Jaguar Repair: My 1985 XJ6, deep cycle battery, gm diesel

Question
Howard,

Ok, I have resisted, but my XJ6 is exhibiting symptoms much like those that cause you to suggest a deep cycle battery. It spins and spins with no start on a seemingly strong battery, but after a few minutes on a charger, with the charger still connected, it'll crank right up. I have been looking online at some of my options at our Tennessee market auto parts outlets and am concerned about a few things before I make a purchase. I see varying ratings of cranking amps and cold cranking amps. I know what this all means, but do you have a recommendation as to minimum requirement? Also, I see in dimensional specs that these batteries, I assume due to top posts, are a bit taller than my side post. I have no issue refitting new cables, but is there a clearance issue with the hood? Should I add insulating material to the underside of the hood to prevent shorts? Do you have a photo of (maybe yours) with this setup?

Thanks!

Answer
Hi Michael,

I would not change to a top post battery, there are deep charge batteries with the original side post. Most auto prats stores list the correct battery for the Series III Jag as a deep charge side post battery (diesel). Each time I get one for a series III, it always fits the original battery hold down too. I don't remember the number but as best as I can remember that battery also fits a GM Diesel of some kind.

I will look at mine tomorrow and let you know the battery number as I have two series III cars.

If your battery is a standard battery the test is to just charge up your battery and charge up a jumper battery and try to start on your battery alone and if it does not start, connect up the jumper just like you have a low battery and are getting a jump off of someone else. With both batteries connected, if it starts right up, that is a classic example of the need for a deep charge battery. Note that after a deep charge battery gets old and still spins the engine over fast but does not start and a jumper makes it start then you need a new deep charge battery.

The old deep charge battery can be used in other brands of car for as many as several years. I used to get the old deep charge batteries from the local Jaguar dealer for other cars I use to have including an MG and they usually lasted another few years so I never had to buy batteries for a Dodge van and my MG as I had a steady supply of these used batteries out of series III cars. I did have to buy new ones for my series III though.

Howard