I just went 80km on a charge with heat on, then the low battery warning popped up. But all is not doom and gloom, I got my hands on a cell!
It came from Italy, a company that specializes in conversions and home-brew scooter solutions. It was cheap, and SUPPOSEDLY low mileage.
Part number: 295B9-3NF0B QR 14520 07486
Before I just chuck this one in, it might be wise to capacity test it. Wouldn't be fun at all to put in the hours and end up with similar range.
Specs seem to point towards 0.3C discharge rate, so that's what I'll aim for. Only problem is, I only have 18650 capacity testers that are made for max 10AH batteries... Might be time to invest in some better testing equipment.