I’m not a Sams Club member, and as mentioned, Costco doesn’t have anything. We’ve been nursing the MotorCraft battery along for a few months now, occasionally having to throw a trickle charger on it when it starts to display the infamous “shutting down to preserve battery” messages. All kludgy hacks must come to an end...
I went to AutoZone last night, when systems started doing things too weird for my wife. (Too weird for me, actually -- an electrical engineer, and way too disconcerting for her!) Their website said they had 2 batteries for the FFE-T in stock (though not an AGM), so it seemed like a good enough option. They brought out one, a T4, and I knew it wouldn’t fit. I asked if they’d install it, and they declined, saying it was corporate policy not to do swaps on hybrids! (?) I asked if they had a socket set I could borrow, and they were happy to oblige me.
I pulled the old battery, and sure enough, their model was like an inch or more too short, way too small to be locked securely in the tray. The sales guy said that my battery looked like an H5, and that they did have that in an AGM.
Long story short, 20 minutes later my new Duralast Platinum H5-AGM battery with 3 year warranty was in the trunk and the Energi was good to go. CCA's are 680, up from the 590 on the MotorCraft.
Two notes:
The hold down strap barely fits, as the H5 is a bit taller than the MotorCraft. A little fiddling and I was able to get the two straps to interlock.
The door over the battery compartment has an odd piece of plastic that looks like a clip sticking out of it that blocked latching the door correctly. I snipped off the lower part of the clip and it fit perfectly (see linked pics for the before and after).
Because I had to install the battery myself, the sales guy gave me 10% off the price; nice guy. YMMV.
Photos available on my iCloud "Car Stuff" album.