RPM + Battery Power

peter212693 · 25 Mar 2006 at 19:09

Hi all

When I am driving during the day my car sits at just on or just over the 1000 rpm mark, I have my radio and my blowers on sometimes. Now at night when I have them on + my lights it will drop to about 700-800 and the car feels like it does just before it stalls but it will drive fine once I increase the rpm with my accelerator. I have a little thing on my battery and it says it’s charged but probably inaccurate, its 3years + old now.

Is this my problem, an uncharged battery?

SgtTupac · 25 Mar 2006 at 19:10

It drops because you are "loading" the car. Your draining battery power causing the alternator to run more power. its ok

peter212693 · 25 Mar 2006 at 19:11

SgtTupac said:
It drops because you are "loading" the car. Your draining battery power causing the alternator to run more power. its ok

I have not noticed it before only recently, will charging the battery help?

moss · 25 Mar 2006 at 19:14

peter212693 said:
I have not noticed it before only recently, will charging the battery help?

No the alternator should be doing that for you, its probably the alternator or battery on the way out.

peter212693 · 25 Mar 2006 at 19:23

moss said:
No the alternator should be doing that for you, its probably the alternator or battery on the way out.

Which is it most likly to be the battery was bought in 2002 and i dont know about the alternator. The car is "P Reg" so 96-97

SgtTupac · 25 Mar 2006 at 19:30

I take it you got a Multimeter, start your car and check the voltage across the battery, when its running it should be about 14v, when engine is not running it should be around 12v

Dr Who · 25 Mar 2006 at 19:49

if its a fuel injection car (likely) the idle control valve may be faulty

peter212693 · 25 Mar 2006 at 19:50

Dr Who said:
if its a fuel injection car (likely) the idle control valve may be faulty

I take it thats not good

and yes its an injection

-Mike- · 25 Mar 2006 at 19:51

My mates swift does this also, but with lots of draw the alternator/battery at night it will stall if you let it idle. Its fine during the daytime and holds the revs. I'd say get your battery tested and if you have a multi-meter as mentioned check your voltages. It should be able to hold a reasonable figure.

I'm not too sure on my alternator but with lights on, heater, rear demister fog lights and stereo when driving it will hold 14.