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gordon stephenson
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Don't know about Epsom salts but way back in the 60s all car shops sold a packet of white tablets, one to be dropped into each cell.Don't know if they worked or not.
madkayaker
Pro sparkey Pro Welder
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I got some stuff for sorting a big tractor battery but never got around to using it but its supposed to work well. In my case I just left the charger on for a couple of days and fixed the charging regulator and away the tractor went
Wendelspanswick
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Best way is to stick 36-48v through the battery to knock the sulphur off the plates, I tend to use a couple of decent batteries and a battery charger in series and wire this in parallel to the knackered battery till it freely gasses, normally about 5 minutes, rest for 10 minutes and repeat till the battery holds a decent voltage.
Used this technique to rescue lots of supposedly dead batteries.
Used this technique to rescue lots of supposedly dead batteries.
pedrobedro
Man at Matalan
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My charger has a desulphate cycle which worked on a knackered battery I had in the shed for a few months. It cycles a high voltage through the battery till it takes a charge.
Shox Dr
Chief Engineer to Carlos Fandango
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What ever method you use remember the risk of explosion. Good ventilation and every thing switched off before unhooking!
And not forgetting, to vent the battery
Yes, about a quarter teaspoonful in each cell. It got a bit more life out of the battery til I could get a new one. I read that it just drops the resistance of the battery acid, or what's left of it. Another cure is half an aspirin in each cell.
I've also also seen electronic gizmos for rejuvenating batteries which someone mentioned previously. I don't know whether they work or not. There have always been potions to fix batteries.
I'm inclined to think that a knackered battery is a knackered battery and if it's a battery on a vintage car which doesn't get that much use, the only way to stop it being knackered through self discharge and sulphating, is to leave it on a float charger.
Shox Dr
Chief Engineer to Carlos Fandango
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^^Agreed
Case in point I and a mate both had the same bikes, model yr etc. Even down to how much we used them.
I had an Opitmate connected as soon as it went back it the lockup. He didn't use anything.
In the 8 yrs we owned them, I never replaced the battery nor had any problem. He on the other hand he went through at least 4 batteries that I know of, and none of them were cheap either
Case in point I and a mate both had the same bikes, model yr etc. Even down to how much we used them.
I had an Opitmate connected as soon as it went back it the lockup. He didn't use anything.
In the 8 yrs we owned them, I never replaced the battery nor had any problem. He on the other hand he went through at least 4 batteries that I know of, and none of them were cheap either
MattF
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Pretty much sums it up. You can generally get some life back in one with sulphated plates, (which as has been mentioning, charging them with a higher voltage for a while usually works), but it'll ne'er be at full capacity again, and will just keep getting worse. It's a temporary measure at best, useless at worst.
Cobbler
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I tried the white tablets years ago on a battery that would not hold a decent charge, they did absolutely nothing, in fact from what I remember it died even quicker. I don't know what is in the tablets, but not used them since.
Cobbler
Cobbler
Leisure batteries are different to car batteries. They can't give the cranking current, but they will tolerate deep discharge with moderate currents.
However, with all lead-acid batteries, if you leave them discharged, they start to sulphate up and you lose capacity, and they self discharge.
I don't see you've got much option but to charge it fully every time you use it and give it a top up every couple of weeks, or better still, leave it on one of the new chargers which goes to float charging, that is once it's charged, continually puts in a few milliamps to counter the self discharge.
However, with all lead-acid batteries, if you leave them discharged, they start to sulphate up and you lose capacity, and they self discharge.
I don't see you've got much option but to charge it fully every time you use it and give it a top up every couple of weeks, or better still, leave it on one of the new chargers which goes to float charging, that is once it's charged, continually puts in a few milliamps to counter the self discharge.
shenion
Tool Pack Rat
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I made float chargers and have one on my web site. There is also a linkt to Panasonics discussion of charging methods.
On my mower, I have the above circuit powered by a 9W solar cell. So, no power needed in the shed.
I have a few 12V power supplies I have adjusted to 13.2 volts that I use to keep batts from self-discharging.
Epsom salts and the cadmium tablets will eat away the outer layer of the lead plates. That gives a fresh un-sulfated surface that will work but the plates get thin and can break.
I have revived sealed batts by charging with 40V or more through a resistor. Whn a batt is fully discharged, all the acid moves into the plates leaving non-conductive water (pure water is an insulator.) So, it takes a higher voltage to get current to flow. once you get it to draw current, you might be able to revive them.
My Mustang batt sat for 9 years. It was completely open. Managed to get it to draw a little current. Several days on charger and it was good enough to get the solenoid to click. Drain and recharge and the starter would clunk. I charged and draine dit via the starter every day for a week or so and it got to the point I could start the car. Lasted 2 years from then.
On my mower, I have the above circuit powered by a 9W solar cell. So, no power needed in the shed.
I have a few 12V power supplies I have adjusted to 13.2 volts that I use to keep batts from self-discharging.
Epsom salts and the cadmium tablets will eat away the outer layer of the lead plates. That gives a fresh un-sulfated surface that will work but the plates get thin and can break.
I have revived sealed batts by charging with 40V or more through a resistor. Whn a batt is fully discharged, all the acid moves into the plates leaving non-conductive water (pure water is an insulator.) So, it takes a higher voltage to get current to flow. once you get it to draw current, you might be able to revive them.
My Mustang batt sat for 9 years. It was completely open. Managed to get it to draw a little current. Several days on charger and it was good enough to get the solenoid to click. Drain and recharge and the starter would clunk. I charged and draine dit via the starter every day for a week or so and it got to the point I could start the car. Lasted 2 years from then.
