480 Low rate of charge from alternator

[malcolm mcinnes]

The car is a 1994 GT model. The alternator appears to be charging the battery at 13.3 volts ( reducing to 13.0 volts with the radiator fan on ) instead of 14.5 volts. The battery is going flat after a few days.

History:

. The battery is only a year old, has passed a drop test & retains charge when disconnected & so should not be causing or contributing to the problem.
. There is no voltage drop from the alternator through the fuse to the battery .
. The positive battery terminal & the negative terminal & braid have been replaced
. The original alternator was replaced two years ago with a Hella.


Although the alternator is relatively new & has done very few miles - is it still the most likely component to be faulty or are there other checks that could
be made before splashing out on another unit?

Any advice will be much appreciated

[Clan]

It's probably a non genuine alternator , invest in a decent one and problem solved hopefully as long as the wires are secure on the back

[Paul240480]

One possibility is that the brushes on your alternator have had it. Should'nt have as its a fairly new alternator, but worth a look. General advice I've heard is that the alternators rarely fail, more often then not its the brushes.

A replacement brush box can be had for around a tenner (got mine from Braydons for my 240). Easy to fit on my 240 without having to move the alternator, not sure if it's so easy to get to on the 400's as I've never tried.

They're only held in place on the alternator by two screws, just a case of if there's enough room to get your screwdriver in.

Another thought, is the alternator the right one for the car? Perhaps it's a less powerful one & so not up to the job....................