Its the retail price of the aluminium-air battery to be sold to the general public that's the problem, its too expensive.
If we take the average family annual mileage of around 6,000 miles, one would need to replace a Trevor Jackson battery 4 times in just 12 months, that would cost you £20,000 per year. Obviously there is no charging cost involved, but you would need to account for the price of each battery replacement after every 1,500 miles, plus the battery replacement labour charge, this would give you an average running cost of £3.33 per mile + the additional labour charge... I'm just throwing figures around, nothing written in stone.
If we compare those figures to a regular EV being used on the roads today at an average running cost of just 5p per mile, you can see how ridiculously expensive an aluminium-air battery vehicle would cost to run, even a petrol car averages at 12p per mile.
They recommend a Nissan Leaf battery to last 8 years or 100,000 miles, and Nissan have now brought down their price for a new battery to just under £5,000. When you compare that figure with having to purchase 4x aluminium-air batteries per year for 8 years, this would cost you a whopping £160.000 (32x batteries).
I agree with the video above, the aluminium-air battery would be a fantastic idea as a range extender, used in EV's to give an increased mile range when needed. Its pretty much safe to say these aluminium-air batteries are a lot cheaper to make than lithium-ion batteries, so they really need to carry the cheaper price tag to be able to succeed.