Xc90 2.4d 2003 low battery
 

Hi. Hi have a 03 2.4d xc90. The dash keeps telling me i have a low battery. This happens if my lights are on or just today, when the ac is going for it trying to cool the car down.

I correct it by going a speed suitable for 2nd or 3rd gear, and get the revs up. The lights then get brighter or, today the ac gets load and cold.
Happens nearly every start if lights are needed or it is hot in the car. Does anyone know what might be causing this. It had a new battery last November and alternator about 1.5 years ago.

Any thoughts are welcome.
Thanks
David

If the lights are getting brighter when you rev your engine then something is wrong with the alternator.
A normal alternator puts out a steady 14.4V from about 800 RPM upwards
And it is impossible to see any variation in any bulb brightness from 800 RPM upwards

So get it checked.

No its not like that. When the lights are dime they stay that way. Until i give some revs. Once the lights ard bright they stay bright.
Any ideas. Getting alternator checked tomorrow.

You definitely have a battery and charging system problem.
Do not be surprised if the alternator and/or battery have failed and need to be replaced.