Rover 75 CDT, charge light coming on

[Keith]

It's the time of year when the car electrical system is under maximum load

Recently my charge light has been coming on for a few seconds very occasionally just after start up when HRW Blower Lights etc are all on. Normally that would suggest the Alternator belt is slipping but on the M47 engine the belt is not adjustable.

Can they stretch, or the tensioners seize up? The belts don't have a service life do they?

I am tempted to get another belt and then investigate anyway. Hope it is not the alternator itself

[DeeCee]

It's the time of year when the car electrical system is under maximum load

Recently my charge light has been coming on for a few seconds very occasionally just after start up when HRW Blower Lights etc are all on. Normally that would suggest the Alternator belt is slipping but on the M47 engine the belt is not adjustable.

Can they stretch, or the tensioners seize up? The belts don't have a service life do they?

I am tempted to get another belt and then investigate anyway. Hope it is not the alternator itself

Posted some info here ...
http://forums.mg-rover.org/showthread.php?t=160695
on post #6, link gives some useful info, including Voltage to temperature output graph.

[DeeCee]

The alternator has failed !

Spent a couple of days trying to convince myself that the 2.5 year old alternator was not faulty.... It is !
Valeo made in France... not keen on French electrics.

Probably caused by all my messing about with the Nav system.
Happened after I had been playing with the Nav system for about a hour... now upgraded to V28 and info button operational.

During my checks/ tests found that when Glow Plug preheat is on there is over 80 Amp total load on the battery, they turn off after about 5 seconds, depending on ambient temperature.
But when the engine is started there is a post heat cycle, maybe this is the reason you got the warning light, belt slippage or Alternator fault !

Just guessing what caused my problem...

With all my messing about the battery was very low, maybe when the car was started the load of the Glow Plug post heat together with high charge required for the low battery, also had the headlights on, was too much for the alternator.

The charge light started flickering and the battery warning appeared on the message screen.
Recharged the battery out of car with slow charger...
took three days before the green indication appeared on the battery.
Installed back in the car, no difference, warning light and battery warning still shown.
Checked the Alternator belt, checked it was receiving the field/exciting voltage and was turning, all looked ok but no output.

Removed Alternator, stripped and checked field brushes, all looked ok, could not see any other faults.
The windings looked very dark in colour, but no burnt out smell.

Ordered new Alternator from Rimmers. £131 inc P&P.... good price, got the Dec 10% Discount.

... Awaiting delivery

[Livermpj]

Hi Keith,
My charge warning light used to come on (usually after a cold start, with post-glow, FBH, HRW, aircon & headlamps on, at low engine speeds).

At first I thought the alternator was faulty, because the battery voltage was quite low, but actually the battery was faulty - 1 cell was duff, so effectively I'd got a 10V battery.

You could try measuring the battery voltage with the engine off, headlamps on - it should maintain about 12V if all cells are working.

PS. Battery failures are more common than alternator failures, and luckily the're cheaper!

[DeeCee]

New alternator fitted, all ok now !

..... Not a nice job to do.