Old, flat, leisure (golf) battery

Inevitably leaving them flat or worse than flat for a long period of time effectively destroys them with an insulating sulphate coat on the plates. Measure voltage with the charger applied and I expect you will see 17v dropping to 5v the moment you disconnect it.

Put a filament bulb in series if you are worried that the charger might be facing a dead short inside the battery.

TBH a 12v battery with a terminal voltage of 5v is pretty terminal.

Yes, almost certainly, unless it was left on trickle charge for a lot of the time or recharged at intervals (probably better). Batteries (probably lead acid I guess) really don't like being left uncharged for long periods. Even if charged to start with they will self-discharge and over 6 years it will have become totally flat and, if left in that state, will be dead.

I doubt it will damage the charger but I also doubt if it will do the battery any good. Do a few checks first though:-

Is the battery a sealed one or has it got top up 'holes'? If it has vents then it's worth checking to see if there's any liquid in the battery.

What voltage is the battery? If you're going to try the car battery charger then you'll need to check that the battery *is* a 12 volt one. (The battery charger might be one that adapts itself to 6v or 12v, however that will add a whole lot more possible issues!).

Check that the battery actually is a lead-acid battery.

The battery is undoubtedly scrap. I've tried all sorts with depleted leisure batteries and even if it seems that you've mended it it will have tiny capacity and be effectively useless.

Is there only one battery? A lot of these things are 24V.

Dunno about golf buggies but some disability scooters drain the battery very slowly when not in use or on charge.

Bill

I feared as much. Not much point in being half way around a golf course with an unreliable battery.

A shame really because the (now deceased) owner could easily have put the battery on maintenance charge, as well as his motorcycle battery.

Note: he'd stopped using them years ago when his wife became ill.

Fortunately his kids took my advice to put the Audi car battery on charge whilst they take the prolonged steps of sorting out the estate.

Sealed Lead Acid 12v leisure battery (I think that is standard for older golf trolleys). See my response to Martin Brown for additional info.

I thought my Dad kept his scooter on charge, but when I found it, the charger was unplugged, I did plug it back in and it started flashing green, which I took as a good sign, later when I found the scooter key and tried to move it, it was dead as a dooornail.

I don't think it's worth enough to buy a set of batteries just to demonstrate it works and sell it ... the local mobility shop seem to have secondhand scooters coming out of their ears and weren't interested to even make any offer for it.

Lash something up with some car or even drill batteries, just to prove if it works? If it's 12V a chunky PC power supply could do it too.

Or just list it 'spares or repair'?

Theo

I thought about that, might have a look once I get "inside" it, but it weighs a bloody ton very difficult to manoeuvre

I have had some success with apparently sulphated lead acid batteries recovering some capacity simply by being left on charge for several days.

As said upthread, you need to be confident your charger set up is safe.

It will have. Leisure batteries do tolerate deep discharges much better but still get killed by sitting around flat for years.

It won't damage the charger. The charger may well refuse to charge a dead battery tho.

There's a lot to be said for constant current trickle charging - I've revived a number of batteries (lead acid and lithium) that way.

If you have a bench power supply with a constant current function, there's usually a voltage limit as well so you can make sure you never overvolt the battery. On a relatively low CC (1A or something) there's not a lot of energy going into the battery to cause troubles.

I don't own a 'smart' charger, and I get the impression they come with their own set of hassles.

Theo

You won't get a metre with those batteries, never mind halfway round a golf course. It's scrap. Lead acids are not hard to rebiuld if you fancy diying it.

you'll need to use an old charger for that, modern ones won't start charging. But you won't revive this one.

It's a very long time since I've seen an unsafe lead acid charging setup.

After such a long time, definitely not. However, for shorter periods, there is a circuit that will connect to a battery that will hold at least a little charge. The circuit repeatedly charges itself from the battery and then zaps about 250V back into it in very short bursts, supposedly breaking up sulphation.

It would be easy to do that manually with a nice heavy coil.

But not repeatedly over a period of time.

What should the voltage be, what battery technology is it are two questions you need to find out. I'd have thought a model number of the cart would be a good place to start a search. Brian

If they put it on a trickle charge for any length of time it will kill the battery. Storage needs a 'float charge' That is why Smart charges are 5 states ... ending in a 'Float Charge'

Leaving a flat for periods allow sulphate build up ... I have anti-sulphate devices on my batteries .... this puts a reverse polarity high voltage pulse about once every 2 sec ..... keep sulphate free.