US Postal Service electric trucks are finally here and drivers love them
US Postal Service electric trucks are finally here and drivers love them
After years of back and forth, USPS has finally put its new electric "NGDV" trucks into service, and drivers say they love the new trucks.
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The one thing I wish they did with these things is make the roof out of solar panels.
These things are going to spend most days sitting outside in direct sunlight. They have nice big flat roofs which makes them pretty perfect to throw on solar panels. You likely would not need much charge infrastructure for the new vehicles and you'd have cut the ownership cost down even more significantly (especially in states with high electrical rates).
Regardless, these things are a no-brainer even without solar on all the vehicles. These are low speed vehicles with dedicated routes and loads of stop/go action. There's not a more clear place to use an EV.
Solan panels on vehicles sounds like a great idea but the physics makes it a stupid gimmick.
You also have to clean them constantly in this application, I imagine.
I guess they could make some kind of windshield wiper for the solar panels.
The top of my car is rarely dirty.
How so? Is it that they aren't efficient enough to be worth the materials it's made from?
Power to weight ratio favors permanent fixed installations. A car roof is far too small to make a useful amount of energy.
Power to weight doesn't matter as we are talking about using a solar panel instead of a roof. There's no added weight. The car will already have inbuilt inverters so the only real weight add is the wiring. But also, this is a postal vehicle which will have large swings in weight anyways. A couple of extra pounds doesn't make a difference here.
Further, this isn't a car, which has a much smaller surface area. These things have about 10 square meters of flat roof. That's a peak output of ~3kW. (realistically, probably closer to 1.5kW average throughout a day) which translates into 12kWh of charge in any given day. Roughly 10% of the battery capacity could be restored daily.
For large vehicles, like delivery vehicles and busses, the math on making the roof out solar panels instead of steel changes.
A roof only needs to be a thin piece of sheet metal, weighing somewhere in the neighborhood of 1-2lbs per square foot
Most solar panels are going to weigh somewhere in the neighborhood of 2-4lbs per square foot. So is likely the panel would weigh 2-4 times as much as just a plain metal roof, plus possibly a metal roof under it and/or additional framing to attach the panels to, so power to weight does absolutely come into play.
That comes in at an additional 400lbs on a vehicle that weighs 6,670 lbs if you assume the maximal weight of the panels and the need for a metal roof anyways. That extra 6% weight just doesn't matter. 6% losses range for 12% free charging seems like a worthy tradeoff to me. (and again, this is the maximal value).
That extra 6% weight just doesn't matter.
LOL weight is incredibly important. Automakers would kill puppies for a 6% weight reduction.
6% weight increase doesn't necessarily mean a 6% efficiency loss, it's not a simple linear relationship like that. Depending on the power of the motor and a few other factors that 6% weight increase could mean a huge hit to efficiency.
It's cheaper to put a light roof on a car, buy the same area of solar cells, set them up to charge a battery, and charge the car off that battery, than it is to buy a custom, toughened, solar cell the area of the roof.
Plus, you don't have to haul around the extra weight at the worst location for weight in a vehicle.