Hi folks.

I've recently being having a flat battery in the mornings. I've had 2 New batteries so I think I can safely say that the battery is fine. I've removed the alternator... The unearthing all seemed fine. The voltage across the battery seemed to be dropping when I had all lights, heaters on etc. But at idle the alternate seemed to be doing its job. Just it dorsnt seem to keep up when under load?

As I said I've now got the alternator off and am looking to replace the regulator. Looking for any advice or ideas to confirm my thoughts or give me a new avenue to investigate.

Thanks folks. MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Did you check the FSR before doing all this? [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!

Forgive the ignorance but what is the FSR and how is it checked ? MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Ah! Final stage resistor ?! I know it had a new "hedgehog" a year ago... How do you check it ? MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

From memory it causes the little fan to keep running and stop the car from going to sleep. 2 options, park up get out and lock the car. Go in have a brew watch top gear on Dave then go out and look into the car at the gear selector. If the red light is still in the "P" position the BCM hasn't gone to sleep causing the batt drain. Option 2 is lock yourself in the car with iPad, iPhone, laptop and surf the web waiting for the car to go to sleep and listen for the little fan in the dash to stop. [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!

Thanks for that . I suppose ill just have to do than when the car is back together now. Definate possibility though. Any one have any more thoughts on the alternator , ref the voltage dropping on the battery when under full load for 10 mins? MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Have you tried the hidden menu's to see what your getting? When my alternator died a few months back it couldn't keep up with the demand and the voltage just kept dropping. It was like the scene out of Apollo 13 when they were trying to power up with a small voltage. Mine was the reverse to see if I could get home as the systems started shutting down to keep her running! We made it home, JUST!

If the car was at idle while doing the test, I would imagine the voltage would get to a certain point then the ECU's would increase the idle to make the alternator do more and charge the bat. I know under load while driving mine produces 13.7v give or take a few mV.

That's why after a flat battery they say to drive for 20mins as its better than letting the car idle. [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!

Did you get the battery / alternator light on then ? I had no light on my dash at all . Not not tried the hidden menu just used a fluke MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Also does anyone know what the battery voltage should be when under heavy load I.e. heaters , lights etc. ? Should it stay around 14v or is it normal to drop off ? MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Not sure when it died as drove to work fine, then 12h later started up to come home and the batt light was on. Brought the batt voltage up in the hidden menu and made a dash for it. No radio, heater etc and it just got me home 16miles 20mins drive. Had no ABS, HDC, air suspension, transmission failsafe by the time I was home and the battery was down to 8-9v by this time. [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!

The voltage under heavy electrical load *should* remain about the 14.6V mark provided the engine is running above idle. If the voltage is slowly dropping over time, its most likely the alt.

Long story short, the alt is designed to work best in a certain rev range ... with idle being at the very bottom edge of that range ( a bit like the power band of a engine ). Where the alt may just manage to power things at idle, it will be able to put out much more power if the engine is running above 1500rpm for example. V8 or else ...

Thanks to rob and fisha for the advice. I should get the regulator for the alternator next week and will update this thread when I have put it back together . MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

Well I got my alternator back. And the car is running. Nothing has been done to the alternator as the guy didn't want to replace the regulator in the end after phoning up the Bosch alternator technicians. He doesn't want to replace it as he doesn't think it will make a difference. So I am back to square one. Other than having now tested the FSR in the way Rob described of locking the car and checking if the red park light has extinguished after 20 mins or so... Which it has. Does this eliminate the FSR ? I still think it is the alternator as I am currently on my 2nd new battery in a short space of time.

I am away at work now for a week or so. So ill see what happens when I return ( it will probably be completely dead). I'm taking it back to the alternator guy to do some more tests with his clamp metre when I get back.

Still thinking New regulator, or possible just a whole new alternator. Anyone have a spare good one for sale ? MY2010 TDV8 Vogue Ipanema Sand
2002 V8 Vogue Oslo Blue - Gone.

THere was talk on the web when I looked at replacing mine that the design of the winding has the potential to fail was such that if a winding did fail, then that could then cause the regulator and diodes to fail as they struggle to deal with it, and that even with replacing the diodes and regulator, the dead winding would still remain and reduce the life of the new parts.

I sourced a regulator to fit to mine ( which I binned ! - sorry ! ), but struggled to find a source for the exact diodes which are a solder-in item.

I actually still have my old alternator sitting on the bench in the garage - its the duff one that I replaced, but for the cost of the postage you can have if you want to rip apart.

In the end, I decided on a new alternator was the solution rather than trying to fix it / refurb it.

Going right back to the start:

When you talk about the voltage dropping with a high electrical load ... how are you measuring things? If it isn't a digital meter, then its pointless. for me, the voltage dropped really quite slowly. as in 0.1V every few minutes ( or longer ) when at idle. Also having charged the battery overnight on a trickle charger, it would maybe say 12V before start and drop significantly after start like 11.4V ( cause it used up a lot of energy to start it )

You need to post up some actual values of what your seeing too. Such as the following one after another: (voltages measured across the battery terminals )

Voltage when off before starting.
Voltage once started and running at idle
Voltage at 2000 to 2500rpm
voltage back at idle
voltage after 10 to 15 mins of idle ( or how long it takes to lose 0.1V )
engine off - voltage at standstill
wait 10 mins
voltage before starting
voltage after starting

In short, if the voltage once the engine is running jumps upto 14.6V ( i think it should be that value ) and stays there, then to me the alt is working as it should

If the voltage drops after each start and slowly falls at idle ... or its not jumping upto to 14 to 14.6V and staying there, then that would suggest the alternator.

If the alt appears to be charging, then you could be looking at the FSR as already mentioned. I'd then be looking at wiring up the voltmeter so it can be read from outside with the car all locked up. Then measuring it every half hour to see what the voltage does. If it drops steadily, and notably over time, then that to me would suggest FSR type issues. To be honest compared to the cost of an alt, then you could just fit the newer style FSR part anyway ( its not hard and probably would be a preventative thing anyhow. ) V8 or else ...

If your measuring the voltage drop shouldn't the fluke in inline? Just asking now for future reference. Wood I can give you a phone number of the place hat record my alt, they were very good. Sold me a brand new copy one for £240 but it didn't last 4weeks, then gave me a recon unit for nothing but with a full refund . They said it would cost about £80 to recon my alt. Need to get my old one repaired and stick on the bay. [img]http://www.fuelly.com/driver/rob2529/range-rover[img/]
04, 4.4V8, Vogue Oslo Blue with LPG.
"You can sleep in your car, BUT you can't race your house!!!!"

If something can't be fixed with a hammer....... You have yourself an electrical fault!