Do car de-sulfators actually work? If so why aren't they more popular?
Car battery repair with de-sulfator?
- Thread starter AnthonyH
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Car battery repair with de-sulfator?
I don't know about modern versions, but in the old days people used to put "desulphate" tablets into the cells of the batteries to "revitalise them".
Modern batteries first don't have tops that can come off to top up acid or distilled water like the old days, also modern batteries are built to a minimum spec. with just enough lead? surface area to do the job, so any aggressive disturbing of the plates would probably finish them off.
Modern battery chargers often have a "repair function" which does seem to bring back some cranking amperage at least according to the battery tester I have used.
Fifty odd years ago we used to turn a battery upside down and drain the acid and built up muck away , flush them with a hose to bring all the sediment out which used to collect at the bottom of battery and short them out. Then refill with fresh acid from a large glass carboy, charge the battery up and often recover them. None of which is going to happen these days
Modern batteries first don't have tops that can come off to top up acid or distilled water like the old days, also modern batteries are built to a minimum spec. with just enough lead? surface area to do the job, so any aggressive disturbing of the plates would probably finish them off.
Modern battery chargers often have a "repair function" which does seem to bring back some cranking amperage at least according to the battery tester I have used.
Fifty odd years ago we used to turn a battery upside down and drain the acid and built up muck away , flush them with a hose to bring all the sediment out which used to collect at the bottom of battery and short them out. Then refill with fresh acid from a large glass carboy, charge the battery up and often recover them. None of which is going to happen these days
OP
OP
I think i'll get one, it can't hurt can it? I mean the battery is sealed so i can't get the acid on myself
I can vaguely remember being able to open batteries many years ago, it wouldn't be that hard to repair these. But i understand how its not so good for the people to have acid in the home.
I can vaguely remember being able to open batteries many years ago, it wouldn't be that hard to repair these. But i understand how its not so good for the people to have acid in the home.
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Well the de-sulfator looks like its worked a treat. The battery was 0% health and 0% charge, and now is 90% health and 90% charge, i'm trying to squeeze it out to 100% healthy and it can go back on the car. I can't see any reason the battery will somehow fail early, but only time will tell.
Its d-day for my first and maybe last ever clutch change tomorrow, all the car needs now is to put this battery on, tighten up the road wheels and cross my fingers....
Its d-day for my first and maybe last ever clutch change tomorrow, all the car needs now is to put this battery on, tighten up the road wheels and cross my fingers....
The Battery Minder has a good chance of helping. It can take a week to a month according to the manufacturer. I am guessing but assume some batteries are good candidates and some are not.
I put the Battery Minder (I think I have 5 now) on batteries not used in the winter and hope/assume it helps some.
I put the Battery Minder (I think I have 5 now) on batteries not used in the winter and hope/assume it helps some.
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I've just had a look at the battery minder, it looks good. Its an intelligent mix of trickle, desulfate and charge.
I've been testing the desulfator on an older battery. It was at about 30% health when i took it off the car permanently, while stored in the conservatory it went down to 10% health, but the desulfator hasn't been able to do anything with it. Its health is still at 10%. I guess the desulfator only works well with batteries that have only recently been discharged.
I've been testing the desulfator on an older battery. It was at about 30% health when i took it off the car permanently, while stored in the conservatory it went down to 10% health, but the desulfator hasn't been able to do anything with it. Its health is still at 10%. I guess the desulfator only works well with batteries that have only recently been discharged.
Ailing lead acid batteries are a problem we all come across if we mess about with cars. At college we had a "proper" battery room and we managed to rescue a number of batteries by doing what Mike describes - draining and flushing the battery before refilling with fresh acid solution. Non of the garages I worked in had such a facility and I've come across several DIY methods of, supposedly, reconditioning a failing battery. I remember commercially sold tablets which you put in the cells and even alka seltzer tablets. These "cures" are all aimed at overcoming sulphation of the plates - which effectively stops the sulphated surfaces from reacting - but, one problem people don't realize is that very fine bits of the plates settle as a dust in the bottom of the cells and if this detritus builds up enough to touch the bottom of the plates then the battery will discharge while dormant.
I think trying to resurrect failing batteries is a bit like welding patches onto very rusted exhaust systems. Sometimes it works but often fails again soon after the repair. Definitely checking whether the charging system is working as it should - and remember a "smart" charging system may not give the same readings at the battery posts as the 13.5 to 14.5 you expect to see on an older vehicle - The long term cure is nearly always a new battery (and if you've got a more modern vehicle, especially with stop start, it's very likely the new battery will need to be coded to the electronics or it will fail prematurely. Exhaust systems? when they rust I just replace the affected part now.
Gosh, I just spotted the tablets on the Halfords website: Granville Bat-Aid tablets, and they seem to be still supplied in the tube as I remember it all those years ago, I think I still have an opened tube of them somewhere which I bought all those years ago. I believe they work by loosening/dissolving the surface layer of sulphation on the plate thus exposing fresh plate material to the electrolyte. It probably works too, but, if it loosens much of the inactive layer of sulphation it only has one place to go, which is the bottom of the cell and I've already mentioned above why that can be a problem. Cheap enough though so probably worth a try for a short term improvement until you can afford a new battery?
this is very much my view as well.
as you say there can be a build up of junk in the bottom of the batteries which can in some cases be quite literally the plates breaking down and falling apart.
Sulfation can also warp and distort the plates and the material plates are made out of are often porous to allow the electrolyte to permeate them and increase the contact area, so while you may be able to break down some of the sulfation that occurs this can go more deeply into the plate which can be near impossible to remove
the act of desulfation may therefore bring the voltages back up and on the face of it appear to show a "good" battery. But high loads may still drop the voltage too much and as some sulfation is still likely to be present it quickly builds back up again.
So as you say you can possibly extend the life of the battery but its unlikely you'll get "years" out of it.
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I think the problem is that most new batteries are sealed so you can't add battery acid tablets. Is it possible to buy non-sealed batteries?
I can just about remember non-sealed car batteries (i think), but never tried to repair them.
Rare to see a battery with caps on the cells these days, especially for cars. Anyway, the electrolyte is constituted differently for modern sealed batteries to reduce gassing for the very reason that you can't top them up - Have you noticed how difficult it is to even find distilled water these days? Because of this difference in what's in the electrolyte, even if you prize off the top of the battery, you're not going to be able to obtain top up fluid. If I was cynical, I'd say it's all a plot to sell more batteries? but that would be ridiculous wouldn't it?
I was interested by comments made by a chap who works in one of the large, off site, airport car parks - not someone I know, he was just part of a group of people chatting. Apparently jump starting cars which have been parked up for folks two week annual holiday is very common now, whereas a few years ago most vehicles would happily survive a fortnight without being run. He thought it was a combination of higher parasitic drain due to electronic systems not going fully dormant (anti theft etc) and the tendency for manufacturers to fit quite small batteries in modern cars which, of course, are now tending to have smaller engines so can "get by" with batteries of a lesser capacity - one litre being very common whereas not so long ago a 1500, 1600 1800 and 2000 cc were common family car engine sizes.
Edit. Batteries with cells you can top up are still seen on some of the horticultural/agricultural stuff, but sealed are probably more common now.
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I'm not sure how strong the acid inside a car battery is? But i've been around enough acid to know that a lot of chemical reactions can take place with relatively safe acid strengths. I mean vinegar is quite acidic.
So i'm with you in that sealed batteries aren't for safety purposes. They're to sell more batteries. I wonder if there would ever be a law that says desulfators have to be built into a cars electronics?
I have a scar on my arm which is an indication of how acidic car battery acid is.
I wouldn't put it anywhere near bare skin.
In many cases these days with stop start batteries they are sealed very much because they're not serviceable. A quick look for a Yuasa battery quickly brings up batteries that, while they may not have the individual removable caps for each cell, they do have a block you can remove which has plugs into every cell so you can still top up many more batteries than you perhaps realise.
I wouldn't put it anywhere near bare skin.
In many cases these days with stop start batteries they are sealed very much because they're not serviceable. A quick look for a Yuasa battery quickly brings up batteries that, while they may not have the individual removable caps for each cell, they do have a block you can remove which has plugs into every cell so you can still top up many more batteries than you perhaps realise.
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I've not looked into it in any detail, i now understand it can burn skin!
I'll keep in mind that there are still batteries available for top up. Hopefully i won't need another battery for a good while, but it can be hard to predict.
I'm still on the look out for another car, if and when i get another its quite likely the battery will be weak, will see.
The acidity changes depending on the state of charge, the whole reason that you get “sulfation” is because of the chemical changes in the battery when the battery is charged and discharged.
You have a lead dioxide (PbO2) plate which when it reacts with the sulphuric acid (H2SO4) turns to lead sulphate on the plate (PbSO4) and water (H2O) when it is recharged the
Water and the lead sulphate react the other way with the plate Turing back into lead dioxide and the water turning back into sulphuric acid.
So the more you charge the battery the more acid becomes present.
As there is also a by product of release hydrogen from the charging process the water does go down over time, which results in a build up of sulphur on the plate and then there is less water for the sulphur to react with and so it build up on the plate and while you can add water back the balance of chemicals in an old battery still leads to sulphur and oxygen being trapped in the plate as PbSO4
You have a lead dioxide (PbO2) plate which when it reacts with the sulphuric acid (H2SO4) turns to lead sulphate on the plate (PbSO4) and water (H2O) when it is recharged the
Water and the lead sulphate react the other way with the plate Turing back into lead dioxide and the water turning back into sulphuric acid.
So the more you charge the battery the more acid becomes present.
As there is also a by product of release hydrogen from the charging process the water does go down over time, which results in a build up of sulphur on the plate and then there is less water for the sulphur to react with and so it build up on the plate and while you can add water back the balance of chemicals in an old battery still leads to sulphur and oxygen being trapped in the plate as PbSO4
Which all goes to demonstrate that the typical lead acid battery is degrading from the day it's filled with electrolyte. This process can be greatly affected by how you use the battery. Used to be that one of the major things was loss of electrolyte due to the water being turned into gas (hydrogen and oxygen) which was easily rectified by topping up with distilled water - the acid content doesn't alter - and keeping the battery in a good state of charge. Now a days you can't really top them up so just checking their state of charge periodically and putting them on a smart charger if you don't use the car very much can pay dividends. I check standing voltage every time I do my level checks and hook up the smart charger if/when voltage heads south of about 12.5 volts. I'd also recommend applying a battery terminal protector (some call it grease but the best products are specifically formulated for the job. I have a tube of No-corrode which has lasted me for years and I see Granville and Liqui mily products advertised) Also keeping the battery clean should be a priority, especially the top of it, as current can drain through the dirt on a dirty battery.
