Li-Ion technology, despite it's cost, is best suited for electric motors which require a large current draw for climbing slopes. A 36v/10ah Li-Ion battery weighs about 3 kgs and can provide 3 times its capacity (i.e 30 A) in a continuous flow without any risk. Another advantage is that the voltage doesn't sag with a strong current draw like lead acid does. The self discharge rate is low while unused, there is no memory effect and has a good range for it's weight to energy ratio. Depth of discharge follows a flat curve where lead has a rapid drop. 3 Kg of Li-ion can provide up to 60 km of autonomy on flat ground where it would take 15Kg of lead to achieve the same. Li-Ion technology has been proven with years of use in laptops with 99% of electric efficiency and offers better recycling in comparison with lead batteries.