Battery was dead when i tried start it today.jumped it off another car and its been fine for rest of day stopping and starting. Its obviously loosing its "bant" so i have pit it on charge. How long should i charge it for?

No indicator on charger?

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No its an old one off my dad. Just has a high and low button.

This is the charger.

Few hours? Unless you've been doing lots of really short trips I'd get it tested to see if it's any good or not.

No instructions on charger?

Coz old chargers might not have a cut-off when fully charged - eeeek!

What about usually the battery itself has a GREEN indicator to indicate good charge?

I think on those the needle on the meter should drop the more charge is in it.

Until a hydrometer gives the same readings for three consecutive hours.

Had you left something on? If not, you might be better getting the battery checked and replaced (if required) asap.

 

Depending on the type of battery fitted to your car, that charger could easily kill it.

Ive disconected it to be on safe side. It was on about 3 hours.

Batteries prefer a long slow charge rather than a quick fast one.

A 4 AMP 12 Volt Charger like that is really only suitable for charging a battery up to about 48 Ah.

 

I use a 8 amp one for smaller batteries only, it does up to 120 Ah maybe.

I think on those the needle on the meter should drop the more charge is in it.

Yep, it's much the same as the one my dad used to use

I reckon itll be charged by now?

I tend to leave my porsche 924 on charge overnight on my trickle charger from Lidl - Does a good job and it was good value too.

 

I have a similar "brute" old skool charger - There's one setting that will provide enough bang to actually start a dead car.  But the buzzing noise it makes on that setting scares me

Assuming we are talking flooded lead acid.

I guess most batteries rarely get fully charged by a charger.    Most users are in too much of a hurry, because the car didn't start and they are now late for work. 

Or don't know how it all works and bottle out.

Or bang in so much current it rattles the plates to bits.

 

More than the OP ever wanted to know.

http://support.rollsbattery.com/support/articles/4347-measuring-specific-gravity

Nick - hence my post#11.However ,with older batteries there can be a problem with bad cell connections. Stick the charger on and charge shows low. Leave it some time and charge has wet the bad joint and the battery takes a dangerously high charge.

Might wanna get a good charger that can deal with sulphate

A very low amp one "may" improve the situation temporarily, but the sulphate tends to fall off and eventually shorts out the bottom of the plates.  This is what we call a terminal problem.  (boom! boom!)

Similar end result to using a high amp charger, but they tend shake out the lead peroxide filling in the plates.  But faster.

 

Since alternators became standard, batteries last until they don't, ie years longer.  Dynamo powered ones were lucky to go a couple of years. 

Once they start being funny(not), don't waste time, effort and money on pellets or chargers or other hoodoo.  Man up and get a new one.

A decent Bosch S96 @<£100 or similar or the one Mike Holroyd found for <£50. 

If the world economy wasn't in the toilet you would get some scrap value on your old one, too.

 

Only use for a charger is if the vehicle is left for a long time, then an optimate type thing will limit sulphation.

 

I've been on this forum a while now, and can't recall a post where someone had an alternator charging problem.  Tensioners, yup, one going round at the moment, but an actual alternator not charging? not so much.

Get a Optimate charger used for motorcycles boats etc,I leave my cars on charge all the time when not in use,these are smart chargers and will keep your battery topped up without any damage.I have used them for at least twenty five years,as long as you remember to disconnect before driving off. I must stress my cars are garaged,but you could use extension if it's in your drive.They do chargers that have a canbus system as well.

It's no point charging it if the battery is goosed,will only work if you have a short somewhere or you have left a light on or something.

Get a Optimate charger used for motorcycles boats etc,I leave my cars on charge all the time when not in use,these are smart chargers and will keep your battery topped up without any damage.I have used them for at least twenty five years,as long as you remember to disconnect before driving off. I must stress my cars are garaged,but you could use extension if it's in your drive.They do chargers that have a canbus system as well.

It's no point charging it if the battery is goosed,will only work if you have a short somewhere or you have left a light on or something.

Yup. Cant fault em

My bikes on an optimate 4 as we speak.

I think it drains and tops up the battery too? To keep the condition good? Does something clever anyway haha

I just leave it on all the time when the weathers like this

Yup. Cant fault em

My bikes on an optimate 4 as we speak.

I think it drains and tops up the battery too? To keep the condition good? Does something clever anyway haha

I just leave it on all the time when the weathers like this

 

That sounds like the use they were intended for - vehicles standing long term. 

 

If the battery is needing charge every day then its likely there is a problem.

Even short journeys and everything on, an alternator should be on top of that.  Are they all rated 120 amp? or just the tdi?

That sounds like the use they were intended for - vehicles standing long term.

If the battery is needing charge every day then its likely there is a problem.

Even short journeys and everything on, an alternator should be on top of that. Are they all rated 120 amp? or just the tdi?

Agreed. It is yeah. Shouldn't drain too quickly. Even with a datatool alarm the little battery is okay for 3 weeks or so atleast.

A car should be find for much longer i would guess