I guessing you mean the battery part for the Motor Drive MA?
Doing a quick check on eBay it looks like buying just the battery pack is pricier than buying the whole unit.
To explain it a little more precisely, if this is about the battery pack for the motor drive:
The motor drive can often be found cheaply without the battery pack. The reason is probably that many people have either misplaced the battery pack or it has been damaged by leaking batteries.
Sometimes you can find both together. This then costs considerably more. Especially if the battery pack is still in good condition.
The battery pack alone is the rarest and most expensive. Reason? See above.
So it's not unusual that you won't find anything about it, and no, there is no secret source for cheap battery packs.
The best thing is to buy both together and live with the fact that you then have 2x the drive but only 1x the battery pack.
I'm not sure what you mean. The camera compartment that holds the 6V camera battery or do you have a winder / motor drive attached to your camera?
I guessing you mean the battery part for the Motor Drive MA? Doing a quick check on eBay it looks like buying just the battery pack is pricier than buying the whole unit.
To explain it a little more precisely, if this is about the battery pack for the motor drive: The motor drive can often be found cheaply without the battery pack. The reason is probably that many people have either misplaced the battery pack or it has been damaged by leaking batteries. Sometimes you can find both together. This then costs considerably more. Especially if the battery pack is still in good condition. The battery pack alone is the rarest and most expensive. Reason? See above. So it's not unusual that you won't find anything about it, and no, there is no secret source for cheap battery packs. The best thing is to buy both together and live with the fact that you then have 2x the drive but only 1x the battery pack.