HV Battery Swap

Well, it finally happened. My HV battery quit on me. I bought my Gen 2 used at 131,000 and it ran so well I didn't even think about the possibility of the battery failing. A few days ago the battery starting fluctuating like crazy. I` figured something was starting to go wrong, so I researched replacement options. And what do ya know, the next day I get the red triangle of death. I got a bluetooth OBD reader (super handy by the way) and verified that the battery needed changing.

I looked into every option. Greenbean, Greentec, replacing cells, finding one on Ebay, and the dealer route. I ultimately went with the dealer, only because I wanted the security of having a new battery in there. Sure, you are at the mercy of their prices, but a new battery is great peace of mind for me.

So here is my question: will I see a big change in mpg with the new battery? Does the mpg in a slowly dying HV battery drop over time, or is it a sharp drop in a month? It felt like I had lost good mileage over the past few months, but I chalked it up to winter time conditions. I'm hoping to get back to mid 40's, but I want to hear people's experiences after putting in a new HV battery.