Post by thread:[EE] Desulphating batteries with Epsom salts

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

Try http://homepages.ihug.co.nz/~pcaffell/Battery_Maintanence_Tips.pdf for the OP link. RiB On Tue, Jun 8, 2010 at 23:31, John Gardner <spam_OUTgoflo3TakeThisOuTgmail.com> wrote: {Quote hidden}> 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 > -

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. Jack

> 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

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 On Thu, Jun 10, 2010 at 6:17 PM, John Gardner <.....goflo3KILLspam@spam@gmail.com> wrote: > Meant to mention - If you try any of the chemical fixes > out there I'd be interested to hear about results... > > thanks, Jack > -

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... Jack

> -----Original Message----- > From: piclist-bouncesKILLspammit.edu [.....piclist-bouncesKILLspam.....mit.edu] On Behalf {Quote hidden}> 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 ======================================================================= This e-mail is intended for the person it is addressed to only. The information contained in it may be confidential and/or protected by law. If you are not the intended recipient of this message, you must not make any use of this information, or copy or show it to any person. Please contact us immediately to tell us that you have received this e-mail, and return the original to us. Any use, forwarding, printing or copying of this message is strictly prohibited. No part of this message can be considered a request for goods or services. =======================================================================

Michael Rigby-Jones wrote: {Quote hidden}> >> -----Original Message----- >> From: EraseMEpiclist-bouncesspam_OUTTakeThisOuTmit.edu [piclist-bouncesspam_OUTmit.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.

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

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

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