48V14ah Reention Eel Pro Upgrade

[TonyEbike]

I have a Ride1up Lmt'd ebike with a 48V 14ah battery (672WH) and I'm only getting 30 miles to a charge. At approx. 26.5 miles my computer display goes into the red at 44V. Does anyone know if there are larger capacity batteries that will fit in this form factor?
Thanks,
-T