I got a good deal on "46B24R 12V 46Ah 650A Lithium Iron Phosphate Battery LiFePO4 for Auto Car + BMS" from ebay. Took a bit to receive it, and it seems that seller is clueless about batteries and have wrong pictures of other 40B19L battery with correct terminal positions for the Leaf. The minus is my 46B24R has incorrect terminal positions, so it is causing some misalignment of terminals to get it installed, the plus was a bargain price of $300 delivered. You can buy correct 46B24L for > $365. 46B24[R/L] are perfect exact fit for Leaf. Both would fit, but 46B24L would be complete perfection. BTW, neither 46B24L nor 46B24R listing have a photo showing where is + or - terminals, this is the way seller took care of wrong pictures of the "right battery type" in the 46B24R listing, lol. All pictures in 46B24R listings are wrong - those are from "L" type
OPTIMA 51R: 238.76 x 129.54 x 223.52 mm
Li-po 46B24R/L: 237 x 127 x 221 mm
With original battery I was getting ~ 12.3 V in the morning, with LiFePO4 upgrade I am getting 13.35V in the morning.
Also, those batteries have 10 Ah emergency battery, so in case your main battery was completely discharged (< 8V), you can activate emergency battery with switch on the battery and "jump start" your car. I used to carry 12V Lithium emergency start kit, I wouldn't need to carry it in my Leaf with new battery.