Battery voltages

[GSMblue]

My wife tells me she took it out on Sunday for a 40mile drive. That alternator is getting changed out ASAP!

 

[PhyrraM]

I just had my new (to me) LR3 die on a short jaunt to the Home Depot. It started and drove fine, but on the last corner into the parking lot as the motor dropped to idle the dash lit up like our Xmas tree. It seemed like every system was throwing an error on the dash display too. It stayed running (but not shifting) long enough to turn in the parking lot and park it.

It wouldn't jump start after that. It showed .5 volts when the battery was hooked to the car and 5.0 volts when the cable were pulled.

We put a fresh battery in it and it started and drove fine the 5 miles home, but after the drive and about 15 mins sitting we noticed smoke and burnt electrical smell coming from the lower part of the motor.

I think I blew a diode (or something) in the alternator and it's basically causing a battery short through it.

I ordered a new alternator from RockAuto, so hopefully that's the only problem. Sound reasonable to you guys?

 

[GSMblue]

Sounds reasonable to me - but I am a newbie to the LR3.

My LR3 was dead this morning. I don't have a trickle charger or jump cables.... AAA are coming out to try and get me started. Local independent LR garage is on standby!

What a day!

 

[GSMblue]

What a day! The AAA guy could not get the LR3 started. The guy had it hooked up to his truck, let the battery take charge for 10mins. The crank sounded good, but the engine would not fire up.... so they loaded her up in a flatbed and towed her to my chosen garage.

Question: is there any risk that any damage could have been caused from trying to jump the LR3???

 

[GSMblue]

Ok, garage report is in:

Blown fuses for fuel pump and heated seats (I don't have heated seats!)
Alternator is dead
Some wires in the harness behind the battery were shorted
Lots of communication codes were cleared
Code for air compressor (not doing anything about that right now)

So, I am in the whole for $1300... Sounds spendy to me.... What do you guys think?

 

[GeoRover]

Hmmmm... Based on the original symptoms, it usually is the battery or the alternator, or both since dying alternator can take the battery down with it by not charging it fully. Plus the alternatior dies in phases, three to be exact. The early symptoms usually are not fully charged batteries and then other error codes etc.

With that said, I will opt for just changing the alternator first. That may take care of all the resulting and related problems. What will they charge for that? Parts and labor?

 

[GeoRover]

I just had my new (to me) LR3 die on a short jaunt to the Home Depot. It started and drove fine, but on the last corner into the parking lot as the motor dropped to idle the dash lit up like our Xmas tree. It seemed like every system was throwing an error on the dash display too. It stayed running (but not shifting) long enough to turn in the parking lot and park it.

It wouldn't jump start after that. It showed .5 volts when the battery was hooked to the car and 5.0 volts when the cable were pulled.

We put a fresh battery in it and it started and drove fine the 5 miles home, but after the drive and about 15 mins sitting we noticed smoke and burnt electrical smell coming from the lower part of the motor.

I think I blew a diode (or something) in the alternator and it's basically causing a battery short through it.

I ordered a new alternator from RockAuto, so hopefully that's the only problem. Sound reasonable to you guys?

Sounds about exactly what I would do. Keep us posted.

 

[PhyrraM]

Sounds about exactly what I would do. Keep us posted.

Installed the new (Desno remanufactured) alternator this evening. Considering it's a Jaguar based V8, crammed into a full frame chassis, using British ingenuity, it was a suprisingly easy job.

I made sure the battery had a full charge and she fired right up. No smoke, no fireworks, no drama. It took a few minutes for the ECU to re-learn the idle and stalled out once. Drove around the block and didn't see anything to worry about.

All seems fine now and the volt meter reads 13.5 at idle. The electronic throttle means I can't easily measure the voltage above idle.

I've never seen an alternator fail in such a way...direct short through the rectifiers...but all seems well.

 

[GeoRover]

Installed the new (Desno remanufactured) alternator this evening. Considering it's a Jaguar based V8, crammed into a full frame chassis, using British ingenuity, it was a suprisingly easy job.

I made sure the battery had a full charge and she fired right up. No smoke, no fireworks, no drama. It took a few minutes for the ECU to re-learn the idle and stalled out once. Drove around the block and didn't see anything to worry about.

All seems fine now and the volt meter reads 13.5 at idle. The electronic throttle means I can't easily measure the voltage above idle.

I've never seen an alternator fail in such a way...direct short through the rectifiers...but all seems well.

Awesome! Looks like you got yours resolved. Battery voltage reads exactly right. When car turned off, a good battery should read 12.xVolts, at idle around 13.5volts and at crank around 14.2 - 14.4ish volts. Looks like your alternator is now working and with the new battery I suppose you are set at this point.

Do you know the amperage of your new alternator? Make sure it is rated for LR needs or better. I believe LR needs minimum 120amps alternator to cover its load plus a little extra.

 

[PhyrraM]

It's a 150 amp alternator. I chose the Denso reman because from all the reading I did it seems that Denso made the OEM one.

It also appears that the ECU controls the alternators output through a PWM signal of some type. FSM talks about regulating the voltage to the temperature of the battery.