Stopping even for 15 minutes every 60-75 minutes is ideal to maintain comfort, mental awareness and prevent the onset of fatigue. We don't need bigger batteries. The current batteries will do that. We need high power dense batteries and better smaller charging technology.
The current Enerdell cells have a standard 5C charge rate, or full charge in 12 minutes. I believe Dr. Wong from farasis will eventually give the ok for at least 2C charging on the 2016 cells. They are a better chemistry than the 2015 cells and more energy dense and more power dense.
Better charge technology is what needs to improve. And with SiC Mosfets, and/or combining the charging system with an oversized controller system and using one of the three motor phases as the PFC inductor to keep that heat out of the charger casing, and keep the charger/controller cooler and smaller will allow one day to carry 50 kW charging on board. This will be needed as future fast charging can happen from DC fast chargers, using the charge stations as a power source to power the chargers at 400 VDC at their 125 amp limit.
The Zero's are safer, less expensive, less complicated, and more efficient at 116 volts rather than 400. However, since the rest of the industry has adopted 400 volts, getting a direct charge to the batteries will have to go through chargers we carry with us.
If you look at page 4, on the left side under "Electrical Output" you will see the rapidly deploying next generation of CCS chargers will only do 300-460 VDC output.
https://www.chargepoint.com/files/datasheets/ds-cpe100.pdfChargePoint already has a fully functional corridor of these stretching from Mexico to Canada along I-5. However we can use these as a power source if we carry the AC to DC charger with us.
That's the way I see it going. I've done every type of riding and done huge distances. Those who ride more than 1 hour at a time, usually get sore or chaffing and can't end up doing 1000+ miles in a day. Those who are smart, stop every hour for a least a drink of water, to close your eyes for 20 seconds to mentally refresh and to walk to keep the blood circulation going in your legs. This stop can be 10-15 minutes.
If you stop 15 minutes (4C charging) every hour at 70 mph, in a day you can do 1120 miles pretty easy. 1120 is 70 miles, 16 times during the day. There are exactly 16 90 minute intervals each day. 90 minutes is an hour at 70 mph plus 15 minutes at 4C charging, and 5 minutes to get to and from the highway.
So for touring, I don't think batteries need to get that much better. Although I'm sure they will every year or two by a little at a time. But what really needs to happen is charging needs to improve rapidly.