Tell them that you are looking at another Leaf for that price, older but 11 bars. Then say that this one is closer and a little newer, though, and offer $11k. Be offhand about it, and act noncommittal. Say that the offer is for a couple of hours only, and that you'll look at the other car out of town if it's turned down. Again, act the very opposite of desperate or eager. Or, you can be completely honest, and say that you like the car but not the battery. Say that $11k is all you will spend in that situation, and again, make the offer time sensitive. Not immediate, but no more than one day.
Brilliant Silver 2021 Leaf SV40 W/ Pro Pilot & Protection
2009 Vectrix VX-1 W/18 Leaf modules, & 2 lithium E-bicycles.
BAFX OBDII Dongle
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.