battery charging

On a RR, the battery slowly loses charge. I'm struggling to understand
if it's the battery (which has tested fine) or the charging.

Initially I was puzzled because it mainly discharged on longer trips
(over 250 miles and it would start to fail) yet on short frequent runs
it seemed to be charging and holding charge fine.

I had to charge it overnight with a 4 amp charger and next day it would
be OK - this was done weekly. A week of short trips and it needed some
help, but one long trip and it was struggling.

I'm prepared to accept that maybe on the longer run more current is
drawn then the cumulative effect of a weeks worth of short trips, but
why does a mains charger actually charge the battery when the car
itself won't?

I'm now starting to question if it's the battery or the alternator.....

<[email protected]> wrote in message
news:[email protected]...
> On a RR, the battery slowly loses charge. I'm struggling to understand
> if it's the battery (which has tested fine) or the charging.
>
> Initially I was puzzled because it mainly discharged on longer trips
> (over 250 miles and it would start to fail) yet on short frequent runs
> it seemed to be charging and holding charge fine.
>
> I had to charge it overnight with a 4 amp charger and next day it would
> be OK - this was done weekly. A week of short trips and it needed some
> help, but one long trip and it was struggling.
>
> I'm prepared to accept that maybe on the longer run more current is
> drawn then the cumulative effect of a weeks worth of short trips, but
> why does a mains charger actually charge the battery when the car
> itself won't?
>
> I'm now starting to question if it's the battery or the alternator.....

I'm sure if you get a weeks running then the battery it is holding its
charge you are losing charge because the alternator is not putting enough in
to maintain the charge easy way is to have a word at a reconditioners they
can easily check the output of alternator with a collar type ammeter.
I'd be inclined to suspect the Diode pack on the alternator is giving
trouble or it could be something as simple as the drive belt slipping or
even worn brushes and as I keep banging on about the quality of the
connectors on land Rover kit clean the terminals they do give trouble
regularly
Derek

Derek <[email protected]> uttered summat worrerz funny
about:

> I'm sure if you get a weeks running then the battery it is holding its
> charge you are losing charge because the alternator is not putting
> enough in to maintain the charge easy way is to have a word at a
> reconditioners they can easily check the output of alternator with a
> collar type ammeter. I'd be inclined to suspect the Diode pack on the
> alternator is giving
> trouble or it could be something as simple as the drive belt slipping
> or even worn brushes and as I keep banging on about the quality of the
> connectors on land Rover kit clean the terminals they do give trouble
> regularly
> Derek

Kick it up and see what voltage you get at the battery with the Engine
running.

Around 14 Volts is a good sign. Then check it after it's been stood and the
engine is cool... then again , check it in the opposite order. If your owt
like me by the time you fight a path to the garage to the multimeter, then
find out it's not where it should be , then trash a bit more garage and find
it , well the engine wil be cool regardless ;-)

Lee D