@Pint
"also..ok i was to travel from London to inverness for a meeting distance is 456 Miles, Ah Bugger got to add 30 mins into my schduel if i travel by car to charge the dam battery, worse if i want to go further."
456 miles at 70mph would take you about 6 1/2 hours (assuming you could keep that speed up, didn't stop for traffic lights, roundabouts, traffic jams, inevitable roadworks etc). Google maps (London - Inverness) tells me its more like 560 miles and getting on for 10 hours anyway.
So... You plan to leave at, say, 8am, arrive 6pm (ish), and don't intend to eat or drink *anything*; or go to the bathroom ("John" for our American friends) whilst concentrating on driving for 10 hours solid. Okaaay.