a7s external power?

Do we have a consence/result here? I would need a connection to a SWIT battery (used by the Odyssey), to have reliable power for hours. My shots take often several hours and its not easy, to always keep power in the eyes. And changing the batteries is not easy, because its blocked slightly by the video head and any movement would destroy the recording.

The reviews at B&H for the SWIT D-Tap cable are a pure catastrophy. It looks as if the cable is really dangerous, at least concerning reliability while using. The first comments in this thread do not mention problems.
How's your long time opinion and experience about that cable? In theory this would be the best solution, but it seems to be an no go.
http://www.bhphotovideo.com/c/search?N=11077513&InitialSearch=yes&sts=pi

Next is the cable by IndiPRO, same price, little box in the middle, one review. Will it regulate to proper Volts, as it says it would be regulated?
http://www.bhphotovideo.com/c/search?N=11124620&InitialSearch=yes&sts=pi
Any image noise created by that cable, as reviewed for the SWIT?

Last is the cable from Wooden Camera, more expensive, big box in the middle - and absolutely no review. Does anybody use that cable with pure success?
http://www.bhphotovideo.com/c/search?N=11105841&InitialSearch=yes&sts=pi

Are there any other solutions out there? I would like to avoid a battery handle for two batteries.
Thanks for any hint!
 
M. Gilden said:
Interesting options!
Olof, I'd like to hear more about your solution. But it sounds like you are feeding it appropriately voltaged battery packs, which means the standard dummy battery floating around amazon and ebay would work find.

What I'm used to being able to do, is buy those standard 9v battery backup boxes and wire it directly up to my GH cameras, like this:

View attachment 94930

I already own a few similar battery packs from doing multi-cam shoots to cover concerts, etc. I know the A7S won't record unlimited length without an external recorder, so I'm working on that as well, but I'd rather not also worry about swapping out batteries from the grip or keeping track of how much juice is left, especially if I had assistants monitoring those cameras. These battery packs can last anywhere from 5-8+ hours of continuous recording on my Panasonic cameras, and it doesn't seem like the A7 series draws more power. I just don't know if attaching 9v would fry the darned things.
Click to expand...

I picked up one of these:
https://www.fasttech.com/products/1424/10004461/1341407

You can put whatever 18650 batteries in it you want, 4x3400mah (50wh) batteries should last about 6-7x as long as one 7.3wh sony battery. You can get top of the line 3400mah cells or cheapo cells and you know exactly what cells are in there as opposed to normal power banks or batteries which are a luck of the draw since many manufacturers advertise very overly optimistic capacity specs, and this one gives you a 0-100 percentage readout of remaining capacity. It has a voltage selector from 5v-13v so you can set it for 7.5v, 8v or 8.5v and in my quick test it worked fine on the A7s with a standard dummy battery. This thing is pretty inexpensive and very handy as a do-it-all power bank if you happen to need to power a 12v, 11.1v, 7.2v, 5v, etc device in the field or even just as a fast USB charger for your phone.
 
Just FYI SWIT and Switronix (NY) are 2 unrelated companies. You are referring to Switronix. From engineering point of view it is hard and expensive to incorporate a voltage converter into a very small space, and make it reliable. That is why others (and our kit) use a small external box for it.

A7-DC-SL-D-Tap-Kit-400.jpg
 
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