Range Rovers Forum banner
1 - 5 of 5 Posts

·
Registered
2002-2005 Range Rover MkIII / L322
Joined
·
148 Posts
Discussion Starter · #1 ·
Today, I was attempting to get my new Fault Code Reader to recognise and lock to the vehicle's VIN number so I had the driver's door open and ignition switched on for about 5 minutes or so before 'HDC Inactive' came up followed by 'Air Suspension Inactive'. I tried to wind up the windows but she died half way so I switched everything off and connected my 15 amp battery charger. It's digital readout showed the battery at 40% of charge. (10.6v if I remember correctly)

This is odd because the car had started OK just minutes before and it had also been driven for 50km with no issues yesterday but within 10 minutes charging at 15 amps, the engine stated again at 80% of charge, bringing the Battery Charger's display up to 100% almost immediately. It almost seems the battery is carrying a 'surface charge' which will start the engine but will not 'hold' a load for any long period. (CD playing for 20 minutes whilst working on the car caused a similar issue last week)

The car is a relatively new purchase and the battery (850 CCA) could be shot. It even looks like the original 'factory' battery as it has the Land Rover logo on it but at 12 years or so, that would seem unlikely...

Is there a considerable battery drain with the ignition on and how long would you normally be able to have doors open, interior lights on, radio on, etc or ignition on before the battery voltage drops to a point where the CPUs start to shut down?
 

·
RIP Our Friend
Joined
·
27,834 Posts
Your battery is shot. Pretty miraculous if it really is the original 12+ years old. Just replace it and move on. There is the electrical troubleshooting guide in the FAQ if you wish to test the rest of your charging starting circuit and want to see where your readings should be.
 

·
Registered
Joined
·
1,783 Posts
i just went thru this with a similar 850cca. battery. i left the key on for 2 minutes so the fuel pump would run and see if the car would start sooner and the battery went down and it would not start. i had it load tested and the battery was toast. Just under 35 months old. Similar prior runs that allowed starts and runs long enough to charge it. I have forgotten how they can die from one minute to the next. Merlin has reminded me that the alternator is not meant to return full charge to a depleted battery. I really hope our alt. will not fail next from being overworked. those alternators do put out like crazy. i had noticed that the car had a few times kept a high idle when it was normally showing a very low tick over. Fortunately it was in my driveway and not on the farm with my 93 year old mother in the car.
 

·
Registered
2002-2005 Range Rover MkIII / L322
Joined
·
148 Posts
Discussion Starter · #4 ·
Sounds familiar. I think the batteries are so large compared with most cars, they'll carry a surface charge enough to start your RR but doors open or ignition on for 10 minutes and that charge is gone so the battery drops down to 10.5 volts.

I've just returned from a long drive down to western Sydney and bought a replacement as nobody within 50 miles of the upper Blue Mountains stocks batteries that big. Because I paid cash to the (ebay) battery warehouse, they upgraded me to the latest dual purpose, Deep Cycle (80AH) come Starter (900 CCA) sealed battery. Now to get it installed without damage to me or the car...
 

·
Registered
2002-2005 Range Rover MkIII / L322
Joined
·
148 Posts
Discussion Starter · #5 ·
Here's my test results with the new DIN 88T battery fitted and based on the Forum 'sticky' topic:

1a. No load battery voltage? 12.66v
1b. Engine off, all accessories on for 30 seconds: What voltage under load? 12.01v
1c. Engine off and all accessories off, after 30 seconds? 12.51v
2. Voltage across battery at idle (no electrical load): 14.45v
3. Voltage across battery at 2000rpm (no electrical load): 14.6v
4. Voltage across battery at 2000rpm (everything electrical switched on)? 14.6v
 
1 - 5 of 5 Posts
Top