So my battery died. I got over 7 years from it and after leaving the car sit for a month and a half it was dead and after charging overnight the specific gravity is still very low but it starts the car. Maybe not tomorrow though. I am not complaining but the previous battery was replaced by Jaguar and they used a Jaguar 90 amp T8-90J battery. So in looking for a replacement I did a search for that battery and could not find any but I found a number of H8 batteries that list as made for the vehicle. While I believe they would work fine I wondered what the actual battery replacement that the manufacturer calls for, a T8 or H8 and for that matter what is the difference between the two, they both vent outside and look about the same. Not a big deal just wondered if I could get some information from a battery expert on the forum.

 

I always use a H8 in my wife's 2000 XK8 and my 2007 XK from WalMart with free install too. Never heard of a T8!!

Hope this helps, Adrian

 

I found the difference, The H8 is just a little taller than th T8. Don't know that this works but I left the battery charger on for the last 4 days at 4-5 amps and the specific gravity slowly came up the good level on a hydrometer. After removing the charger the voltage slowly dropped from 13.4 to 12.8 and seems to be stable there. I did this two years ago with another battery and its still running in one of my cars that I rarely used. I will see what happens with this and make sure my AAA is up to date.

 

Definitely an H8. Several different opinions about AGM vs Lead Acid for our cars, but I've had good service out of my Champion H8-900CH AGM battery from Pep Boys. Bought it online with a seasonal discount and they installed it for free. Good reading here: https://www.repairsmith.com/i/blog/agm-vs-lead-acid/

 

Does it matter that the charging system was set up for flooded wet cells? Is anything needed to be changed? I thought that AGM needed a different charging dynamic, I know that the charger in my boat has different settings for an agm battery.

 

I use a Varta battery now, it was pretty cheap but it does the job very well.

 

True, charging dynamics are different between the two batteries, but I haven't had a problem out of mine. I keep it on a monitor/trickle charger when parked haven't had any trouble out of it in 4.5 years, a rarity given the summer heat of Las Vegas. Would be good to hear opinions/experiences from other Forum members...

 

I agree that AGM is the way to go if you can score a good deal. I have a Bosch AGM in my wife's 2006 XK8 and a Champion AGM in my 2013 Subaru Outback 3.6R. Both came from Pep Boys....

 

My Jaguar mechanic installed an AGM - that’s endorsement from an expert as far as I’m concerned.

 

I’ve got 3.5 years and about 60,000 miles worth of using the starter, lights, etc on my AGM battery. I sourced it from a NAPA parts store.

I keep the car on a Delran Battery Tender + when it is parked overnight or longer. Actually I can’t recall the last time the car sat unused for a 24 hr. period.

Z

 

So that was back on August 2. I left the car in my driveway and went to my summer home and returned today. I opened the door and the window retracted the 1/4 inch or so that its supposed to, a sure sign the battery is charged and closing the door it returned to fully closed. Put the key in and it turned over perfectly. So for what its worth, this is the second time I have taken a very old dead battery and brought it back. This one was 7 years old. I doubt many people know that you can do this. I would not trust it with a boat or if you live in the woods but as long as you have free towing as a back up its worth trying. This battery initially rated completely dead even after trying to recharge overnight.