Another D3 alternator bites the dust

[Tinman]

Just done another alternator. This is my third one, has only lasted 9 months like the previous one . The boss started the D3 up yesterday morning and without warning threw up a multitude of faults and the battery light remained on. Checking the output of the alternator it was charging at17.5volts, then would suddenly drop to 13.2 for a while then go straight back up then all the fault lights would show up, just like the previously installed alternator. Have got it booked to get it fixed under warranty. Does anyone know of any other alternator that can be used that is more reliable than the standard issued one.
Cheers

[bbyer]

You mentioned warranty so I wondered it the alternator was a LR rebuilt?

I ask, as apparently in the last month or so, LR UK has created a bit of an alternator shortage by stopping selling LR rebuilt as they are costing LR too much in warranty costs; as such, all they will supply now is brand new.

DISCO3.CO.UK - View topic - Denso Alternator shortage

[Tinman]

The second and third alternators were denso. They were fitted by my blue slip guy. The second one failed when he went to take it for a rego check. So he fitted the second and when that failed he fitted the third one. But just speaking to him he is not sure weather or not the supplier will give me warranty for the third one even though it was a replacement for the second one. So still waiting

[bbyer]

It sort of took three tries to get my rebuilt replacement going. The first lasted a week, the second had a five groove pulley noticed when it took the belt out and the third, a year later is still working fine.

In your case, the LR rejected Denso rebuilts had to end up somewhere so perhaps ....

[Tinman]

My blue slip guy is pretty good, been going to him for a while, he said both alternators were new, that he installed. But it does get you wondering.

[~Rich~]

It's not just about Volts, it's also important what it's doing on the Amp side too as I found out today! My car this morning had all sorts of weird things happening . The instrument panel display and interior lights where alternation bright and dim, the engine was slightly shuddering when this occurred and the info screen kept on resetting itself. Not to mention the radio cutting in and out too! Seems that some sort of spike has damaged my diodes in the alternator, Grrr I was going away tomorrow 4wding for the weekend. Too late to source a replacement and too much of a risk to other components if I drive it like it is.

My mechanic has come to the conclusion that these new day alternators have a service life of 100,000 k.

$800 from one supplier and $1134 from Alto just for the alternator.

[Graeme]

Seems that some sort of spike has damaged my diodes in the alternator

These alternators are fitted with Zener power diodes as a cheap way to absorb voltage spikes if the battery is disconnected while the engine is running. However Zener diodes have a much shorter life than standard diodes and often fail short circuit rather than open circuit, thereby rapidly flattening the battery at the same time. Zener diodes (AKA avalanche diodes) conduct in the reverse direction once their trigger voltage is achieved but they deteriorate with use and more rapidly with high currents and start reverse conducting at lower voltages.

[Tinman]

Hi Graeme, I think you are onto something here, a few weeks ago I went away for the weekend. The 12v to 12v battery charger switch had accidentally being switched on couldn't work out why the axillary batteries in the caravan were not running down until the engel stopped working in the car, then I noticed the switch was on. We were going home on this day so everything was transferred to the caravan fridge. The axillary battery was at 10.2 volts, on the trip home it changed and over the next few days showed no signs of destruction, it was two weeks later the alternator self destructed. Maybe this started the failure process

[Graeme]

Alternators often will produce more current than their rated output but aren't expected to do so for extended periods. A single incident shouldn't be of any concern but repeatedly charging 4 batteries at the same time is bound to have an impact although I still wouldn't expect the alternators to fail as frequently as your's unless the 12v to 12v charger is drawing excessive current.

[Tinman]

Its not often I need to use the battery charger only when its been overcast for a few days and the solar panels havnt charged the batteries enough. The Engel charger charges up to a maximum of10 amps with over current protection, so not a big drain on the alternator whilst driving. I am still at a loss why so many alternators have failed.