Flat battery recharged, keeps clicking on and off

[Rob79]

Hello, I was wondering if anyone could  help please. I have a LS600HL and the Battery went completely dead. I charged it up this weekend and the charger says it is fully charged. Upon reconnecting the horn alarm went off, but I managed to stop it. I got into the car with manual key entry. The dashboard was going crazy. The interior lights are coming on and off. There were a few minutes of very weird activity. 

The situation now is: the Battery in the boot is clicking on and off. I can't start the car. The horn is not sounding, but there is a groan/ creaking coming from under the bonnet, at a similar internal to the horn alarm. 

The main issue seems to be the Battery not providing stable power, but clicking on and off every second. I've disconnected and all is now quiet. 

Does any one have any ideas please?

Thanks, Rob 

[mikeyv]

Not a clue Rob, sorry.

If you have no luck here, and it's a rare car, so you might not, try the facebook group, where there are a couple who own 600s, as well as some Lexus techs.

[Britprius]

If you have a multi meter as a first port of call I would check the Battery voltage under some load. A car headlamp bulb would do nicely. If the Battery is any good you should get a reading well above 12 volts, and ideally around 13.4 volt. A reading of under 12 volts suggests a dud Battery. A reading taken without some load is virtually meaningless. 

John

[Rob79]

Cheers, I may try Facebook. Forgot to mention that is a new main dealer fitted Battery (about 8 months ago)

I don't have a multi meter unfortunately and I know literally nothing about cars! I assume the Battery in the back is the only one and if I wanted to jump start I would use the Battery in the boot?

Thanks, Rob