Author Topic: Flat Battery, try to charge horn goes off (Read 7680 times)

RoyP · « **on:** December 13, 2023, 12:06:53 PM »

My car would not start this morning, no lights, nothing.
Connected charger, switched on and the horn went off, any ideas what I can do to fix this?
Local garage thinks I may need a new battery.

jazzaro · « **Reply #1 on:** December 13, 2023, 01:47:21 PM »

Checked the horn fuse?

Lord Voltermore · « **Reply #2 on:** December 13, 2023, 02:32:42 PM »

It may just be the cars alarm/ security system detecting an unusual voltage situation as possibly unauthorised tampering. If I disconnected the battery on my corsa the retro fit alarm would activate when I reconnected it .The alarm cancelled when I pressed the unlock button on the key fob.

The garage is partly right in that a battery that discharges might be on its last legs and dont always fully recover. They can also be subject to unusual voltage fluctuations that might cause malfunctions in sophisticated electronics. But an alarm activating is not conclusive proof that the battery is duff. Try disconnecting the battery for charging, preferably using a modern 'smart' charger . These usually have a pulse charger cycle that can restore and renovate a flat battery better than older battery chargers.

fatal · « **Reply #3 on:** December 17, 2023, 09:57:46 PM »

I've not been using my Jazz much lately and as a result the battery has not been up to starting the car in this cold weather. On the three occasions it's failed to start I've used a jump starter, the type that looks like a mobile phone with two short leads attached. On this last occasion I've hooked my battery up to an Optimate 3 battery tender ( i normally have my motorcycle connected to it) for 36 hours. So far so good, I'll see how it is over the next week or so. Might be time for a new battery otherwise

Westy36 · « **Reply #4 on:** December 19, 2023, 02:19:26 PM »

Quote from: fatal on December 17, 2023, 09:57:46 PM

Might be time for a new battery otherwise

I would say the writing is on the wall with that. I would get it replaced asap.

Lord Voltermore · « **Reply #5 on:** December 19, 2023, 02:59:11 PM »

I had to fit a new battery on my corsa. The battery was 12 years old - not a bad innings

And indeed it would still always start the car, first turn of the key. But it started getting fluctuating voltages which did some strange things to the cars electronics ,including sometimes setting off the alarm. It was only when one of these gremlins meant the car didnt always start first time that I learned it lacked the capacity for a second attempt.