Here’s how to maintain continuous external USB battery power with Sony a7 III, a7R III, a7R IV, a7S III, a9, a9 II & a1 cameras while tethering through the USB-C Port:
(1) Tether Tools Relay Coupler NPFZ100 ($35 from B&H Photo)
(1) Tether Tools Case Relay* ($100 from Amazon | B&H Photo)
(1) USB Power Bank of your choice (Available from Amazon)
*Case Relay has a built-in 7.4V, 1,200mAh lithium battery which adds the ability to hot swap USB Power Banks without shutting down.
Sony’s new NP-FZ100 batteries pack a lot of power yet if you find yourself needing more, Sony NPA-MQZ1K Multi Battery Adapter Kit might be just what you need for time lapse photography or extended video shoots since it is able to supply power from up to four NP-FZ100 series battery packs for dramatically extended shooting times. At four bills – it’s not cheap, but it includes two NP-FZ100 batteries that would run you $160.
Sony NPA-MQZ1K Multi Battery Adapter Kit can also serve as a rapid charge, with a charging rate of 480 minutes for four batteries. Users can convert the adapter into a more compact two-battery adapter for a more travel-ready kit.