Battery Leakage

[Lévon]

My 1979 Porsche has always needed to be kept on a trickle charger, otherwise the battery goes flat after 3 weeks in the garage (2 in the winter). The trickle charger that I've used for past 15 years is a CTEK XS800, but have recently noticed that even this is unable to keep the car fully charged. Even after the car has had a good run and when connected starts off green, the light turns to amber after a few hours.
The previous owner had the later fitted parcel shelf alarm deactivated as it was always going off and was told that this could be a drain. However, I have since accidentally discovered that the siren is functional, and the only thing they disconnected was the sensor to it!
Last month, I had a new battery, a new alternator and regulator fitted and the current drop when measured was less than 0.2A - but am still finding that the trickle charger (designed for small batteries, but intended for maintenance of seasonal storage batteries) cannot keep the battery fully topped up, and the light on the charger is constantly on amber.

Is this battery leakage a common fault in such older models? Does anyone have any suggestions what else I could do? Is it possible that the trickle charger has become faulty and unable to switch off?
Happy for any suggestions.

 

[chris.hevey]

I replaced a battery three years ago as it had died an early death because I was only using the car irregularly. One of the guys in the region explained this was due to it becoming calcified. I bought a ctek xs 4003 to keep it in good condition about a year ago as it does more than simple trickle charging. Too early to tell how long it will make the new battery last but it seems ok, but the remarkable thing is that it appears to have brought the old battery back to life!

 

[dij999]

Your luggage compartment light does go off when you close the lid doesn't it?

I also had a problem with the interior light coming on occasionally while car was standing because of a frayed earth wire to one of the door switches. It intermittently earthed and switched the light on flattening the battery. Took a while to find that.

Dave Jones