I don't know if I dreamed this or saw it mentioned elsewhere - rebuilding a battery. In addition to my personal Ford fleet, I have an old MG that uses two 6 volt batteries in series to make a 12 volt system. (This was the original factory design, not mine.) The batteries are of a peculiar British size and shape to fit the rear compartments and needless to say, are quite expensive to replace - over $100.00 each plus shipping. A rebuilt battery seems the logical conclusion. I would appreciate comments and opinions of anyone here who has ever had a battery rebuilt.

 

Not those kind of batteries though some are like electric fork lift batteries. On you MG, you might tray a Tractor Supply or the like as they carry several styles of 6 volt batteries for older tractors and maybe one will work for you.

 

Batteries can by recycled, or reconditioned, but usually cannot be rebuilt because of the way they are constructed makes that practically impossible. However, there are a few things to do with "bad" batteries. If it's sulfated, just put on a low amperage charger (1 - 2 Amp) for a couple of weeks (check acid level occasionally) and hope that eventually the sulfate will get converted. You also need to make sure that the acid is of aproper gravity -- over time they tend to get diluted. There are fancy chargers that do pulsing and some other weird stuff, but you can usually get by without them. Another failure is the sediment at the bottom shorting out cells. That's more difficult to fix, but still doable. First, drain the acid carefully, with as little disturbance as possible. (you can usually save the acid as disposal might be a bit of a hassle) Put in distilled water, seal the holes, and shake the battery to loosen up the sediment. Drain water quickly before the sediment settles down again. Repeat this until most of the sediment is gone from the battery. Put acid back back (usually you need to add some extra acid to get the right gravity) and start charging. The battery will have less capacity then new, but that's expected.

Notes:
a) the sulphuric acid in the battery is fairly diluted so it's not as bad as the concentrated stuff, but it gets into your eyes, it can do some bad things.
b) the sediment contains lead and some lead compounds (mostly sulfate) -- they are toxic, so dispose then properly. Luckily, they are usually heavy and not particularly water soluble.

 

As a kid I used to pass a shop were the man rebuilt batteries. You have to remember thiswas right after WW2. At that time the tops were covered with tar. He would dig that out melt the cell connectors and replace the bad cells, by the way these were 6 volt batteries. With the contruction of todays batteries it would not be so easy. Trade in the old and buy a coulpe of new. Why not find a twelve volt that fit tha box and use it?

 

Appreciate the replies. I had heard of the slow/low amp reversal of sulfunated batteries and tried that for one month. It didn't seem to improve things at all and merely grew several large acid mushrooms on the positive post. I think I'll give the drain and flush routine a try - nothing to lose at this point.

 

If the battery measures 6V, but can't hold enough charge, then it's either badly sulfated, or lost capacity because the porous material fell to the bottom. If the battery measure 4, 2, or close to 0V, and won't go further, then you have some shorted cells, and that's when you try to get sediment out since most of the time that's what shorting the battery.

Batteries can also be shorted by deformed plates, or bridges between the plates -- there's not much you can do with deformed or bent plates, but smaller bridges can be blown with enough amperage, although that can also blow up the whole battery , creating a big and poisonous mess.

 

Your batteries are a group 17HF. New Castle battery in PA has them availableI believe they are dry so they can be UPS'd.Somewhere around $50 ea

 

Even if you did find someone to repair the batteries you have, or found a procedure to do it yourself, I bet it would be over $100.00 in parts and/or labor per battery to fix them.

 

You might want to check with Deka battery in Lyons, Pa. They are a manufacturer
and sell batteries with case imperfections at reduced prices. They are a
close competitor of Johnson Controls who I guess is the largest of all the
battery makers

 

Thanks for the information. These current failing batteries were a special order from Lucas of England, the original supplier. Just for authenticity, I hoping to be able to preserve these batteries. (At least the outer embossed case.) The maddening aspect is the batteries are not that old and the car is seldom driven. Even when disconnected, they don't seem to last very long. If the suggested flush routine does not revive them, I'll give New Castle a call.

 

your car uses 17F also used in tractors. napa sells them 45.00 each.

 

Sounds like they are sulphated. After you have tried your last hope, you can try this. Hold the battery a couple of inches off the floor and drop it a couple of times. It's a possiblity you could knock the sulphation loose off the plates and revive them. If you get a new set, get a battery tender of some sort to keep a trickle charge on them. If you do not have any electricity where you store the car, take the batteries out and keep them on a trickle charge at home.

 

You cannot knock sulfation loose off the plates.

There is actually a float charger (can be had for $8 and up) that can be used to keep the battery in good condition, but a trickle charger will work, too.

 

aurgathor,
Thanks for all the good information. Enlighten me, what's the difference between a float charger and trickle? I've been using a 3amp trickle charger trying to reverse the sulfated batteries. Float charger is a new one on me.

 

The trickle charger is just a low current charger without any sophisticated electronics. Float charger is very much like a trickle charger, except when the battery voltage reaches a certain point it will reduce the current more than a trickle charger, so it will not boil off the electrolyte over time. Some also have a temperature sensor in there to help to adjust the cutoff point more precisely.

Harbor Freight carries the cheapest one, that's about $8 on sale, but I've seen them go for as much as $50 -- I assume for that much you got a bit more sophisticated charger. A trickle or float charger won't do squat with a badly sulfated battery -- they usually need higher voltage to break down the sulfate layer (that's where the pulsating charger comes into play).

What voltage and amperage you have when the battery is being charged?