How far can you drive an LR3 / Discovery 3 without an alternator?

[morrisdl]

Short answer easily 1 hour per 900amp battery with wipers and defrost on (no headlights). Once it shuts off the suspension compressor, you have alteast 45 min of power remaining.

After this little swim killed my alternator 3 hours away from home, I decided to give it a try and find out.

We got about an hour away from camp on the factory 900amp battery before things started going haywire. I was hoping for a bad battery, so we went to the most helpful advance autoparts store ever. They tested it and not a bad battery and they didnt have an alternator - which I didn't really want to tackle in the parking lot anyway. They pulled out my battery and recharged it. While we waited I did some quick math and figured I would need a 2nd battery to make it home. Luckily they were on sale and there is a nice spot in the LR3 for a 2nd battery. Not ideal with out the isolator, but once charged up I connected the positives and the new battery to grounding stud (parallel). With 2 batteries, I made it 2 hours home before systems started shutting down again.

They really built the rovers to go places where a dead battery might mean dead passengers. Over the course of 45 min: 1st the air suspension compressor turned off and locked it at normal height, then ABS turned off, Traction control, Transmission faulted to limited gears, HVAC, and air bags all turned off. When we got how it would still barely start it backup to move around the driveway. Interesting LR built in intelligence most people will never experience. It worked and got me home! I guess I could have done the same thing by pulling fuses, but I didnt think of it until it already started killing sub systems. Thank you Land Rover!

 

[Campndad]

Saw the same thing on two different vehicles one an lr3 and one an lr4. Just a bad place to put an alternator below the wading depth.

 

[iowalr4]

That is very cool that they designed the electronics to do that.

I thought that the alternator was made to handle water? No? Are the high voltage parts not sealed up?

 

[morrisdl]

Maybe designed too, but after 110K miles of northeast salted winter roads I think the alternator was just looking for a stray to break. Agreed bad spot. If they are going to put it that low, at least make it so only the front skid plate has to be removed to replace it. Book says the fan and shroud, the skid plate, and the right front fender liner need to come off.

 

[nwoods]

It's a lot easier with the fender off, but not necessary if you are okay with using your hands and not quite seeing what you are doing. I agree that the cascading disablement process is useful. It's called the "Limp Home Mode" and it works well. I needed it once. Lost the CANBUS system in Death Valley once, drove the 150 miles to home okay. Had to shift manually. I've never seen that many lights on the dash before

 

[spikemd]

Ouch! Most trucks would have stopped working well before the LR3 did.

Is the alternator that vulnerable?

 

[A.J.M]

Tbh, the alternator sits low on the diesel ones as well, welcome to having engines that came from other makers and adapted to suit.

Mine was replaced by the previous owner from wear and tear at 98k. The D3/4's like a good supply of power and the alternators get a hard life. Realistic life is 7-9 years before you would consider changing it.

The limp home mode is great, there are few things that will truely disable a D3/4 bar total engine failure.

 

[stioc]

I don't think it's anything specific to the LR3/4. Most cars will continue to run, the defrost, wipers, a/c, headlights etc will consume the most amps and should be shut off- this is where the battery's reserve capacity comes into play. I once drove a 93 volvo home when it lost the alternator on the fwy and a 99 BMW when it lost the alternator in a parking lot. The first approx 40 miles, the second only about 10 miles but could've gone longer if I needed to. Of course, there's a possibility that some of the modern cars like the Tesla will refuse to even turn on and display a message "Self-preservation mode initiated. Please plug the charger in and exit the vehicle before the eject sequence is initiated"

 

[Jwestpro]

Maybe designed too, but after 110K miles of northeast salted winter roads I think the alternator was just looking for a stray to break. Agreed bad spot. If they are going to put it that low, at least make it so only the front skid plate has to be removed to replace it. Book says the fan and shroud, the skid plate, and the right front fender liner need to come off.

So the battery was a standard factory model it sounds like, right? When you say "900 amp" I assume you mean CCA, so it sounds like it to me but usually for run time the useful number would be the "amp hours" as it refers to hours at a given draw.

 

[morrisdl]

Yes - OEM 900 something CCA. I didnt see an amp hour rating on that one. The GRoup 34 AGM battery I added was similar spec. I have since disconnected the 2nd battery since the boat needed a new on anyway.

 

[unseenone]

Good to have a general idea of how far you can go.

On Batteries I prefer the 9A94 Deka is a primary, secondary 9A47 AGM Intimidator series...

 

[Jwestpro]

On Batteries I prefer the 9A94 Deka is a primary, secondary 9A47 AGM Intimidator series...

Why those over others? I don't need any immediately but am curious for the future. Actually, the wagon could use a new battery soon and Odyssey says it's the 1350, which I could pull from the Land Rover if there is something better suited to heavier use in the LR3 primary starter location.