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Posted by Piccolo Pete on July 5, 2008, 4:12 pm
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> Piccolo Pete wrote:
>>
>>>
>>>
>>>
>>>>
>>>>> Piccolo Pete wrote:
>>>>>
>>> ====snip====
>>>
>>>
>>>>> I knew a guy who used to sell " reconditioned batteries", he used to
>>>>> swear
>>>>> that reversing the polarity when
>>>>> charging them was his secret ;`) I bought one off him and it lasted
>>>>> over a
>>>>> year before it died.
>>>>>
>>>> I'm not sure I would like to try that. But, I suppose free batteries
>>>> are
>>>> something to experiment with. Seems like it would make them explode,
>>>> though.
>>>>
>>> That's exactly the process used to form the plates on the very first
>>> commercially made lead acid rechargable wet cells. Pure lead plates were
>>> used for both electrodes only becoming an anode and a cathode by
>>> applying a charging current to form a porous red lead coating on the
>>> plate connected to the positive side of the charger with the negative
>>> remaining as pure lead.
>>>
>>> The initial capacity was quite low due to the negative allowing only a
>>> small part of the lead plate to interact with the electrolyte. By
>>> discharging and then reverse charging to convert the sulphated positive
>>> plate back to pure lead whilst forming a porous red lead coating on what
>>> was originally the negative plate, more of the lead was able to interact
>>> with the electrolyte and the capacity increased.
>>>
>>> The process was repeated several times until pretty well both plates
>>> had become sufficiently porous enough to approach a maximum practical
>>> capacity.
>>>
>>> Nowadays, the cathodes are manufactured in a seperate process which
>>> effectively creates a "dry charged" cell which, when filled with
>>> electrolyte, is in an already charged state. Unfortunately, the
>>> mechanical robustness of preformed anodes and cathodes is no match for
>>> the older electrically converted 'Plante' formed lead acid cell.
>>>
>>> --
>>> Regards, John.
>>>
>>> Please remove the "ohggcyht" before replying.
>>> The address has been munged to reject Spam-bots.
>>>
>>
>> So I'm not sure what you're saying here. Sounds like the really old
>> batteries could deal with their polarities being reversed but the new
>> ones can't. By the way, I already blew up one charger by accidently
>> reversing polarity. I don't want to blow another one.
>>
>> Bart
>>
>>
> If the battery is "dead", as in no charge, how can it blow up?
I didn't say the battery blew up in this post. I also didn't say the
battery was dead at the time. The battery in question was a good battery
that just needed to be recharged. I said the charger blew up. To be more
precise, I believe it was an electrolytic capacitor. They don't like
reverse current. Fun as electronic smoke bomb and fire crackers, but not so
fun when they are in a piece of electronic equipment.
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