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Desulphators

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Posted by Dave on April 25, 2016, 10:31 pm
 
Has anyone done any work that proves how useful electronic
desulphators are (or not) for improving lead-acid battery performance?
Many folks seem to have opinions but who has done the research?

Posted by mike on April 26, 2016, 9:13 am
 
On 4/25/2016 3:31 PM, Dave wrote:

Lotsa people claim to have done the research.  People who sell 'em
say they work.  People who buy 'em say they don't.

If desulpahtors worked, you'd be able to buy one at WalMart for $0
and everybody would have anecdotal evidence that it worked for them.

I've personally prototyped some of the methods and found them to be
of zero value in desulphating my batteries.

Best method is to maintain your batteries so they don't sulphate in the
first place.

Posted by Jim Wilkins on April 26, 2016, 12:13 pm
 
This works for me:
http://batteryuniversity.com/learn/article/sulfation_and_how_to_prevent_it  
" If a battery is serviced early, reversible sulfation can often be  
corrected by applying an overcharge to an already fully charged  
battery in the form of a regulated current of about 200mA. The battery  
terminal voltage is allowed to rise to between 2.50 and 2.66V/cell (15  
and 16V on a 12V mono block) for about 24 hours."

Notice that is for flooded batteries with filler caps, NOT sealed AGM  
types that don't tolerate much overvoltage-induced gassing. I've had  
no luck restoring those, even by popping them open and adding water.

The problem is finding an adjustable voltage / current controller to  
do it, and acquiring the knowledge to use it safely and effectively.

I design and build my own electronics and use a homebrew LM317-type  
adjustable voltage regulator powered from my solar panels to maintain  
outdoor vehicle batteries, with this meter to show what's happening:
(Amazon.com product link shortened)

It presently has an LM350 to match the meter's current rating. An  
LM338 on a bigger heatsink would allow 5-7 Amps in the same circuit.

An adjustable current limit isn't really necessary, just set the  
voltage to force the current you want. As a good battery charges the  
current will taper down. If the battery is heavily sulfated it might  
accept less than 100mA at >16V at first, then as it desulfates the  
current may rise. The LM317 will limit it to about an Amp.

I haven't tried pulse desulfators because the DC current method has  
added several years to the life of 'dead' U1 lawn tractor batteries  
people give me. The battery in my truck is from 2002 and still starts  
it. I top it off to 14.4 - 14.8V every month or so.

--jsw





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