LEISURE BATTERY HELP NEEDED!!

[pd3k]

Hey guys, new(ish) here to the air cooled scene anyway,

really would appreciate some help.... here's the story, bought my "71 a weeke ago now, leisure battery never working o i thought i'd se what the problem was, turns out the fuse in the realy keeps blowing, so i get hold of the wiring diagrams in cornwall at the jamboree find out that one wire is conncted to the coil and another to the wrong (big) point in the alternator, sorted that, still no luck keeps blowing fuses

took the leisure battery out today, thought i'd charge it inside, topped up with de ionised water, puts on charge 3.2 volts and climbing excellent or not.... gets to about 6.7 v then the charger drops off, when the battery voltage drops to about 5.5v the charger kicks back in again until it reaches about 6.7 etc etc. you get the problem..... anyway, the leisure battery is 110ah and the charger can put out up to 5.6amps if that's any reasoning..... thanks if you read through this, lk forward to the advice

Sam

 

[Clarkson46]

To charge a leisure battery of that capacity from a normal charger could take a week if it is flat. Leisure batteries have very different charge/discharge characteristics to starting battery. From what you describe, it could be a faulty battery. Could you be more specific with what you mean by "the charger drops off"? Do you mean it cuts out on overload and resets?

 

[seamus]

To charge a leisure battery of that capacity from a normal charger could take a week if it is flat. Leisure batteries have very different charge/discharge characteristics to starting battery. From what you describe, it could be a faulty battery. Could you be more specific with what you mean by "the charger drops off"? Do you mean it cuts out on overload and resets?

what he said+
if the battery has run totally flat whilst on the van it will blow fuses ,as it will be pulling a lot of load from the alternator.

Most split charge systems have fuses at 10, 15, 20 amps, a stock alternator can give out 55 amps

 

[pd3k]

it's probab;y a faulty battery as it's been on charge for almost 24 hours now and hasn't managed to get above 6.9 v, and when the charger is turnde off it drops down, quite rapidly. the charger itself was getting up to 5.6 amps stayig there then it would cut out, and then when the battery ws reachin 5.2 ish volts it would kick back in again straght up to 5.6 amps, so not too sure if the charger is capable of charging a big leisure battery, or if it's jst that the battery if buggered, :?

 

[Clarkson46]

With a healthy battery, any charger will charge it. It is just a matter of how long it takes. In theory, a 110 Ampere/hour battery would take 22 hours at a constant 5 amps. However as the charge increases, the internal resistance of the battery rises and the current falls. So, in practice, the charge time will be considerably longer than 22 hours. To check if your battery is fully charged invest in a Hydrometer and check the specific gravity of the acid. I was always taught to check the SG every hour and when you get 5 consecutive readings without increase the battery is charged. The charging parameters apply equally when you are charging from the van. From all the symptoms, you have a faulty battery. If you buy a new one give it a commissioning charge before you fit it.

 

[Benyon]

A similar problem to I am having but I have not investigated yet...

if the battery has run totally flat whilst on the van it will blow fuses ,as it will be pulling a lot of load from the alternator.

If I bench charge the battery before installing it, how much will it need charging before I can safely put it back in without blowing the fuse?

 

[Clarkson46]

Read my post about charging a battery ^^^^^. Once charged the current required by the battery will be minimal. You need to manage the discharge of the battery correctly. No battery should be discharged below 85% of its nominal capacity. Correctly managed you will not blow fuses. Buy the hydrometer, Halfords do them around a fiver.