I need to replace my battery, and I am wondering if there is a good way to maintain power to the car during the process so that I don't have to worry about resetting the radio code and any other electronics that might be affected. I got a radio code from the dealer, but don't want to find out it was the wrong one.


Has anyone done this?

 

You could connect a alternate power source to the battery leads prior to changing the old battery.
Surprised you have a radio code though.

 

I'm also interested in this. I just bought my car and would like to take the battery in to have it checked out. Resetting everything sounds like a chore.

 

I use a portable jump box which I carry on my boat or in my cars for security basis, just in case. Connect the jump box to the battery cables before you disconnect the battery.Rich

 

You have to enter the radio code and run both windows fully down, then fully up. There's no more to it than that. Messing with jump starters and power packs is worth neither the effort nor the potential to short out the positive while you're reaching in to pull the battery.

 

Radio code (if your car uses one), tone controls (station presets stay in memory), windows. Takes 2 mins.

 

You may not need the Radio Code even though a Code Card is supplied. Most U.S. Cars do not need the Code.

 

I was wondering about the same thing. I have seen gizmos at Pep Boys that you plug into your cigarette lighter that supposedly retain settings but do these really work and are they safe?

Doug

 

From memory, I seem to recall reading about cigar lighter-type devices that would plug in and maintain some voltage during battery swaps. Worked with a 9V battery, I believe. Maybe a search under "battery saver" will give you hits. Never used one myself. The alternative is to call a shop that does batteries and ask what they use.

Best of luck. Keep us posted.

 

A trickle charger on the underhood terminals should be enough... the ones us early car guys use to open the trunk if the battery dies (since we have no trunk key).

 

The same key that starts the car opens the trunk.

 

Not on on the early cars. There is no trunk lock.

The XK8 Emblem has a key shaped hole, but the hole goes to solid sheet metal.

 

An old "dumb"charger would work but a more modern "smart"charger would shut off as soon as the battery was disconnected unless it has a supply mode.

 

That is a great tip. I didn't even think about that.

I was the original "Powerwheels Modification Guru" from 15 years ago:



My garage is full of Boxes of dumb 12V wall transformer chargers.

 

I would not use a Battery Charger to maintain the voltage when removing the Battery,

Older chargers can put out a very unfiltered rectified AC waveform with a High Peak Voltage that could damage Electronic Modules.

When the Battery is in the circuit, it will absorb the peaks and keep the voltage from rising to a damaging level.

 

Not sure the cigarette lighter approach will work in the XK8. In my '99, the battery is connected to the lighter socket only when the ignition is on.

 

I'll add my name to the list of those suggesting it's not a good idea to use anything to maintain the supply when replacing the battery. It's not worth the risk of a spike damaging sensitive electronic components and it takes very little time to reset window limits etc.

Get used to it. If you plan on working on the electrics it's almost always safer to disconnect the battery first.

Graham

 

Thanks for the advice. I will tackle it this weekend.

 

Battery change was successful...and a good thing because the vent tube had come off the old battery. New battery has a lot more amps that the old Varta (it was rated at 680).


I went a head and ran jumper cables to the hot post on the fuse box over the left front wheel and grounded to a shock mount bolt. Worked like a dream. Changed the battery and all settings stayed good.

 

ungn - maybe different for non-UK cars, but on my 1997 XK8, the boot (trunk) lock works no problem.
Might be worth double-checking yours not blocked up or something.
Not trying to be clever or facetious, but it's not really likely that Jaguar fitted a keyhole with a blank sheet of metal behind it.