On a general battery point, lead acid batteries do not "like" to be fully discharged, their prefered life is being topped up regularly. NiCad batteries on the other hand like being "cycled" through fully charged to fully dischrged, in fact as any model owner will tell you, you can "rejuvinate" NiCads by charging them fully and discharging fully a number of times and each cycle will increase the power held in the battery.
Lithium Ion (not Iron
) are much less fussy as are NiMH, but they are pricey. easily 4 times the pice of NiCad