Trunk Pannier long enough for RADCity (15 inch) to hold spare battery?

[KenPurcell]

I was just looking for hours today to find a long enough trunk bag to hold the 2018 14AH battery. Not easy. Almost all trunks are 36 cm or shorter. I need 39 cm.

Thanks for any suggestions.

PS. When are the new 2018 batteries available to order?

 

[KenPurcell]

Looks almost perfect. Thanks JayVee