Just thought I would share for others who may have a similar problem from time to time. I found myself having to park the Jag or Jaaaaagggggg, outside for an extended period of time and decided to try a solar battery tender. Previously I have had the battery drain to where it would not turn over after sitting for nearly 3 weeks. So I searched and searched. There are plenty on Amazon and eBay but after reading a good number of reviews I settled on this...

Battery Tender 5 Watt 12 Volt Solar Panel Charger

Battery Tender 5 Watt 12 Volt Solar Panel Charger with OBDII connection

As you can see it also comes with a OBDII connection which I used for simplicity. Without using the mounting cups, I just put the panel on the dash in front of a sunshade and plugged it in. After 3 weeks of sitting outside it started right up - no hesitation, no slow starter rotation - just normal key in, turn and crank. Now I did not hook up my volt meter and give it a thorough test, but I do know in the past that sitting for 3 weeks it would not hold enough juice to crank so I am pretty happy with this so far. We will see how it lasts as some of the cheaper off-brands on eBay and Amazon had issues with warping and melting of the panel. This one seems well made and has a 5 year warranty. It also has a built in charger controller with reverse charging protection that's suppose to go into "float" mode and maintain your battery and not overcharge it. I purchased it from the Battery Tender on Amazon for $64.95 but you can also purchase direct from Battery Tender but for some reason it is listed on their site for $113.95? Why I don't.

 

Thanks I think I should get that right away .
my alternator gave up and will be refurbished in the coming week but you never know when they return it.
naturally my 1 1/2 year old batterie was like completely drained so I put in a friends 74 amp only to recharge the 95 amp good size one for 3 days, then putting it back in
a week or so ago. Continue waiting to drive again

 

Why not use a battery tender or charger?

 

Hm
that is what i just explained
I do not have one but will get one to charge the batterie while not using the car waiting for the repair

 

There are plenty for sale at amazon, home improvement stores, and autopart stores.

 

BTW; 5 watt is nothing for ANY car. Our car easily consume 10-15 amps a second when running or 150-200W. Our alternator is rated for 120 Amps BTW or 120*14.4V = ~1700W. 5W is not even a drop in the bucket.

 

My measurement for (parked&locked) current drain averages 36mA, or 0.86Ah/day. Or about 0.5 Watts.
Whether a solar panel is adequate for a trickle charge depends, but in a windscreen it's unlikely to be more than 1/4 of the day and only a fraction of the time at optimum angle. It might do or is better than nothing if there's no access to a power point. Running consumption has nothing to do with it.

I see that solar charger mentioned limits to 15.2v, which seems safe since the car can go to 15.3v according to Jaguar. The green charged light comes on at 12.9v according to the manual, so it has a "regulator" though not a fancy one! I don't think you'll be overcharging the battery lol.

 

Free,
As Chris suggested, you may want to check your parked battery drain. The X350 Jag isn't a battery killer (though some parked cars, like my M3 ,are).

Here's a cheap and easy way of checking:
- Disconnect bat neg terminal (everything electrical turned off; leave trunk open for 30 minutes before procedure)
- Put test lamp between neg cable and battery (eg 12V test lamp..... )
- If the bulb lights, you've got a drain problem (it takes ~ 75 mA to get even a faint glow. Bright is a major drain)
- This is just a quick way of checking things (and a good thing to do before putting an expensive VOM in circuit to actually measure things)

 

For as long as I've owned it I have always had to start it every 3 weeks or I would notice weaker starts. Any longer than that and I risked a possible dead battery. I recently replaced the battery as it was old and would not charge. However, I ran in to the same situation after letting it sit for 4 weeks. Just enough juice to unlock and unfold the mirrors.

No need for a test light as I have multi-meter I can use to check for drain. It's just as quick as a test light but way easier to narrow down the source. Just as a test light simply remove neg cable, touch one lead to neg post and the other to neg battery cable and done. Meter will show drain if there is one (anything over 50mA would be an issue) and then start removing fuses until you see a drop in the drain to find the source. Unfortunately I don't have the time at the moment and with my luck, I can't remember the last time something has been a simple quick fix. However for the time being, my cheap solar fix has alleviated the issue until I can dive deeper into it.