They were tried extensively by Scottish Ambulance three or four years ago but, like most things, alternatives have since been found. These batteries are fine, however. Deep-cycle and Leisure batteries are the commonest, in terms of trying to deal with insufficient capacity. Higher levels of discharge are sought in order to increase the amount of available capacity . Virtually all batteries suffer some kind of damage if they do go below this figure, deep-cycle included.
Gel batteries are popular, especially in the marine sector.
These are also very good but expensive and don't handle abuse too well. Again one of the arguments is, if a yacht is upside down in the Atlantic, the last thing anybody would be thinking about is a few drops of sulphuric acid in the equation. Free lead acid battery types don't usually expel acid all over the place, unless they split, of course. As usual, everything comes down to choice and what you want to pay. We take the view that heavy-duty truck batteries combine the best compromises in terms of capacity, performance and price.