Sure, but keep in mind that 81 nm usage is partly because of the 30min safety. If you double the batteries (another 270lbs) you can increase the range to 200nm, which is somewhat usable.
The main obstacle that prevents progress to this isn't the current technology - it's the FAA rules for what you have to do to certify as an LSA. 270lbs extra isn't a huge extra payload, but added to an LSA it will exceed the LSA gross weight max cap. And the tech itself violates the FAA regulations.
If you get into real GA territory and you take a plane like a Cirrus SR22 and throw out that 430lbs Continental engine and 552lbs of gas and all of the other gas support, you can get yourself a 90kWh battery + inverter + motor instead. That should get you 400nm of range. Sure, it's not the 1200nm you get from the avgas engine (yet), but your TBO will be something insane like... what, 10'000 hours before that electric motor needs to be rebuilt? And your energy price per nm would be peanuts. So now your $180/hr plane suddenly becomes a $30/hr plane, which is hugely appealing.
But manufacturers can't just take a larger airframe and start building an electric version just to see if there is demand - the licensing for that is in the 10's of millions of dollars. So new technology needs to come in from the LSA side where it has a much smaller barrier of entry. But in order to do that, the FAA needs to loosen up on the weight and fuel restrictions first.
Adding 270 lbs to a small plane which only has a 440 lb payload is a big change. You just reduced the plane from two people to a single seater. Kind of a bad deal in a plane intended as a trainer.
With conventional aircraft, like the Crrus SR22, you take off with 552 lbs of fuel, but you land with significantly less. You're plane gets more efficient as you travel. With an electric plane you take off with 500 pounds of batteries and they are still there when you land. Electricity is significantly cheaper than Avgas, which is more expensive than gasoline for cars, so the cost per nm would be cheaper, that's true. The second article above talks about the initial use for electric planes being as trainers, which don't need long ranges and for a flight school, it's probably OK if the plane sits for an hour between flights as the instructor can check out the next student on the ground while the plane is charging.
I was an engineer at Boeing back in the late 80s and early 90s. I'm an electrical engineer and my group was involved in doing engineering test on the avionics for commercial aircraft. However at all levels of an airplane's design, there is a constant focus on making things as light as possible. Shaving even a couple of pounds off a part is favored, save a hundred pounds and you're a hero. Even in the electronics side of things there is a constant push to save weight.
One major factor in range is the fact the plane gets lighter the longer it flies. If the weight of the fuel stays constant, that's going to cut into the range in a rather dramatic way. I don't think you'd see 400nm from 552 lbs of batteries, which would be about 60-65 KWh of batteries. 90KWh of batteries is about 750 lbs. The Model S also has about 250 lbs of non-battery material in the battery pack such as the structure and internal partitions. As the weight of the batteries goes up, you quickly start reaching the point of diminishing returns.
You may be able to save a little weigh with a 90 KWh aviation pack by eliminating the armor the Model S pack carries, but if you make it too thin, you would be vulnerable to bird strikes. You also have to consider where you are carrying the batteries and need to build the structure of the plane to support them. If the batteries are in the wings, the wings may need to be reinforced to carry the batteries which are probably denser than fuel which has a density of 0.72. Li-Ion batteries have a density of 2.1, just about 3X avgas. Reinforced wings adds weight to the plane, which reduces range and performance.
The engineering trade offs with land vehicles are a lot more forgiving than with planes. The Physics bites you in the backside at every turn.
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