mystery battery drain

[rockrover]

battery just goes dead after sitting a day or two. was told it could be the alternator. i have checked for battery drain from other sources. any body have any advice.

[BullDogSix]

CD player...it remembers last spot on cd

[PriestlyDeacon]

Originally Posted by rockrover

battery just goes dead after sitting a day or two. was told it could be the alternator. i have checked for battery drain from other sources. any body have any advice.

Going through the same thing at the moment with my 91 Classic. It'll be fine for a couple of days or even weeks at a time, then I'll go to start it and it won't have the juice to turn over.

I'm not positive by any means, but I'm ruling my alternator out for now because once I jump my truck, the battery gets charged and my headlights/interior electrics are strong. When my alternator in my Subaru went, even with a jump I'd have to romp the gas to keep the electrics alive.

Weirdness.

[repete]

It can be so many things. I once had my a/c comp. clutch stay engaged with my key off. Disconect the pos lead at the batt. and hook a test light up between the pos lead and the pos term. on the batt. you'll see that the light should be very bright. begin to remove fuses 1 by 1 and see if the light dims. try the alt. as well. the light won't ever go out completely, since there are items like the radio that has memory. If you have an amp clamp, It would be much more accurete.

[p76rangie]

Could be just a dud battery. If you have a volt meter (essential item if you own a Rangie) measure the voltage at the battery when the motor is running at around 1500rpm. It should read a bit over 14 volts if the battery is low. Anything above 13.5 volts is probably acceptable, but below this would indicate an alternator problem.

[Expedition Nutter]

On the P38, the next generation of Range Rover, the battery will mysteriously die too. We have found out that it is caused by the computer checking false RF signals - it checks to see if someones trying to unlock the vehicle with the alarm remote at every RF signal it receives in the area! Needless to say, don't park for long periods of time. Not sure if this applys to the RRC, but you might consider it.

[57loboy]

Originally Posted by Expedition Nutter

Needless to say, don't park for long periods of time.

Guess those w/P38s need to keep driving them and never park them...

[stolenheron]

you need to get the battery checked before anything. you can get a bad cell and it will cause the whole thing not to charge. any aftermarket electronics like a alarm system?

[ohiorover]

I had the same problem, mine seemed to be the CD player or the central locking system. I put a volt meter on it and it would randomly draw a little juice now and again. I just put a quick diconnect on the positive teminal and twist it off if its gonna sit awhile, you have to punch in the radio code everytime.

[TerryS]

Both the Lucas, and Magnetti Morelli alternators have the same regulator pack inside them. One diode can fail, and while the alternator will still charge fine, with full output, the failed dioded allows current to flow backk to the alternator after shutdown.
About an hour after you shutdown, put your hand on the alternator. If it's warm, or, likely hot, that's likely your trouble. That's not to say it couldn't be something else, in which case, one by one pulling fuses, with your ammeter in line with the battery and positive cable will be the quickest way to isolate it.

[stolenheron]

there is another thing called a battery brain. its like a backup batter than plugs up to your terminals, it will always leave enough juice in it to start up the vehicle and basically have a built in jumper.

[lindzmk2]

Also, silly questions: are you leaving the key in the ignition (like if the truck is parked in a garage) or any cell phone chargers plugged in? Do you ever shut off your Rover with the truck still "in gear"? My Dad used to do that to my old 95 SWB (put up the e-brake, left the truck in "D" and the key still came out of the ignition) and it would be dead the next day.

My FACTORY battery in the 95 SWB lasted until January 2007, can you believe it?!

When I've lost the alternator (in both the 95 SWB and a 95 Disco), I always had the "alternator feedback" like a buzzing sound coming from the radio. And the lights were dimming when the wheel was turning (as in parallel parking) as well. I just assumed those were easy "tells" for when the alternator was going...

[OkieRover]

Terry nailed it. That's been my experience twice.

[DevynsDad]

At this point I must bring up the simplest possible problem...check the water in your battery. Long story short, I had a nearly new battery that died on me. After much bitching, moaning and checking of electrical parts, my wife's dumb-ass cousin came by and popped off the cover on one of the cells. Guess what? Bone dry. I felt like a complete jackass and he has never let me forget it.

[Expedition Nutter]

Originally Posted by 57loboy

Guess those w/P38s need to keep driving them and never park them...

Well, like for days or weeks at a time... for instance in a high traffic parking garage at an airport.