We all know that one of the biggest problems we have with our cars is the battery, drop a volt and a bit and all sorts of weird , crazy and sometimes heart attack inducing things happen.

Well I may have a solution and I wanna run it by you lot to see if there was anything that I missed.

Two batteries connected in parallel like they do in commercial trucks. Connecting that way would give the same voltage but with more oooopmh and hopefully longevity. The batteries would need to be a matched pair and after jumping the batteries together you would have to connect the positive to the positive on one battery, and ground the negative on the other battery, that should sort out any capacitance issues. I should think the alternator would not need to be changed . The only major issue would be where to put the second battery, later Im gonna pull my trunk and have a gander to see if there is anywhere under the floor , which Im not holding my breath over, the only option will be to get creative. One advantage is that the second battery , where ever it goes , will be on the left hand side of the car which will put that weight over the back wheel, now its all equal. All my Mustangs had two breeze/cinder blocks velcroed either side of the trunk space , but that was to mainly help with the twitchy rear end. But......same idea.

Anyway, if anyone can think up any way that this won't work, or anything I missed.......chirp in.

Thanks......

PS....my gf just walked in and said I should put it on the rear seat "as no-one can f@@@ing sit there anyway"

 

My 2003 SL500 had two batteries. One under the hood to start the car and the second in a compartment under the trunk floor to power the accessories. I still needed a CTEK maintainer connected to the trunk battery or weird stuff would happen…

 

CTEK solved most of my gremlins, as well. I have also gotten into the habit of starting the car with Stuart's method (brake pedal last), which seems to have cleared up the intermittent infotainment resetting issue. Presumably because it spreads the amp draw out instead of everything trying to power up at the same time as the starter is turning. I would be hesitant to add the weight of an extra battery, but that is my 2 cents.

 

Why add a second battery? I'd replace the conventional flooded (wet cell) battery with an AGM battery and a CTEK or similar battery maintainer to keep it fully charged.

That's what I plan to do, as my existing battery is getting weak as evidenced by slow closing of the top with White XKR 's remote top controller and the engine off.

 

The Battery needed for an XK convertible is a large & heavy one. Very awkward & back muscle risky to wrangle into its spot in the back of the trunk (or anywhere in an XK for that matter). I replaced my original Jag battery 6 years ago with a top end Napa, and it has been going strong ever since. Like others, I religiously use my CTEK maintainer. The only issue I had is when this battery drained & I realized it was due to my CTEK connection at the battery terminal working loose. As you noted, Jags & their wiring/electrical systems are something else; I strongly advise against daisy chaining two huge batteries together. Look into CTEK, it does more for your battery than just maintain or recharge. Lastly, having owned Convertibles in the past, I found it best to have the engine running when ever I operate the convertible top…but to each their own on this last bit. Good luck.

 

I have an 07 XK Convertible purchased thus summer. What make and model of trickle charger do you guys recommend for winter storage? I live in Spokane Washington. Also does anyone know where I can find a passenger side hinge plate cover ?

 

@Gearjammer No not the back seat. You want at least some semblance of a firewall between you and a battery as well as ventilation.

If you can't use a CTEK or other maintainer for lack of an outlet somewhere nearby, consider a smaller version of your idea. Carry a portable car jump start battery in your boot like this one:


I've had mine in the boot since 2019. I pull it out the check the voltage and charged it once IIRC.

@Dr. Noodles I use this one and it works very well:

Most on this forum like the CTEK so they can weigh in on model. CTEK is a good brand and I've read Jaguar recommends them as do other luxury brands. I just went a different way.

 

Hi I got a replacement unit from Barratts in the UK. But it is a big job to replace the unit as the whole side panel at the rear seat and the seat belt anchor point has to come out to gain access. If you have access to workshop manual then that is a great help.

 

i was going to post about my battery "solution' a while back but life got in the way. So here it is... the last time I visited my Jag dealership for some minor work, I mentioned the common opinion of needing a trickle charger on the car when not in use. The shop manager said that should not be required and instead he did some sort of re-flash to the car's electronics. I have not need the trickle charger (over a year) and only plug it into the Cteck during winter storage.

Alfred

 

Ha ha, using a battery maintainer might be an issue, 100 feet of extension cord meandering it's way through the car park will go down like a fart in a space suit.

 

yea that was my gf's 'Jag joke' of the week......at least it's shut her up about "wipers standing to attention" on my VDP, but no Im not even considering the back seat......Ill find somewhere .

Im gonna look into that charger.

 

Does anyone have any real life experience with the "Priority Start" product?

 

Yes, I have had great results with the Priority Start device. My wife’s daily driver was a Jaguar S-Type V-8. When it turned 8 years old it started having the phantom battery drain. Batteries had been replaced & Alternator checked; ultimately it was likely a wire somewhere lost enough of its insulation to start grounding itself against metal somewhere. Installation of The Priority Start Device stopped the problem immediately (saving me from having to drive to her workplace every evening to jump start her car). The Priority Start Device connects to the Battery’s Positive terminal with a substantial clamp. It then has a battery sized post for the vehicle’s positive cable to be clamped to it. The Priority Start Device monitors the outgoing charge from the vehicle’s battery. If the battery drains to a predetermined charge level (well above the minimum needed to start the vehicle) the device shuts off outgoing charge. Once the driver enters the car an puts their foot on the brake pedal, The Priority Start Device deactivates and allows the battery to start the car. No more problems after installing this device. We kept the car another 3 years and traded it in for a new XF. I kept the Priority Start Device. Far more cost effective for my to go with this device than to have a mechanic try and find the problem wire.

 

I also had a Priority Start on my old F150. It saved me huge hassle more than once, repeatedly more than once. Worst calamity WOULD have been at the airport, return trip, 3AM on a Sunday, while snowing.
I had to hook up the To-Ground switch because my tail lights didn't pull enough amps, but no biggie. The Priority Start got me home with merely a ten second delay!