We all know short journeys kill the battery because you take so much out to start the car but how long do you need to drive before you have replaced what you took out of the battery. I know there are lots of factors involved like lights, heaters etc but anyone hazard a guess at some ball park figures. 2010 3.6TDV8 Stornoway Grey/ Black interior - gone
2005 4.4V8 (M62) Bonatti Grey/ Parchment interior - gone
1998 4.6HSE Blue/ Cream interior (can't remember exact colours) - gone
1977 White - gone (should have kept)

If mine gets started it does a minimum of 13 miles (nearest civilisation) and neither this car, nor the D3 before, ever had low battery issues. Mind you, it'll do a 50 - 60 mile run at least once a fortnight so that may help

So I guess my answer is - I don''t have a clue

Sorry!

there cant be a straight jacket formula. depends on multiple factors :
condition of battery
charging/discharging ratio
load on battery etc

but letting the car reach optimum temp and decent run every fortnight is gud. and batteries last 3-4 yrs so more chances of battery going kaput if its too old.

I keep mine on a CTEK MXS5 battery conditioner as I don't do many miles and these cars have a lot of toys sapping power even after the car is off..

Was thinking the same too as I have started to use the remote heating most mornings for 5-10 mins and most of the time I only do 4-8 mileas a day however may do a 200 mile round trip every couple of weeks. Assume this also benifits the engine as it helps to get it to operating temp sooner.

the FBH works on heating the int if you use timed climate, unless it is <20deg C then it prioritises engine with some cabin heat.

Having said that it heats the coolant either way so has to help with engine warm up.

If its coldish (below 5deg? cant remember figure) FBH will come on when you start the engine anyway to help warm up process irrespective of timed climate.

Battery, when i was having battery issues and had to jump it the 8 mile school run had it charged enough to start again no problem. Cheers

James

I've always worked on 6 miles to recharge a cold start, but in reality, it's a length of string thing. Dont think it will be much less than that though.

I'd like to say I worked this out for myself but I haven't got enough fingers....!!!

Quote from a physics website I found....

"If the car draws about 350 amps for 3 seconds to start. That works out to be 0.29 Amp-Hrs.

The alternator on a car can easily restore that amount of energy in 40 seconds at about 40% efficiency. Which means about 0.62 Amp-Hrs are needed from the alternator to recover the battery."

Don't know if the diesel is the same but the alternator on the early V8 doesn't put out anything for 30secs to aid starting so 1min 10secs and your battery is topped up again....

Sounds a bit quick to me, suppose it must be the FBH drawing loads of current on the diesel that gives battery problems, plus heated seats/wheel/windows etc..... Pete
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2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
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