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The easy way is to buy a 12V battery (Lead Acid, NiMH, Li-Ion, LiFePO4), connect it to an inverter (min. of 100W), then just plug in the original AC adapter. The AC adapter should be switched mode power adapter so the inverter can be modified sine wave.
Advanced DIY is to buy a 4-pin XLR female connector (same pin-out as the light), and connect it to any 12V DC power source you have. It seems the light max. power draw is 82W, I'd say buy a battery with min. 10Ah capacity. You have to figure out the pins (positive and negative) yourself though.