They are obligated to replace my loss with something roughly equivalent. If you have a 2012 ICE that just had a brand new upgraded engine installed and you can prove it, they can not just calculate your loss based on the original equipment - that's not what was lost. When I got the upgraded battery I even asked them if that change in value would change my premium and I was told it would not. I just needed to make sure it was documented and I had the dealership paperwork for the upgrade.
Ignoring the actual cost/value of the battery, what I lost was a 2012 body that had a 1 year old 115 mile battery and not a 5 year old 60 mile battery (Capacity was way down on that old pack).
So when they realized that my car was effectively a 2017 without the fast charge option, suddenly the repairs weren't "too expensive". They had to reach out to the dealer to ask about what that pack would cost to put in a 2012 and that was that.
2012 Candy Blue FFE, 100K+ Miles
33.5kWh battery pack, 26.4kWh EtE
40A+ L2, CHAdeMO, CCS pending