Last Friday, I got a turtle light on my 2002 Prius (which has less than 139,000 miles on it but which is nearly 21 years old with the original hybrid battery). I was in San Francisco at the time and decided to drive to Luscious Garage to get it checked out, and noticed that the car felt sluggish at times. (I had also noticed for a few months that the hybrid battery seemed to jump from nearly discharged to full very quickly.) The LG mechanic ran a test, which did find that the existing hybrid battery was discharging more quickly compared to a new battery. LG offers a 5 year warranty on a new hybrid battery, even though they simply get this from Toyota, so their warranty is a lot better than Toyota’s is. (In August, my insurance had paid to replace the stolen catalytic converter and I paid for a shield over it; the CC is also protected by some welded curved iron rods over the visible end. I *hope* that this new protection is good enough to deter thieves. I also took the Prius to a hybrid mechanic about 6 weeks ago, who thought the car was otherwise in pretty good shape.) I have an appointment tomorrow (Thursday) to replace the hybrid battery as I want to be able to drive long distances with the car and don’t want to risk the current battery failing while I’m on the road. 1) I’ve noticed that my mpg has been dropping down to about 35 mpg. Will replacing the hybrid battery improve that, or is there anything else I should do? 2) Since the current hybrid battery is still functioning, I’ve wondered if it can be repurposed. Any suggestions?