Do you have a battery smart charger? I'd put it in test mode on each battery and test the remaining CCA and also charge it to 100% and see what voltage it reads. Anything less than about 70% can cause issues. 2015 Range Rover Autobiography 4.4 SDV8

I charged using a ctek that took the charge over 80% of capacity which didn't make any difference. After the 5 hour charge and a 45 mile drive 2 days later Halfords said it was around 70% on the CCA. The strange thing with the battery is low voltage, typically 12.1V to 12.3V.

Two days later after sitting in the driveway its at 12.2V and 42% so there might be a can bus wire short going on.

What’s the voltage with the engine running ? Should be circa 14.4 is less than that probably an alternator issue 2012 tdv8 Westminster arrived Jan 19 gone Dec 23

200 TDi discovery bobtail gone
RR classic v8 bobtail gone
300 tdi Discovery 3 dr gone

Sounds like the battery and nothing more complex than that, to me. Remember cold weather can quickly kill weak batteries.

I'd be looking for a 100% charged voltage to be at least 12.5V and a CCA test run showing at least 700A. 2015 Range Rover Autobiography 4.4 SDV8

Last edited by garyRR on 31st Dec 2024 7:23pm. Edited 3 times in total

The car charging voltage on a running engine is 14.8V so there is nothing wrong with the alternator.