Depends on the opportunity cost. If you need to take time or effort away from your labor to lug a battery along, or your labor is so important or specialized that you would need an assistant just for lugging the battery, the ambulatory battery might be cheaper than trying to do it purely on manpower.
Depends on the opportunity cost. If you need to take time or effort away from your labor to lug a battery along, or your labor is so important or specialized that you would need an assistant just for lugging the battery, the ambulatory battery might be cheaper than trying to do it purely on manpower.
I also imagine they double as a converter. Different voltages, pulses, impedances etc
Plus they gonk.