I was thinking the other day and wondered how important it is to have the right size battery in your car.

 

Mine is definately too small and I wondered if that affects any of the running of the car.

I know when I'm pulling away the lights will sometimes go a bit dimmer and the blowers will slow down a little.

 

 

What do you think? Is it really important?

that's not your battery, it's your alternator. The battery is only really used for starting the car, or powering stuff when the engine is not running

So you think the alternator is knackered? Just it seems to keep the battery charged enough so it gets me started every day

Are you auto or manual? And why do you think your battery is too small?

your battery is 12v

your alternator starts charging around 700>800rpm @ 14.3v

 

now what u seeing is when you pull off that your dropping the rpm below the alternator threshold

in turn not running the electrics at 14.3v but 12v from the battery so things like your lights and heater fan will

will change a little as these are High Current draw on the system

 

Ideally your battery needs to be around 70amp for Auto .. you could get away with small one but this will effect your Cranking time

The battery is too small for the plate it sits on and not tall enough for the tie downs. Definately too small it physical size at least.

 

The car is a manual conversion - do the auto and manual alternators differ in size or anything?

 

So if the revs are dropping, would this be something else at fault or could the alternator/battery be playing a part in that as generally the revs seem ok... Maybe I just need to rev it higher when I want to pull away.

I get the same from vectra estate when I first pull away. Not had a problem with it though. Car starts first time and I've never had a flat battery (on the vectra that is! lol)

all TT Alternators are the same 90amp output ... NA's are around 70 but doesnt really matter to much

 

check the Spec of the battery .. as size dont means its to small if it dont fit the tray

 

Rev's are dropping is because your letting it when pulling away

Even when I rev quite high the revs still drop a little though. I don't remember that being a problem before lol. Plus when I driver other cars it doesn't seem to happen :-/. Maybe it's just not as obvious

take it to a garage get them to put a load tester on it .. see how good it is

it may be a little down on voltage