Originally Posted by Scottish Chap

Great post!

Two checks today:
1. 12.59V, then a load test yielded 12.35V.
2. 489 out of (guessed) 650 cold cranking amps without load, with a potential of 12.32V.

Would you guys change this battery? I know there are Gremlins that appear with low voltages.

Originally Posted by ant17

How old is the bat? Mine was 9 and still worked, but I didn't want to get stranded here in the frozen tundra of Chicago.

Originally Posted by Stillwaters

After a few battary/charging issues of my own, I decided to hard wire a battery tender cable to the battery in the trunk of my XK. that way, I don't have to crawl under the rear of the car to clip onto the positive (+) post behind the quarter panel each time I wanted to leave the car on a tender.

Now, the important part. One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged. As a result, the car started shutting down secondary systems in an effort to "save" more critical power requirements.

These days, if I am leaving the XK in the garage for more than even a day or to, I simply open the trunk, connect my tender directly to the cable I pre-installed, close the trunk, turn on the juice, and as they say in my home town of New York City..."FORGET ABOUT IT"..

Originally Posted by dag82

Hello
curious does this statement still stands true?
just purchased battery tender for the XKR and don’t want to install it incorrectly.

"One of the techs on this site told me (and I am now telling you all) DO NOT install the ground side of the tender cable directly onto the negative (-) post of the battery. Instead, wire it to the spare tire hold down post. At first I went right to the ground side of the battery and that somehow "confused" the ECM into thinking the battery was low when it was indeed fully charged."

Originally Posted by Graham

I bought a cheap solar panel car charger and placed it on rear shelf. Wire can be hidden down edge of rear seat and to right hand kick panel. Then add an aftermarket fused cigarette lighter to the main 12 v terminals there and plug in the solar charger. Less than 5 minutes neat and no permanent modification.

I installed this in 2004 on my xj8 which tends to stay parked up for weeks at a time. Prior to the instalation battery went flat over any 2 week park up period and I ruined a OEM three year old battery. The cheap replacement battery never let me down and lasted 7 years until the day my wife accidentally turned the solar panel upside down. Then two weeks later the battery was deeply discharged and not recoverable.

Hence it seems:

A $20 dollar solar panel charger prevents the discharge on parking and possibly saves more than its cost by lengthening the life of the battery even in winter, even in northern latitudes (daylight 8.30am to 4.30pm).