[EE] Desulphating batteries with Epsom salts

[ivp]

Has anyone here tried this ?

www.homepages.ihug.co.nz/~pcaffell/Battery_Maintanence_Tips.pdf

New to me but apparently been around for a while. The various articles
I've seen have never mentioned chemical desulphation

Joe
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[John Gardner]

Your link does'nt respond, but there are several
chemical schemes I've heard of, but not tried...

Take a look at this:

http://faq.f650.com/FAQs/BatteryFAQ.htm#EDTA

Home Power magazine's site used to have lots of
interesting lead-acid lore, but they've changed their
format (again) & a casual search did'nt turn it up.

Experience says it's likely still there; just better hidden.
Go figure.

Jack

[Roger, in Bangkok]

Try http://homepages.ihug.co.nz/~pcaffell/Battery_Maintanence_Tips.pdf for
the OP link.

RiB

[John Gardner]

Interesting stuff, RiB - Thanks.

Joe - Per the last discussion of lead-acid lore,
I'm 8 months in now on a 24V 33AH gel cell battery,
bought new for a scooter, charged with the scooter's
built-in charger for a month, then switched to:

http://www.navstore.com/detail.aspx?ID=1712

Average use is 1-2 miles/day, with a weekly 5 miler,
occasionally two...

These jaunts involve significant grades, though. The
5 miler has a 700 ft elevation gain, measured by GPS.
Most of that change is a ~ 1 mile hill - A good pull.

Once, so far, I've put enough demand on the battery
to notice performance fall-off - A hilly ten-mile run.

So far the battery performs as new - We'll see what
happens when the hot weather gets here, soon.

[ivp]

> http://www.navstore.com/detail.aspx?ID=1712

Certainly not a transformer and a diode !!! More like NASA specs

[John Gardner]

> More like NASA specs

Yeah - So far I'm pleased.The scooter's built-in charger is designed
to keep the battery store happy, not me.

[John Gardner]

Meant to mention - If you try any of the chemical fixes
out there I'd be interested to hear about results...

thanks, Jack

[ivp]

> Meant to mention - If you try any of the chemical fixes
> out there I'd be interested to hear about results...

I've not tried adding Epsom salts myself but the person who told
me about it reports a new lease of life on his battery. I can imagine
how a chemical reversal might be effective, assuming that chemicals
can get to places where regenerating pulses wouldn't, if they take
only paths of least resistance for example

[Sean Breheny]

I think that the chemical fixes really only apply to flooded lead acid
batteries (i.e., the kind where you can add water), not sealed ones. I
think you said, Jack, that your battery is a gel cell type, which
would be sealed as far as I know.

Sean

[John Gardner]

Yes, that's correct, for the batteries I mentioned.
Gel cells have the virtue of very low impedance,
which is good for wheelchair apps. The tradeoff
is fewer charge/discharge cycles - All the more
reason to take good care of them.

Most large deep-cycle batteries are flooded-cell;
Trojans, for instance, which will deliver very long
service life, properly sized to application & main-
tained...

[Michael Rigby-Jones]

> -----Original Message-----
> From: piclist...@mit.edu [mailto:piclist...@mit.edu] On
Behalf
> Of John Gardner
> Sent: 11 June 2010 02:03
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] Desulphating batteries with Epsom salts
>
> Yes, that's correct, for the batteries I mentioned.
> Gel cells have the virtue of very low impedance,
> which is good for wheelchair apps. The tradeoff
> is fewer charge/discharge cycles - All the more
> reason to take good care of them.

AFAIK gel cells typically have a *higher* internal resistance than
flooded lead acid cells due to decreased ion mobility in the
electrolyte. Absorbed Glass Matt cells (often confused with gel as both
are sealed) have equivalent or sometimes lower internal resistance.

Regards

Mike

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[Michael Watterson]

Michael Rigby-Jones wrote:
>
>> -----Original Message-----
>> From: piclist...@mit.edu [mailto:piclist...@mit.edu] On
>>
> Behalf
>
>> Of John Gardner
>> Sent: 11 June 2010 02:03
>> To: Microcontroller discussion list - Public.
>> Subject: Re: [EE] Desulphating batteries with Epsom salts
>>
>> Yes, that's correct, for the batteries I mentioned.
>> Gel cells have the virtue of very low impedance,
>> which is good for wheelchair apps. The tradeoff
>> is fewer charge/discharge cycles - All the more
>> reason to take good care of them.
>>
>
> AFAIK gel cells typically have a *higher* internal resistance than
> flooded lead acid cells due to decreased ion mobility in the
> electrolyte. Absorbed Glass Matt cells (often confused with gel as both
> are sealed) have equivalent or sometimes lower internal resistance.
>
>

That's my experience too, in real life and datasheet.
Also gel cells more easily destroyed or short life from
* Overheating (Charge, discharge or Ambient electronics in same box)
* Leaving near discharged
* Deep discharge.

Using same AH gel as replacement for "wet" battery in a Motorcycle will
last only a few weeks as the starter motor stall/startup current is too
high.
There are some gel cells specially designed (or maybe just marketed) for
higher peak currents.

[John Gardner]

Thanks for correcting my error, Mike. The battery I'm
talking about is indeed AGM, not a GEL cell.

Optima AGM datasheets claim an internal impedance of
2 milliohms.

Datasheets of flooded-cell batteries with similar AH ratings
claim Z = 10 milliohm. Quite a difference.

Quite a diffference in price, too, it should be said :) Horses
for courses...

best regards, Jack

[Bob Blick]

On Fri, 11 Jun 2010 06:37:36 -0700, "John Gardner" said:
> Thanks for correcting my error, Mike. The battery I'm
> talking about is indeed AGM, not a GEL cell.
>
> Optima AGM datasheets claim an internal impedance of
> 2 milliohms.
>
> Datasheets of flooded-cell batteries with similar AH ratings
> claim Z = 10 milliohm. Quite a difference.
>
> Quite a diffference in price, too, it should be said :) Horses
> for courses...
>

I have a non-Optima AGM battery in my car:
http://www.batterymart.com/p-12v-mazda-miata-battery.html

Just a gut feeling but I don't think it has as low an impedance as a wet
battery. When I bought the car it had a regular battery in it and it
seemed to crank faster than with the AGM.

So maybe the Optima "fruit roll" process is superior to how mine is
constructed.

Cheerful regards,

Bob

--
http://www.fastmail.fm - Send your email first class

[John Gardner]

I have the impression there are AGMs, & then
there are AGMs...

If you have an Optima battery you probably know it.
They are *quite* expensive - As in double what the
PowerSonic batteries in my scooter cost - Which
I'n not unhappy with.

This engineer is a big fan of Optima AGMs...

http://www.wheelchairdriver.com/powerchair-batteries.htm

Jack