41 ms·

How about a smaller battery, but put trolleybus power lines above the road? This is pretty much the only realistic way large vehicles will function as electric.

Kirby64 3y ago
Why would that be the only realistic way? Larger vehicles have more space for more battery capacity, and for stuff like school buses they don’t tend to go super far distances. I don’t know why it’d be a problem. The 300mi seems excessive honestly.
- Aerroon 3y ago
  It's not an issue of space, but one of mass. Tesla's newest batteries are supposedly around 270-300 Wh/kg. 5 tons of these batteries would give you 1500 kWh of energy. Compare this to diesel that has an energy density of 12,640 Wh/kg. Diesel engines are less efficient, but you would still save multiple extra tons in weight for the same distance traveled, which would increase your distance traveled further. Electric buses do work, but the more batteries you cram in there the more extra weight you have to pull around at all times.
  - Kirby64 3y ago
    I fail to see the issue here. School buses have ample space underneath them to store the batteries. Sure you have to account for the extra weight, but just like electric cars the efficiency of the electric motor in a bus is plenty to overcome the difference in power density of the 'fuel' source. Also, given school buses tend to do a lot of stop-and-go, and travel at lower speeds, this is essentially the ideal conditions for an EV.
- RetroTechie 3y ago
  > The 300mi seems excessive honestly. Indeed. Are schoolbuses doing multi-100 mile trips on their route? If so, those kids spend like >1h one-way (so >2h every weekday) riding in schoolbus? Ok. I understand the benefit of shallow (dis)charge cycles. Maybe some extra flexibility in when to charge. Or double as a mobile power source on a school outing. But if not that, it's just extra weight hauled around. And thus, decreasing efficiency. Not to mention cost / environmental footprint of an oversized battery.
  - snypher 3y ago
    It says in the article most routes are 80 miles on the high end but some are 100+ miles with one test on a 147 mile one way route. Edit: and the transportation director doesn't like seeing you come home with an 'empty tank', plus buffer for running heat and a/c during an unplanned stoppage.

Kirby64 3y ago

Why would that be the only realistic way? Larger vehicles have more space for more battery capacity, and for stuff like school buses they don’t tend to go super far distances. I don’t know why it’d be a problem. The 300mi seems excessive honestly.

Aerroon 3y ago
It's not an issue of space, but one of mass. Tesla's newest batteries are supposedly around 270-300 Wh/kg. 5 tons of these batteries would give you 1500 kWh of energy. Compare this to diesel that has an energy density of 12,640 Wh/kg. Diesel engines are less efficient, but you would still save multiple extra tons in weight for the same distance traveled, which would increase your distance traveled further. Electric buses do work, but the more batteries you cram in there the more extra weight you have to pull around at all times.
- Kirby64 3y ago
  I fail to see the issue here. School buses have ample space underneath them to store the batteries. Sure you have to account for the extra weight, but just like electric cars the efficiency of the electric motor in a bus is plenty to overcome the difference in power density of the 'fuel' source. Also, given school buses tend to do a lot of stop-and-go, and travel at lower speeds, this is essentially the ideal conditions for an EV.
RetroTechie 3y ago
> The 300mi seems excessive honestly. Indeed. Are schoolbuses doing multi-100 mile trips on their route? If so, those kids spend like >1h one-way (so >2h every weekday) riding in schoolbus? Ok. I understand the benefit of shallow (dis)charge cycles. Maybe some extra flexibility in when to charge. Or double as a mobile power source on a school outing. But if not that, it's just extra weight hauled around. And thus, decreasing efficiency. Not to mention cost / environmental footprint of an oversized battery.
- snypher 3y ago
  It says in the article most routes are 80 miles on the high end but some are 100+ miles with one test on a 147 mile one way route. Edit: and the transportation director doesn't like seeing you come home with an 'empty tank', plus buffer for running heat and a/c during an unplanned stoppage.