A few weeks ago the alarm on my car started going off for no reason whatsoever.....

 

A week later the AA came out tested the alternator which was charging at 14.4 said that was ok but the battery was not holding the charge.

 

Went to Nissan asked for a new one as mine is under warranty who told me to bring the car in they would test it overnight.....how could i as the battery was ***ked.

 

Anyway they let me have a new one but one of the parts guys said 14.4 was charging too high although i thought this was fine????

 

All seemed well then for no reason again alarm starts going off which is now does after about 3/4 hour.....re-set it and it does the same....

 

Could it be an inttermitant fault on the alternator or could the battery be another knackered one?

 

If the car has been standing for a week shouldn't the battery hold it's charge?

 

Should it show 12v or higher.

 

A real head scratcher now any advice greatly appreciated.....

Anyone???

Anyone???

14.4V is only 0.4 too high, so I don’t think that this is an issue.

 

When it’s not being charged, the battery's maximum voltage will be 12 Volts

 

A week does seem short, as many people do two weeks on holiday with the car at the airport etc without problems, but you need to look at the alarms load when set.

 

If it is high then the alarm can eventually flatten the battery, and depending on the alarm type, it can see this as a fault and alarm!

 

Most quality alarms should have very low load and would be looking for sudden change (boot light coming on etc) and not a gradual reduction in voltage.

 

Is there anything else that could be left on during the week and be draining the battery?

Don't think so, i see your point about the sudden drop in voltage though it does make sense.

 

I guess something could be shorting out and causing a drop but buggered if i know what it is????