Must battery packs are made up of a number of 12 volt battery packs. All ya have to do is open the battery case, take out the 2, 3 or 4 12 volt batteries that are inside and replace them with something SUITABLE. Please note, you must replace them with something suitable. Not all types of batteries can be used in any battery pack. If you want to change the type of battery chemistry you MAY have to change the electronics in the battery or even the charger.
The number of charges you can get from a battery depends on the chemistry. SLA's usually only last 200-300 charges. I have seen Li-ion advertising 2000-3000 charges. Another issue is that as the battery ages it will give you less and less power, especially the SLA type.
Last edited by pengyou; 10-08-07 at 10:35 AM.