Pocket 4K - Estimated runtime with V-mount Battery

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nsnjr1

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Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 23, 2019 10:28 pm

I'm trying to build a rig which is all powered by a V-Mount battery and I am trying to estimate the runtime for the battery. I am looking at the D&O Lighting brand 95wh battery and will be using a D-Tap splitter to power my camera via 12v, a monitor, and maybe a recorder. I was told by Blackmagic that the camera draws 22 watts which seems a little high and would only give me about 4.3 hours of runtime on that battery with only the camera connected. 4.3 hours seems too low and I just want to verify that my math is correct and see if others are getting longer runtimes with v-mount.

Thanks!
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Ryan Humphrey

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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 23, 2019 10:44 pm

That's about right. According to a conversion calculator I just googled a standard lp-e6 battery (7.2V 1800 mAh) is about 14 Wh equivalent. A Pocket 4K gets about 45 minutes from one of those batteries. 95 Wh is 6.75x more juice which works out to 5 hours of run time.

Now, it's not that exact in real life and my math is all approximate and it will vary based on actual batteries and things. But 4.5 hours, give or take half an hour, is the right ballpark.
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Robert Niessner

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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 23, 2019 10:45 pm

The math is correct. But you have to account the power draw of an SSD (3-4 W) or CFast card (~1.5 W).
Screen brightness has some effect and the environment temperature. Out in the cold the camera might draw less because the Peltier doesn't have to cool so much.

I was shooting a few days ago with the PCC4K (CFast, screen 100% brightness) out in the cold (~0°C) for 2 hours. Power supplied by a 128Wh Swit V-mount battery (bought 2013). After 2 hours the battery showed still 3 out of 4 leds.
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Pete Tomkies

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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostThu Jan 24, 2019 12:37 am

nsnjr1 wrote:I'm trying to build a rig which is all powered by a V-Mount battery and I am trying to estimate the runtime for the battery. I am looking at the D&O Lighting brand 95wh battery and will be using a D-Tap splitter to power my camera via 12v, a monitor, and maybe a recorder. I was told by Blackmagic that the camera draws 22 watts which seems a little high and would only give me about 4.3 hours of runtime on that battery with only the camera connected. 4.3 hours seems too low and I just want to verify that my math is correct and see if others are getting longer runtimes with v-mount.

Thanks!

"Seems too low" why?

If you want to power all the extra kit then you will need a bigger battery or have to accept shorter runs times.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostThu Jan 24, 2019 1:29 am

I can confirm that using a 87wh Vmount (plugged into the 12v input out of the DTAP) I get around 5 hours runtime with Camera only recording to an internal C-Fast (no ssd, no phantom power).
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostThu Jan 24, 2019 4:14 pm

108Wh battery will give you 6h 40min of continuous recording of UHD ProResLT in to SSD T5.

It depends of battery controller. Mine will cut power whet battery will be at 10.5v
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostThu Jan 24, 2019 5:58 pm

Pete Tomkies wrote:
nsnjr1 wrote:I'm trying to build a rig which is all powered by a V-Mount battery and I am trying to estimate the runtime for the battery. I am looking at the D&O Lighting brand 95wh battery and will be using a D-Tap splitter to power my camera via 12v, a monitor, and maybe a recorder. I was told by Blackmagic that the camera draws 22 watts which seems a little high and would only give me about 4.3 hours of runtime on that battery with only the camera connected. 4.3 hours seems too low and I just want to verify that my math is correct and see if others are getting longer runtimes with v-mount.

Thanks!

"Seems too low" why?

If you want to power all the extra kit then you will need a bigger battery or have to accept shorter runs times.


4.3 hours seems low since other people are saying they can get 5-6 and a 22 watt power draw seems high for this camera.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostFri Jan 25, 2019 4:56 am

With my Core SWX 98wh battery, I get about 3.5 hours of use powering the BMPCC4K, SSD, and the Atomos Inferno monitor (not recording on it though). I record soccer games, 2 x 40mins, give or take a few minutes. I can usually get 2 games on a single 98wh charge.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostSat Jan 26, 2019 1:48 pm

I'm powering camera, 7" high bright monitor and follow focus motor with a 190w battery. I let it run recording RAW to a T5. Over the course of six hours I filled and erased the card several times. The battery meter showed half full.

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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 10:23 am

Sorry for hi-jacking with a slightly off-topic Q:

Can anyone point me towards a reasonably priced d-tap-splitter? I'd just like to power the P4K and a field monitor with a v-mount-battery, but either I find 4x-d-tap-splitters or this one and only expensive 2xsplitter:

Hawk Woods PC-8
https://www.nefal.tv/de/hawk-woods-pc-8 ... gKorfD_BwE

Thank you!
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 1:52 pm

Thomas Schumacher wrote:Sorry for hi-jacking with a slightly off-topic Q:

Can anyone point me towards a reasonably priced d-tap-splitter? I'd just like to power the P4K and a field monitor with a v-mount-battery, but either I find 4x-d-tap-splitters or this one and only expensive 2xsplitter:

Hawk Woods PC-8
https://www.nefal.tv/de/hawk-woods-pc-8 ... gKorfD_BwE

Thank you!

Often your battery will have a tap and your plate will have a tap. That's how I do it, at least.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 4:29 pm

Joe, I would think that’s a much safer solution. If using a splitter, that port is perhaps going to need to output more amperes than it might be designed to handle—especially a 4x splitter that might fry some wires or other internal circuitry. I know my Cinegears 250 Wh (16+ amps) can easily handle a situation in which the battery D-tap and the battery plate D-tap are both being used while the same battery powers the camera.


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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 7:28 pm

Thanks Joe and Rick, much appreciated!

Guess I'll just run the monitor on my bucketload of then spare LP-E6 then as I went cheap with the plate, which is only a v-lock-mount w/o a d-tap.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 8:06 pm

Thanks Ray,

already began looking at these, but I wonder whatever will need power on my small rig except the field monitor. Audio recorders seem to run forever on their own batteries..
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 8:31 pm

Valid arguments - still I have plenty of LP-E6 lying around, so I guess I#ll have to wait and see before I buy one of those helpful plates. Just bought a (still cheap) v-mount-battery, a (used) Fuji XT3 ... :oops:
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 8:32 pm

https://www.amazon.com/ideas/amzn1.acco ... 0TTAGVFD29

This is the one I'm using. $100. I'm powering the camera, 7" monitor and Nucleus Nano motor. DId an 8 hour shoot on Sunday and only used half the battery. SO nice to not even have to think about checking battery meter.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 8:37 pm

Australian Image wrote:The downside is that it does make the rig a lot heavier and you need to balance the weights, but you can't get something for nothing.


Heavier, yes. But if well rigged, potentially better balanced and actually more comfortable to operate than a lighter set-up. (I can support my front handles with one finger.)

Plus, a light handheld rig is nearly impossible to operate smoothly, while a well balanced shoulder rig yields watchable "handheld" footage.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 8:47 pm

Thanks Joe, saw your link in another thread (over at bmcuser?) and that got me initially changing my mind and letting go of my Anker Astro solution.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostWed Jan 30, 2019 10:33 pm

Australian Image wrote:That said, I've also made it so that it's quite stable when I hand hold it at waist level (which I prefer to eye level), by using the shoulder pad as a brace for the waist. And yes, I've also been of the view that overly lightweight cameras are worse for stability than heavier cameras, having some mass always makes for a far stabler unit.


That's an interesting set-up.

I agree that shoulder mount isn't the end-all-be-all. I actually do need to make a tweak to my rig to make it easier to take on and off a tripod, and it is too long to reasonably fit in any case. (I'm gonna split it into two lengths of rods so that it can essentially break in half for transport and for very tight shots.)

I have found, though, the there is a tendency for people to become over-zealous in a quest for the most compact rig, to the point that they significantly sacrifice usability. I know I've been guilty in the past, and have made a lot of bad rigs. "Run n Gun" has come to mean holding a DSLR in your outstretched arms, and not only will that kill your arms, your footage will likely be the bad version of shaky-cam.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostTue Feb 05, 2019 8:03 pm

Love this discussion.. know its about vmount initially, but it went the way of how to kit out the rig so you can easily carry/stabilize it.

First, as per a few other threads on batteries, I am really really like the use of 18650s and a simple battery holder, serial soldered, and a simple barrel plug connector setup (or something similar). As I said in another thread, though it was a bit janky because I didnt have it attached to my cage, I powered my BMPCC4K for a bit more than 2 hours with $25 worth of 18650 batteries. The weight was 1/3 or so of my vmount battery too. Now, to be fair, once I add the monitor that needs power, and audio record that needs power, it may go back up in weight, and a vmount would make more sense then. BUT, for quick hand held stuff, this simple little 18650 pack worked well.

I have been looking at the vests + arm route, where you mount a steadicam to the arm, and the arm counter balances the rig. Anyone use those, if so, any good or not worth it... and compared to say the shoulder mount or hip mount?

I am also wondering about these units that you wear with the pole over the head, and you attach the camera to the string that hangs down. Are those any good? They seem a little weird to be walking around with, though I suspect they are easier to work with than the vest/arm setup. They seem to run $1K or more too.. which makes me wonder.. its a bent pole, a spring/string, and tension knob.. might not be hard to make your own. Though I dont know how well they handle walking around with.

The one that really caught my eye is the LAB3 gimbal with the full kit.. it has a belt that you can then attach the gimbal to a clip on it so it helps ease the weight of the gimbal with rig. What I think works here is you can use the gimbal for low to high shots, etc.. but when doing longer walks/jogs/runs with it, attach it to the hip to ease the weight off. Seems like it offers an overall solution.
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Re: Pocket 4K - Estimated runtime with V-mount Battery

PostTue Feb 05, 2019 9:14 pm

Not that this is the right one..but for $700 USD.. it looks decent
https://www.adorama.com/us%20%20%201061 ... 7eEALw_wcB
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