How bad is a flat battery?

[donatien]

Haven't used the Griff for about 3 weeks now and the battery is as flat as Patsy Kensit.

No real worries with that, when I want to get the car up and running I'll charge it up or get out Green Flag to boost start it.

Thing is - does it do any real harm to keep the car in this state for 3-4 weeks? I realise the ECU will reset so it'll need a good run to adjust and also charge up the battery once started. What sort of distance would it take to top up the battery from dead? 30 minutes up and down the motorway at say 3k RPM?

This will be the second time I've had a flat. Do batteries recover or should I be looking at a new one? AFAIK it's still the original (1999 Griff)

Cheers,

Dave

[Ballistic Banana]

Now I am no expert Dave, but my understanding is once a Battery is/has gone flat a Couple of times it will never hold the full charge that it was designed for again.
Now I think you can get away with this on smaller vehicles that dont require so much Starting Current, but with the Griffths you might find it struggles.
From what I have read aswell 4 years for the Standard Griffith Battery Life is about average.
We have a fleet of Land Rovers and HGV Unimogs that are 12 and 24v beasts and once the battery goes on them thats it flat every morning.kaputt, have to change them.. (thats normally winter time)

Time to get a battery conditioner, unless its parked out side

Hope that helps.

BB

[pebbledash]

Lead acid batteries hate being "deep discharged" it usualy kills at least one cell, if not the whole lot.

You can check for this, most places that sell batteries have a discharge tester.

The longer the battery is in the flat state the more likley it is to be damaged.

[donatien]

Cheers all, it sounds like even if my battery isn't totally shot now might be a good time to replace it given that it's nearly 6 years old.

Don't have my bible to hand can anyone give me the type/part details?

[simon.b]

I changed mine some time back, do a search you’ll find loads of info.

I couldn’t find one a reasonable price that had the ideal cranking current, so I bought a cheap one to keep me on the road, it didn’t have the vent pipe. That was November 2003 and she still starts fine, I do put it on a trickle charge now and then if she’s stood for any length of time or when were having spot of cold weather.

Cheers,

Simon.

[pebbledash]

donatien said:

Cheers all, it sounds like even if my battery isn't totally shot now might be a good time to replace it given that it's nearly 6 years old. Don't have my bible to hand can anyone give me the type/part details?

IIRC its a type 072...

[kevinday]

Batteries are normally sold in 3 grades, 2 year, 3 year and 4 year. This refers to lifespan, so compare prices between grades, think about how long you will keep the car (forever, because it is a TVR ) and then decide which grade is best for you.

[griffter]

Get the one with the biggest cold start cranking capacity you can. I paid £70 for a sealed unit (no vent pipe needed), 700 cranking amps or something, suitable for all the Range Rovers, Audi V8s etc, big BMW diesels etc. It's basically the biggest capacity battery I could find that would fit in the battery box.

Makes a huge difference to starting, and even stops hesitation when the fans kick in etc.