Compare a battery to a tank of diesel in both cost effectiveness and simplicity. When in war, I wouldn't want to be worrying about a wire coming loose or needing to recharge if I need to go up a steep hillside...

A quarter of the Tesla's weight is batteries. What proportion of the Abraham's tank is diesel?

The energy density of hydrocarbon fuels is 20-50X that of even the best current battery technology. Even if you are using electric vehicles, what is powering the generators that charge them? (Hint: @ 80% of electrical energy production is via thermal (coal) generators).

Why bother about emissions when the destruction engendered by the war itself will release more warming/polluting agents that the fuel used by the tanks? Setting a building afire, opening up used water pipes, destroying industrial buildings (setting all their chemicals free), etc... are a major environment hazard and yet still done, so obviously armies have other priorities.

With sufficiently extensive slaughter (and the right propagandistic slant <-- very important!!) warfare can be painted with a carbon-negative brush (possibly even if using crude carbon-positive war machines). As was done to Genghis Khan's Mongol invasion by Mother Nature Network. ;-) (Note: Other media put those figures in a more realistic context.)

@MatthieuM. why bother catching a thief when you cannot remove all crime from the world ? :)

A Tesla S weighs less than 5000 pounds, while the Abrams weighs over 136,000 pounds. Double engines and batteries arent going to come close to the same effective range, simply because the weight is 27X greater. You are going to need massive improvements in battery tech first.

@BrianDHall we are talking about taking the patents and modify it, for use in a future-tech tank. You also need to have a large battery for the plasma/laser/rail/coil gun.

@magic-mouse Right, but my point is that's part of the comparison between engine power and range that was left out - and it shows that battery power of Teslas don't come close to powering a modern battle tank. You'll need to completely reimagine everything about the tank, including the armor and its operational role,because it's just too heavy and batteries a aren't good enough today.

Your next problem will be zero emission explosions...

The other thing about zero-emissions technologies... they're not actually zero-emissions. OK, so your battery-powered car doesn't have any carbon emissions... but the power plant that provides power to the electrical grid used to charge the battery does. "Zero-emissions" technologies just move the emissions, they don't eliminate them.

There is quite a problem that you're comparing military technology (sacrifice everything for toughness) with civilian tech (sacrifice everything for economy). You should clarify if you really want to use the upscaled but otherwise exact copy of a civilian motor in a tank, or it's just general idea of "let's use an electric motor". BTW Maus tank ran on electric motors, albeit with motor-generator pack instead of batteries.

@Thucydides Seriously? The "long tailpipe" theory? You do know that's been debunked for years now, right?

@Agent_L read the last 2 lines

@Thucydides: Not true that 80% of electricity comes from coal (for the US: not sure about worldwide). Roughly 1/3 coal, 1/3 natural gas, 1/3 nuclear, hydro, solar and other near-zero emission tech. (Source eia.gov/tools/faqs/faq.cfm?id=427&t=3 )

in denmark almost all electricity comes from windpower

@jamesqf: He said "thermal", and used coal as an example. That site puts it at 67% vs. 80%. Not a whopping mistake.

@Magic-Mouse: This wikipedia article cites 47% wind/solar/hydro in 2014. There's still 30% coal-based electricity. This article says wind power was up to 42% in 2015. Certainly a lot higher than the U.S.'s 7% from all renewable sources, but not exactly "almost all". That said, they are trying to hit close to 100% renewable sources by 2050 which fits the "sci-fi future" context of your question.

Also, does this mean both sides in the war are using this tech? It's got me thinking about why these dudes, who are inciting destruction through violence, care so much about their carbon footprints...

From the Wikipedia article linked: "Tesla ... later reported it as 463 hp (345 kW) because the two motors do not give their maximum power at the same time." Also, the M1 Abrams produces 2,750 lb-ft of torque at 1500hp. The Tesla S torque curve is pretty sick with ~850 lb-ft of torque, but the curve characteristic is completely different. 2 Tesla S motors would probably just melt trying to accelerating Abrams to 60mph.

Related: forums.tesla.com/forum/forums/current-model-s-motor-limitations

@Comintern From the question: "Assume the R/D department will use the patent to develop their own product rather than retrofit existing Tesla hardware, thus making motors and batteries more "war"-friendly."

@HarryDavid it means a top secret R/D facility is making the next-gen tank. If the "version 0.1" would be feasible to try and produce, and what challenges they would have to overcome.

@MichaelS the reason it is 47% is because you cannot control the flow of the wind, making the country at some points having an over production and at some points having an under production, also the coal produces warm water, and even though it isnt zero-emission they burn dried grass and not fossil fuel, even though it is a "coal power plant"

@Magic-Mouse @Magic-Mouse, okay then.