I've read many a thread by members complaining about dead or weak batterys and the problems this can cause. Jan 18th I went in for knee replacement surgery. I knew my daily driven 101K '98 XK8 conv. would be idle for a while. I parked across the street from my town house. Turned everything off including radio, heater, and auto headlights. Put a brand new $75 ebay cover on her and let her sit. After 30 days of a pretty mild winter with temp. staying around 30-40 daytime and 20-30 nighttime, I was given the OK to drive so the cover came off. I tried using the fob to unlock the doors. Nothing. Tried locking the doors. Nothing. Tried the fob to open the trunk. Nothing. Figured a dead or very weak battery. Opened the trunk with the key getting ready to put the charger on. A soon as the trunk popped up the security system started making it's little chirps prior to the alarm going off. Starting pressing fob buttons to turn off alarm and I heard the doors unlock. Put key in ignition, turned on and checked that the guage showed 9-10 volts. Gave it a shot. Baby started right up without a stumble. Let the engine charge the battery for while. Reset window. Took a slow drive around the developement to get the flat spots out of the tires. She's good to go. I believe 1 month is the max will ever leave the car without it running. Jack

 

She was just trying to show how disappointed she is at being left alone for weeks without any attention. My wife is like that.

 

My 2001 XK8 sits a lot in the winter too. I learned the hard way by having the car towed into the dealer some years ago to put in a new battery. Now I put a float charger, battery tender, to keep the level up to semi-normal.

On one occasion it took almost five days to fully charge that massive trunk battery. Those can cost $200 if bought through the dealer by the way. So avoid that if you can.

 

+1

My Jaguar is used over the winter and it then spends two to three months garaged during the summer. On the older straight six engines cars, XJ40 and X300, this wasn't a problem but as the electrics became more complex with the V8 cars, there's more in the security system draining power all the time.

I found around three weeks is the limit for everything to function normally and, as Jack says, by one month to six weeks disarming the security system can become difficult.

I now leave a CTEK XS7000 battery charger connected in conditioning mode which solves the problem. Not an option for anyone who has to park on the street and I know some have expressed concerns over fire risk but it allows the car to be left locked in a locked garage with the security system set.

Graham