If you suspect you have battery or alternator problems This is an inexpensive but useful voltmeter to allow you to simply check where the problem might lie.
Plug it into an accessory socket with the engine off and you will read battery voltage. ( Depending on whether your sockets are permanently live or ignition controlled you may need the ignition on)
Leave it in overnight and read again in the morning and you can determine any voltage drain from the battery.
Plug it into an accessory socket with the engine running and you will read alternator voltage.
Takes a lot of the guesswork out of where the problem actually is.

Also, if you suspect that your battery or alternator is not working correctly you can use the in car diagnostics to see what the voltage is and how its charging.

Simply use the 753 hack and go to vehicle signals screen. Discovery 4 HSE
1998 110 TUM HS FFR Hard Top XD WOLF
1982 Series 3 Hard Top

*Gone:L462 D5 HSE LUX, L663 Defender 110 HSE, Discovery 3 HSE, 2014MY Range Rover Sport 5.0 Supercharged AB Dynamic; L405 Exec Vogue SE 4.4, 5.0 Supercharged Autobiography, Defender TDCi XS CSW, Defender TD5 HT, Vogue SE TDV8, Vogue TD6, RRSport SC 4.2V8, Classic 3.9 Vogue Auto, Land Rover Series 3 SWB

Does that apply to all vehicle years?

And also http://www.fullfatrr.com/wiki/Secret_Codes

for 02-05 number 9 on the list.[/b] .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

Previous: L322 Range Rover TDV8 3.6 2008; L322 Range Rover TD6 3.0 2002; P38A Range Rover V8 1999

Thanks for that.
Easier to plug a voltmeter in.