Electric vehicles have been generating a lot of interest in the media as fleet operators begin trialling 7.5 tonne electric trucks for use in inner-city areas. Now Smith Electric Vehicles is developing bigger trucks, capable of carrying much more. Although Kevin Harkin, sales director is adamant that the company will not be entering the hybrid market, he is confident that increasing progress in battery and truck technology is making electric trucks a viable option and reckons that Smith Electric has “trebled the boundaries of range” in the past three years.
He says that in the past a lead acid battery would only allow a 7.5 tonner to carry about 1.5 tonnes of product [50 miles] while now a truck doing the same work can carry 3 tonnes. “It’s a huge leap,” he says, but admits that the batteries are still heavy compared to a tank full of diesel.
Smith is now working on a 12 tonner targeted at European and US markets and is even investigating an 18 tonne version, but currently the battery technology is dictating the development of electric trucks. “There’s only so much space on a vehicle to put batteries.”
Currently Smith is using Sodium Nickel Chloride batteries, but Harkin says there are new batteries being developed that will allow a quicker recharge.
Unlike Nickel Cadmium batteries, Sodium Nickel Chloride batteries prefer “opportune charging” rather than being fully discharged and then completely recharged, these can use for instance, 30 per cent and then be recharged for 30 per cent. The technology currently has a gauge with a digital display that is accurate to point one of a per cent. The latest battery technology is Lithium ion which Harkin reckons could unlock even more doors to the use of electric trucks. It has a greater energy density and a greater number of Kilowatt hours per kilogram of weight than Sodium Nickel Chloride.
