Lucas control box problem?

In message , The Natural Philosopher writes

Yup :-( I think the final test will be to remove the battery from the car after a run, then leave it for at least 24 hours, refit and try.

that or fix it. Self discharge can be caused by shed lead accumulating at the bottom of the cells. Tip acid out, rinse repeatedly with distilled water, return acid. Obviously the acid can eat you so various cautions apply.

Did that long ago & the battery lasted years.

NT

That all sounds a little scary! Straying into chain saw and angle grinder territory :-)

Meanwhile, been for a good run (25 miles), and now disconnected the earth lead. Will leave for minimum 24 hours, then try starting, and if battery not up to the job, I'll know for sure.

And pointless. Once car batteries won't hold a charge, they're scrap. Usually caused by allowing them to go completely flat.

IIRC batteries can develop plate -to - plate 'whiskers' which short it internally

Apocryphal tales of banging mega amps through to get rid of em.

BUt frankly a battery is not that expensive and for daily motoring why take the risk?

Get a new one

I've got a very posh ACT battery tester. It gives you an instant readout of the battery's actual capacity in amp.hr. Left over from when I was working. I'd expect any decent battery place to have similar.

Basically, if that capacity is something like 20% (or more) less than the figure on the case, it's scrap.

I hear figures like that often. I've run car batteries to way lower than that before they became problematic. I doubt the last one had 10% of its capacity left before it began to struggle.

NT

It does depend on the type of failure. I've had some which were OK one day, and dead the next. And how much 'reserve' the battery has which is going to depend on the individual make.

But this tester does show if your battery is good too. Plenty fit a new battery when the fault is elsewhere.

So like all test gear you do nee to know how to interpret the results.

FWIW, I've yet to find any lead acid which is vastly down on capacity but can still deliver its original peak current for starting a car on a cold day. That's not to say such a battery might not have some other uses.

I was told do that by a work colleague who had been in the submarine service in WW2 in an engineering rank. Only did it once with a battery on my Riley1.5 ,sometime around 1974. It did fix it for a while but wether it will still work on modern batteries which seem to have the plates much closer together I haven?t tried. If the Ops battery is constructed like an original one he may be lucky but I suspect compared to the car the battery is much younger and not so easy to get the muck out.

And unless you have a source of free distilled water then the money purchasing that may be be better put to buying a new battery which for a moggy won?t be too onerous at £50-£60 unlike the couple of hundred that modern tailored batteries seem to be.

GH

In message , Marland writes

I tend to agree. Top of my head I would have said the current battery is about three years old, but in reality, probably at least twice that. Modern sealed battery and yes, around 50 pounds to replace.

I don't see any problem there

of hundred that

You can of course use the one lot of deionised water repeatedly. Lead compo unds drop out quickly.

NT

Personally, I doubt it. Such a cheap and easy fix would be common knowledge. Probably from the days when the separators were made of plywood.

I've found a decent make battery - not abused - has a far longer life now than once was the case. My last Bosch did 11 years.

It's been known a long time, but most people are not suitable for the task due to the tipping about of acid. Nothing about modern batteries prevents i t working.

NT

A lot of modern batteries,and l think the op has said his is are described as sealed. They don?t have nice threaded filler caps easily accessible, what filling caps there are need a cover prised off to reach and in doing so the integrity of that cover is destroyed and with it the mechanism for holding the caps in place as they are not always threaded. So you need to bodge up a way to fix it all back together again and not leak in use. May be worth doing if you are stuck in some remote place in Africa and have no alternative but hardly worth the effort where you can purchase a battery for the price of few pints and a couple of posh burgers down the pub.

GH

revents it working.

'Sealed' lead acid batteries are never sealed. How exactly are they going t o leak when they're open *at the top* just like lead acids have always been ?

NT

The filler caps on the old style batteries screwed in firmly, on a so called sealed battery the equivalent caps are often just pushed in and the mechanism for holding them tightly is part of the battery top installed at time of manufacture and not intended to be removed again ,It is that part that you will have had to prise off to get access to the filler caps and in doing so may well have damaged that so it can no longer hold push fit caps tightly. The electrolyte may be happy when the vehicle is bowling along a smooth motorway but bounce in and out of some the poor surfaces on some roads and it will start to splash out.

GH

which is fairly easy

it doesn't need to

I've carried enough liquid in vehicles to know that's unrealistic. Even wit hout the rubber or plastic covers it would work. If you're the sort that cl imbs up mountainsides at over 45 degrees to the horizontal and literally bo unces the car going down, then I wouldn't.

NT