External Battery solution for GH4, A7s, ...

[bobodude]

Hi,

 

I am looking for an External Battery solution for GH4, A7s, ...

I have looked around but would like to know if anyone has any personal experience, and which gear you chose,

Right now I am thinking of a V-mount setup, or Paglink,

but haven't found heaps of info of people using these setups with smaller cameras ...

any info apreciated

 

[studiodc]

Depends on what you want to do. I picked up a couple very nicely made power converters from a forum (8.8 V is confirmed to trigger the AC input mode of the GH4 - how far above that you are comfortable going is up to you - the specs aren't published) and a cheap battery drop-in with a DC plug on the end (the drop-in is dumb and doesn't convert to the proper voltage so you have to give it the right voltage ahead of time). You can get that on eBay and I can't see why you'd pay for the Panny one when all it is is a connection between the +/- on the battery plates and a DC barrel jack.

After that, feed it with any battery source you want from 3-30V (or whatever your converter box will accept). I use both the Varavon batteries (the 7.4V and 12V units, don't need the GH4 specific one if your converter is external) for lightweight kits and run it from my V-mount for gimbal and shoulder rig operation (the v-mount battery is part of the counterweight for the shoulder rig). 

But I'll be honest, the GH4 lasts SO LONG on the internal battery it's ridiculous. Several hours. So I always keep one or two of those as a spare and know I'll have at minimum 3-5 hours of shooting reserve time. So the only real motivation to go to an external battery for the GH4 is if you're powering the rest of your rig off the same source (e.g. EVF, recorder, possibly a wireless FF, gimbal, or other active stabilization, lights, etc), and you want to only manage one battery type. Then I can see it being quite useful.

I would expect the same exact idea applies to the A7s and any other camera, get the dummy battery for AC operation, set your variable DC-DC converter to the appropriate voltage, then plug it into any battery raw output you want (no further conversion is necessary - you can run it off a raw D-Tap output, a 9V cheapo store battery or a 4AA holder, car battery, drone internal 3s or 4s Li-Po, whatever). At that point you can also look at the seriously low-cost model lithium batteries too - some of the lowest cost per watt out there and there are some very reputable brands to choose from now. 

A good dc-dc converter should accept anywhere from 3-30V DC and be able to customize the output to the exact voltage you want (usually using a little screw inside the box, you turn it to where you want and then set it with a dab of hot glue so you can change it in the future if you need to). I got mine from a chap on another forum who makes really quality gear, but again, you can get them with a little searching nearly anywhere for between 10-20 EUR depending on features, size, etc.