Re: The battery is only one part of the problem
Your math may be right, but your presumptions are wrong.
How far do you drive on that 40L tank?
Over how many days?
When going from a gasoline/diesel-based vehicle to an electric you also change refill/recharge patterns from 'Fill when near empty' to 'recharge when parking'.
Also, you assume that an electric uses the same amount of energy as the equivalent size gas-guzzler.
That said, most electrics today are poorly designed crap only manufactured to keep the greens at bay.
You have a 'mostly stock' vehicle with a big Electric motor, a gearbox, and even a differential and axles in it.
That's a lot of heavy junk that steals power.
The best way to design it would be with 2 or 4 smaller electric motors placed in the wheelhubs.
The only problem then is that you'd need a slightly more advanced motor controller...
A bonus is that it makes it much easier to implement regenerative braking.
The Hybrids out on the road today?
With gas-guzzler engines almost as big as the 'normal' version cars, a big electric motor and a heavy lump of parts to make them work together?
Also a disgrace of engineering.
They need to drop that crap and go directly to the 'Extended Range EV', with a small motor to continuously recharge batteries and a set of electrics for propulsion.
A small gasoline engine optimised to drive a generator is much more efficient than todays car engines that are built to 'perform over a wide range of speeds'.
Also, the generator doesn't even have to deliver enough power to replenish what the car uses at 'cruise', much less what it uses when accelerating.
It just needs to keep the batteries from draining completely before you get to your goal. And any time you stop for a red light, to do a number 1, or to get something to eat, the little engine that could will still be busy recharging the batteries. (Unless you stop at an IKEA or other place that has charging stations of course... )