Reisender wrote:
ktmrfs wrote:
wilber1 wrote:
Dang physics.
Energy density of lithium ion battery 0.37 to 0.95 MJ/kg
Energy density of gasoline 44.0 MJ/kg
gas engine efficiency about 25% at best during a drive cycle. electric motors in the high 90-95 %. + the energy recovered during braking.
so that turns tables to about 5 or 10:1 on a weight basis. still and advantage to a gas engine, but not as dramatic as it first seems.
Key is
1) getting charging tine down to about time to fill a gas car 10-15minutes
2) getting infrastructure to support the charging
3) getting power from non hydrocarbon or carbon sources (coal, NG)_ Thermal efficiency of gas turbine power stations is about 60%, better than internal combustion but still not great.
For what it’s worth, on a typical road trip for us our average Supercharger break/stop is around 10 to15 minutes. Maybe 20 minutes for lunch. We don’t stop to charge, we just charge while we are stopped.
yes, that is getting down to about what a typical fuel stop time is when traveling. Now if they had the charging stations at highway rest stops, and a typical charge was 20 minutes or so, it would for us be less time than a fuel stop. rest stop= fuel stop and not on/off the freeway for gas.
While we can go 600+ miles between fuel stops with our truck when not towing we usually stop every 200 miles or so, sometime less at a rest stop and stretch our legs etc. Our car can go almost 500 miles/tank, but again stopping every 2-3 hours at a rest stop and a charge top off would be less overall time than stopping for gas along with rest stops.
