DRAFT: TO BE REVISED AND UPDATED SHORTLY!! (RN)
Lead acid batteries should not be discharged and kept charged up as much as possible. Discharging these batteries will reduce their capacity. if they are kept for any length of time without a charge, they will not charge up again.
To charge up these batteries use the same formula.
However lead acid batteries can cope with heavy currents and it is sometimes a good idea to charge them up with a higher current. Now and then charge them up with double the current as usual and for half the time.
So for example, a 5000mA/h battery, should be charged on 1 Amp for 5 hours.
To ensure they will be fine when next used make sure they have a top-up charge every couple of weeks. Half the length of time of a normal charge.
DO NOT HAVE THE BATTERY ON A CONSTANT TRICKLE CHARGE!