Alternator issues

[pfield69]

Please see my other thread
Urgent help: Engine dies when stopping after long run
as this relates.

My battery is discharging the more I use my van.

At first i thought it was the carb heaters as they are constantly drawing 5-6A.

I have been fiddling all day and found that at high revs the alternator output drops
Here are some rough figures:
Battery voltage ignition off: 12.65v
Voltage @ battery on idle: 12.9-13.1V (carb heaters disconnected)
Voltage @ battery on fast idle: 13.9-14.2V (carb heaters disconnected)
Voltage @ battery @ 60mph: 13.2V and falling slowly.

This is with a new battery. Connecting the heaters drops voltage by about 0.3V more at speed. Connecting leisure circuit makes no differance.
I am using a GH alternator 90A.

Any ideas why at speed I'm losing power. Although I have an ammetre I can't keep it connected during testing.

[colinthefox]

Best guess would be your regulator/brush pack is finished. It's in the back of the alternator and held in by two screws. It's a ten minute DIY jon to replace and they cost around a tenner. Better still buy two and keep one as a spare, in the van.

[California Dreamin]

I would agree ^^^^^ chances are the brushes are worn or slip rings badly worn or burnt, causing poor contact at higher revolutions. However, please check earth leads on the alternator/engine bay & gearbox nose and of course, connections on the battery itself. Oh and a correctly tensioned drive belt.

Martin

[colinthefox]

Sorry! I forgot the loose fan belt.......simple stuff first.