I have a brand new battery for RadRunner Bikes directly from RAD, still in original packaging.
I replaced a RadRunner 2 stolen bike, and the battery comes with it whether you want it or not.
I still have the battery for the stolen bike, so I am selling the new one for $500 CDN, plus shipping.
The retail price from RAD is $751.45 CDN, including tax.
I live in Ontario, Canada.
Email me if interested.
Tempting.
https://radpowerbikes.ca/collections/replacement-parts/products/rad-battery-pack-1 says:
QuoteExternal Battery Pack is compatible with the RadRunner; RadRunner Plus; RadWagon; RadMini; RadRover 4 (and older); and RadCity 4 (and older).
and
QuoteExternal battery is not compatible with: RadMission, RadRover 6 Plus, and RadCity 5 Plus.
I dunno. If I were in your situation I'd hang onto it.