Called Interstate tech support today. The Interstate AGM battery is MTP-49/H8A (the A designates AGM)
This is the one I am ordering for my XK

Vince
Note: According to Interstate, this is an older part number. The New number is MT5-49/H8

 

Fantastic, thanks!

 

Christ, this battery retails at $300!?? At that price I might as well let the dealer do it!

 

My buddy at Firestone quoted me $210. Should be here next week, so I'll know if he got me the right battery then!

-Vince

 

Yup $209 +tax
Battery actually says MTP-49/H8 (no "A" on the end) But clearly says AGM below the number.


Will install tomorrow!

V
Note: This posted part number was in error. The battery I received is MT5-49/H8, which according to Interstate is the same as the MTP-49/H8A. The MT5 is the newer part number.

 

How did it go? Does anyone with a convertible know if after replacing the battery it is necessary to re-calibrate the convertible top?

 

You will need to reset the windows. If the top does not operate, you will need to manually fold it, which effectively resets it. There is no other calibration.

 

I just replaced the original OEM battery in my 2008 XK convertible.
Probably the most inconvenient battery install I've ever done - it's really buried in there !
I put in an Interstate MTP93: I would have preferred an AGM, but that had to be ordered, and this one was available off-the-shelf for around $130.

I must have had the terminals disconnected for 20 mins or so, but the seat position and radio memories were retained. I did have to reset both the window positions and the clock.
The convertible top was unaffected: according to the manual its only an issue if power fails during operation.

And I really don't like the look of those + and - 'jump start' battery posts in the trunk....so I recommend connecting a battery charge lead to the existing threaded studs on the battery leads. I used:
- Battery Tender Ring Terminal harness with fused plug
(Amazon

- Battery Tender 25ft extension cable (also available in 12.5 ft)
(Amazon
The Ring terminal harness attaches to the threaded studs on the battery leads with 2 * M8 (metric 8mm) nuts. It has a 7.5A in-line fuse and about 2ft of wire. It plugs into the 25ft extension, and that easily reaches my charger. The wire easily passes under the closed trunk lid, and had protective caps to insulate the terminals
I keep the excess wire coiled in the spare wheel well.

With this lot, I hope to keep Joseph Lucas, the Prince of Darkness, at bay !!

 

I have the coupe so advice is best from another convert owner.

For the Coupe, the swap was a piece of cake. 10mm socket on a speed handle and a flat blade screwdriver were the only tools needed!

1. Disconnect Negative terminal (10mm).
2. Disconnect Positive terminal (10mm).
3. Detach harness using flat blade screwdriver
4 and 5. Remove battery retaining plate (10mm x2) and swing aside.

Battery simply slides out, new one slides in, and reassemble.

Vince

 

This should be a sticky!

I take it there's no vents to hook up?

 

[QUOTE=amcdonal86;674266
I take it there's no vents to hook up?[/QUOTE]

Nope, I tucked the vent tubing behind the new battery, making sure not to pinch it.


Vince

 

Any idea how the OEM battery compares? The OEM battery is $200.

 

Nevermind, I just found a place that has a MTP-49/H8A in stock! I will pick it up tomorrow!

Any idea if I can just store it in my trunk for a few days until I can install it? It is a sealed battery, right?

 

OK, I got the MTP-49/H8. Mine doesn't say AGM anywhere, but it doesn't appear to have any vent tubes or anything, so I'm guessing it's sealed.

 

The jpg below came from INTERSTATE BATTERIES site, so I assume they mean what they say about your Mega-Tron Plus battery.

Second jpg is off the Gaudin Jaguar site. Seems a reasonable price for a battery IF you didn't have to ship it.

 

If it does not say AGM, I suspect it is not.

You should go back and get the vent kit and return it if they do not have it. An unvented wet cell battery in the middle of the sealed trunk is not a good idea.

 

I installed an Interstate MTP93 - definitely a flooded-cell battery (ie not an AGM). It has 2 long vent-caps that don't look easily removed...
The vent is pretty obvious - its an oblong hole centally-located on one edge of the battery top. I had to use a piece of shrink-wrap tube to connect it ro the Jag vent hose.

Also: there's several Factory 'Special Service Messages' out concerning loose/badly-fitted battery terminals. It looks like they've had reports or warrantee claims in the past...
See attached - basically the terminals are tapered, and they suggest you need to tap the connectors down firmly.

 

For a while now, rscultho has been advocating installing an AGM battery and CleverName came up with the Interstate model MTP 49h8a. My thanks to both of you.

Had that battery installed last week and the touchscreen is happy again. Now, instead of waiting 5 - 10 seconds and wondering if it would work, the screen comes on immediately. This is my third Interstate battery in a year but the first AGM one. The other two batteries, when new, also brought the screen up quickly but that lasted only a few months. Hopefully the AGM will take care of the problem.

Kudos to Interstate as I received full credit for the old battery even though there really was nothing wrong with it. This is the second time they've done that.

I'm convinced that most of the electrical gremlins are caused by the battery.

 

I am proud to report that I have installed the MTP49-H8 (it says H8A on my invoice, but H8 on the battery itself). The shop that sold it to me seemed very knowledgeable about the batteries and said that it was indeed a sealed battery.

Luckily for me, the previous battery in the car was also a MTP49-H8, and already had the appropriate vent adapter, which I hooked up easily.

The install went relatively smoothly. The instructions provided by CleverName for the coupe also work for the convertible, with one exception: the convertible, at least the XKR, has a structural cross-member right in front of where the battery would slide out. This is easily overcome by unbolting the brace's four 10mm bolts. Also, my car had a side clamp holding down the base of the battery. Loosening this allowed the battery to slide out with ease.

After replacing the battery, the car started right up, but was running extremely rough. Idle was cycling up and down by 1000 rpm in a cyclical fashion, and when I put it in drive the first time it almost stalled. I think this is because it is relearning everything as all the adaptations are cleared. I noticed throttle tip in is different now, and the shift points are different, too. Also the exhaust seems to sound different--a little more throaty. It might be in my head, but who knows.

Before reassembling the interior, I tried to put the top down, but only the rear windows would go down. OH NO! I thought I would have to recalibrate the whole top. It turns out that you need to have that pesky luggage cover in place in the trunk before you can put the top down. Who knew the car was smart enough to be able to detect that!

Another thing I definitely noticed was before, when starting the car (especially when cold), the Jaguar logo would stay on for 5-10 seconds before showing the main screen. With the new battery, after hitting the start button, you don't see the Jaguar logo at all--the home screen comes on instantly. I had a few occasions previously where my home screen would never come on at all, and I think the battery was the culprit.

And the weird thing where it wouldn't do rev-matching downshifts when I had the seat heaters on (I'm assuming high electrical load) until I restarted is fixed now, it appears. It feels like a whole new car now!

 

Dang it, now that I think about it, you're right. I think I got tricked and sold the non-AGM version of the battery. It is white with a black top and no marking on the sides. But the shop charged me for an H8A!

I think it will be fine since it is vented and I did hook the vent up, but I'm annoyed that I only saved maybe $10 over what the dealer would've charged for an OEM battery.

I will try an AGM battery next time!