drew around 200 mA
> - normal charging would now draw 100mA but still wouldn't supply much
> current to a load. A small lamp lit dimly for 5 minutes and went out.
> -repeating the reverse charge- normal charge cycles seems to allow more
> current to be drawn each time.
> - last I tried, I was able to draw over 1 amp reverse charge and 200 mA
> normal charge. Battery reads 9.4V after a few hours charge but won't
> supply much current. I will attempt this on another battery to see if
> it
> reacts the same as the first battery. I will also try to reverse charge
> for a longer time period, such as a full minute. Will post another
> update on the experiment.
>
>
>
>
> Gary McCartney
>
> McCartney Electronics
> Guelph Ontario Canada
> Est. 1984
> email: gary (at) number63.ca
>
>
>
>
>
>
>
> Jim Shupe wrote:
>> 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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