I've been thinking about my problems (with car that is ) relating to the battery. Typically I do only short journeys and as winter approaches they will often involve using the headlights, sometimes heated drivers seat and maybe the heated steering wheel - and on rare occasions the FBH .
I think I've seen a calculation on here but can't find it - if I start the car, drive for half an hour with lights on, seat and steering wheel heated as well as heated rear screen (plus stuff that happens anyway, radio/sat nave etc) will the battery be better or worse off at the end of the run, what I mean is will the alternator have put back all I have taken out of the battery as well as kept up with all the real time demands of the car?
I'm thinking that maybe I'm actually running the battery down given the way I use the car - its a fairly new Bosch C5 02 battery and the alternator seems to be putting out 14.8 volts according to the IIDTool.
The reason I'm thinking this way is on a recent trip to Scotland all in daylight with none of the electrical load I left it parked for a week and it just started no problem.

Thoughts/comments/observations?
 Geoff

Modern alternators are extremely capable.
If you start a car you use the battery, you can then have as much electrical load on the car after that as you like - non of the power comes out of the battery it is all fed directly from the alternator. In addition the battery at the same time is being recharged by the alternator to cater for the charge lost in starting the engine.
Going for a long run with everything on is no different to going for a run with nothing switched on as far as the battery is concerned.
If I go for a run including at night in rain hence just about everything on I come back and the battery sits at about 12.82V for 2-3 days due to surface charge which then dissipates leaving the battery at 12.62 for about the next couple of weeks if I don't use it.
Wasn't the case when cars had dynamos instead of alternators.
Those were the days.

All understood BUT given that I've given the battery a bit of a knock starting the car will half an hour put it all back given that the alternator is meeting the needs of the rest of the car when its running. I know they are good compared to dynamos but the current they can generate is not infinite - is 30 minutes enough? Geoff

i think its a characteristic of the range rover that the battery goes flat for no reason..

my td6 had a brand new 020 battery and that went 'weak' after just one year and i to did only short journeys with the alternator pushing out 14.5 volts... ... - .- -.




Y. O. L. O.
.

Thanks Stan,
Just like my old Cortina (happy days) the dealer said the whining back axle was a feature  Geoff

If the battery is in good condition and is capable of starting the engine without any fuss I would have thought a 30min run with whatever you have switched on as well would be perfectly adequate. I've never had a problem with a car not keeping up with the batterys needs whilst using it 1/2 hour each day in the depths of an Edinburgh winter for 20 years where I can guarantee "everything" was on morning and night.
A certain amount come down to maintenance particularly cable connections, hence the reason I have always fitted new additional earth strap cables between the engine block and the battery on my cars.
At least then I can guarantee the alternator output is going fully to the car and not trying to overcome dubious corroded cable connections.

your theory is probably correct NDFI if you get in your range a drive off straight away but in practice its ,unlock the doors , wait for the wife to change her dress/shoes/coat yet again and meanwhile the ecus are buzzing away for about 20 minutes draining the battery..if this scenario happens many times then i can see how the battery looses its state..  ... - .- -.




Y. O. L. O.
.

Coolio thanks both,
So no new alternator just yet, put off buying and changing the FSR and don't spend hours looking for battery drain, just make sure the cables are good and as a belt and braces measure get the CTEK on it once a week overnight to fully charge.
Simples!! Geoff

I've just realised that I've been taking advice off David Cameron and Mr Bean  Geoff

I have to admit with the FFRR I do start the engine when I first open it to go anywhere irrespective when I subsequently leave.
If I want to do anything on the car I have now got into the habit of connecting the Ctek for the duration.
Never did this with the old Disco or any of the other cars.

@ Geoff.. ... - .- -.




Y. O. L. O.
.

Hi Geoff and the problem is that you will never drive long enough to fully charge a lead acid battery from an alternator.

It’s not that an alternator can not fully charge a lead acid battery, it is that the alternator is not give enough time to fully charge a battery.

When your start a motor, you can replace the energy used in a 15 minute drive.

But this is only a small part of what is required.

Most new vehicles, particularly RRs, use a lot of power while the motor is off.

First off when the systems are going through their shutdown routines and then the power that is used once the vehicle is “asleep”.

So you also need to replace this used energy as well.

Then there is the one factor that is hard to address.

This is the fact that a lead acid battery not only needs to be fully charged, but it needs additional “conditioning charging”

This is something that takes hours to achieve not minutes of driving.

A low cranking battery can need as much as 10 hours of charging to reach a true fully charged start.

Even driving for 30 minutes every time you start the motor will not stop a battery from slowly loosing capacity.

As a cranking battery, it can loose up to half it’s original capacity and still do what it’s designed to do.

The only drawback is that this continual lose of capacity just speeds up the demise of a modern battery.

There are two basic options to both increase the charge capacity of a battery ( or to maintain it in a high state when new ) and that is to give the battery a periodical L-O-N-G charge.

The best this is to put the battery on a charge and leave it there for around 10 to 12 hours.

Most people think a battery is fully charge when there charger goes into float mode.

This is not the case, the most advantageous part of the charge cycle is the float mode as this actually conditions the battery, helping to either maintain a new battery at close to it’s originally intended capacity or to revive an older battery, by reversing some of it’s lost capacity.

The other option, if the vehicle is parked outside by day, is to fit a small solar panel in a window and let it maintain the battery. A solar panel can achieve the same results as a periodical charge with a battery charge.


BTW, you do not need a high current battery charger a small battery charger will do a much better job as it is gentler on the battery and this in itself can help extend battery life spans. 2007 TDV8 Lux

Last winter mine was coping well with running the FBH for 20mins before a run and then a 15min drive to work with the seats and windows on as well as the lights and the radio.

This only ballsed me up when i got stuck in the house longer than i wanted to be and the FBH ran for its full 30minutes or near enough at which point the battery would barely spin the engine and a quick jump start would be needed.

As long as your systems are in a good state you should be fine. If you are sat in the car for 20minutes on the drive with the key in the run position but the engine off i'd be a bit worried as its certainly draining the battery more than it needs to be.

Also dont forget when using the remote FBH it drains a good whack of juice from the battery which will take a while to recover so a 30minute drive should just about cover but it does make the engine last much longer than a normal cold start so the power it draws from the battery is worth it IMO and means less current draw as well when moving as the fans and heaters wont be on as much as from a cold start Oh and a diesel wont be drawing as much juice when the engine is running as a diesel does  FFRR MY06 facelift With TDV8 Alloys Zeros/ATR's
Mantec Sump Guard, Rigid Load liner, MY10 BT upgrade.

Currently (no pun intended) the car is on charge using the CTEK and will be left the rest of today, all night and all tomorrow. That should allow sufficient "float" time for the battery to fully charge.
I have connected to the terminals under the bonnet instead of up the old girls rear via the towing sockets. Hopefully she will appreciate this thoughtful and gentle touch on my part  Geoff

 Present :2008 TDV8 HSE
Gone Audi A5 2.7TDI
Gone Discovery 3 HSE
Gone Mercedes CLK
Gone Range Rover 2.5 DSE