Time for a new battery for my XJR?
Discussion
Hi guys,
I think my battery might be nearing the end of its life.
Recently, I noticed when starting the car from cold (this doesn't happen when restarting the car when it's warm, and has recently been used), it cranks over a little longer than it used to, and then there seems to be a momentary pause in the "cranking" after which it fires up. Also, during this momentary pause (it's half a second or less long) "Trac not available" flashes on the display.
Reading here and on various other forums, most people seem to agree these are signs of a weakening battery.
I checked it with a voltmeter this morning. Measuring it with the ignition fully off, it was showing 11.85V. With the ignition on, lights and radio on, that went down to about 11.35V. I didn't go ahead and start the car, to check what it was when started, and during cranking, because I didn't want to unnecessarily start the engine, when I wasn't planning on going anywhere.
These voltages seem a little low to me.
Do you think it's time to replace it? I don't have a good charger, and I suspect it would cost me close to what a new battery would cost to buy one. Plus, it's a major pain in the a** to be taking the battery out and charging it. Also, the winter has just begun.
Do I have to get an original Jaguar battery, or can I get one from Halfords? Or can you recommend some other place/website, or alternative battery? I can imagine the original from Jaguar would be upwards of £100...
The original is 90Ah and 680 Amps. Also, there's a little hose connected to one side of the battery, no idea what this is, never saw something like that on a battery before. 
Thanks guys.
I think my battery might be nearing the end of its life.
Recently, I noticed when starting the car from cold (this doesn't happen when restarting the car when it's warm, and has recently been used), it cranks over a little longer than it used to, and then there seems to be a momentary pause in the "cranking" after which it fires up. Also, during this momentary pause (it's half a second or less long) "Trac not available" flashes on the display.
Reading here and on various other forums, most people seem to agree these are signs of a weakening battery.
I checked it with a voltmeter this morning. Measuring it with the ignition fully off, it was showing 11.85V. With the ignition on, lights and radio on, that went down to about 11.35V. I didn't go ahead and start the car, to check what it was when started, and during cranking, because I didn't want to unnecessarily start the engine, when I wasn't planning on going anywhere.
These voltages seem a little low to me.
Do you think it's time to replace it? I don't have a good charger, and I suspect it would cost me close to what a new battery would cost to buy one. Plus, it's a major pain in the a** to be taking the battery out and charging it. Also, the winter has just begun.
Do I have to get an original Jaguar battery, or can I get one from Halfords? Or can you recommend some other place/website, or alternative battery? I can imagine the original from Jaguar would be upwards of £100...
The original is 90Ah and 680 Amps. Also, there's a little hose connected to one side of the battery, no idea what this is, never saw something like that on a battery before. 
Thanks guys.
Edited by vladman on Saturday 27th October 12:38
It does sound like it's starting to fail, so take action now as one frosty night will kill it.
It's maybe worth a phonecall to the Jag dealer, i remember someone in the Jag club saying he got a new battery from the dealers at less than Halfords, don't know if it was a special offer tho, but worth asking?
Oh and remember and get a good heavy starter, these cars need a good crank!
It's maybe worth a phonecall to the Jag dealer, i remember someone in the Jag club saying he got a new battery from the dealers at less than Halfords, don't know if it was a special offer tho, but worth asking?
Oh and remember and get a good heavy starter, these cars need a good crank!
vladman said:
vladman said:
bigdavy said:
Oh and remember and get a good heavy starter, these cars need a good crank!
Sorry, being a bit thick, don't understand what you mean here? 
Batteries come with different output levels, my wife's micra will start off anything but my XJ6 needs a HIGH output battery as Jaguars need a lot of starting (cranking) power.
Ringram, Vladmans car is a 6 cylinder engine not a V8 like yours so wouldn't suffer what sounds like a nikasil starting problem.
Guys, my car IS a V8 (supercharged). It's a 2000 XJR.
Ringram, that does sound pretty scary, what happened with your engine? Was it nikasil related? I've had it confirmed to me that my engine is post-nikasil, so should be unaffected by that problem.
I've also now looked at the voltage when starting the car. The lowest it dips to is about 10.25v during cranking, and then it settles around 13.7v when the car's running.
Ringram, that does sound pretty scary, what happened with your engine? Was it nikasil related? I've had it confirmed to me that my engine is post-nikasil, so should be unaffected by that problem.
I've also now looked at the voltage when starting the car. The lowest it dips to is about 10.25v during cranking, and then it settles around 13.7v when the car's running.
Quite likey yes. The day I went to sell it too! Never failed to start before that. But the symptoms were as suggested. Engine spins over fine but wont fire. Basically lack of compression, but it had plenty of power before then so maybe it was just a gremlin.
Sold it off cheap rather that messing about with it.
Sold it off cheap rather that messing about with it.
A fully charged normal car battery should be 12.6 volts (gel cells run around 13.8 to 14.1 volts). If you are fully charging the battery, either with a charger or by driving the vehicle for an hour or so, (less time if you have no accessories on). Then turn on the headlights for 15 seconds to get rid of the surface charge, after you turn it off. If you read less than 12 volts, it probably is dying.
Cars with alot of electronics like a Jaguar can be hard on batteries and need to have good functioning batteries in them. In my experience, Jaguars start to have funny things happen to them electronically when system voltages drop below 10.5 to 10 volts due to the modules not getting the voltage they need.
Cars with alot of electronics like a Jaguar can be hard on batteries and need to have good functioning batteries in them. In my experience, Jaguars start to have funny things happen to them electronically when system voltages drop below 10.5 to 10 volts due to the modules not getting the voltage they need.
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