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If I plug BMCC into 14.8v output will it draw 14.8v or 12v?

PostPosted: Wed Dec 06, 2017 6:31 pm
by ScottHendrix
I have a BMCC with a VMount Maxoak battery with Fotga power supply/vmount splitter. The Maxoak battery says 14.8V 177Wh, 12000mAh. The Fotga vmount supply the battery is on has a 12v DC output and a 14.8v Vemo output. I know the BMCC can accept a 14.8v but what I'm wondering is: If I connect the 12v output to the camera I know it is using 12v from the battery, but if I connect the 14.8v Vemo out from the Fotga supply to the BMCC is it going to be consuming 12v or 14.8v? I just want to know if using the Vemo 14.8v output is going to end up using more of the battery unnecessarily.

I need to use the 12V DC output to power my monitor so that is the reason I am asking about this. I searched Google and on the forum here but didn't find quite this same question.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Wed Dec 06, 2017 7:59 pm
by Pavel Lavrov
The camera will consume as much power as it needs. So at the end camera does not consume voltage but current. The power is measured by multiplying voltage by current.
But all you have to worry about is supported input voltage. The rest will depend how big your battery is.


Sent from my iPhone using Tapatalk Pro

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Wed Dec 06, 2017 9:54 pm
by ScottHendrix
Pavel Lavrov wrote:The camera will consume as much power as it needs. So at the end camera does not consume voltage but current. The power is measured by multiplying voltage by current.
But all you have to worry about is supported input voltage. The rest will depend how big your battery is.


Sent from my iPhone using Tapatalk Pro


Thanks for the reply. So you're saying that the draw on the battery is entirely dependent on the consumption of the camera it is powering? So the battery will last just as long using the 14.8v output as it would if I used the 12v output to the camera?

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Wed Dec 06, 2017 10:25 pm
by rick.lang
Likely no difference in the life of the battery providing sufficient voltage to operate the camera.


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Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 12:10 pm
by Gene Kochanowsky
The power draw from the battery does depend on how the camera regulates voltage internally. If it uses linear regulators then powering the camera with a higher voltage will be more inefficient than powering with a lower voltage. If the camera regulates voltage internally with a switching regulator there may be a negligible difference at best. I have no idea how that particular camera regulates voltage internally. You might be able to tell by running the camera from one then the other source for 10 minutes and seeing if the camera is warmer using the one source vs the other. Allow the camera to cool down between tests. Linear regulators will dump more power as heat with the larger voltage.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 4:14 pm
by Kim Janson
Normally there is no 12V or 14.8V batteries unless they are spesially regulated.

Normal V-Lock battery is 12V - 16.8V. 16.8V when fully charged, 12V when empty.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 5:43 pm
by Denny Smith
what I'm wondering is: If I connect the 12v output to the camera I know it is using 12v from the battery, but if I connect the 14.8v Vemo out from the Fotga supply to the BMCC is it going to be consuming 12v or 14.8v?


The camera power connection can use either one, 12-VDC is the minimal connection, around 17VDC the max connection. The camera does Not draw voltage, only current (measured in watts). If you connect the 14.5 VDC tap, the camwera’s power supply will draw 14.5VDC and convert it to the various voltages needed by the camera. Normally the 14.4-16.5 VDC Power tap is better.
Cheers

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 6:50 pm
by Lee Gauthier
Somebody asked me this, and I found I had no good answer:

V-lock batteries are very expensive. Isn't there a way to use 18v power tool batteries like Makita to power the BMDCC or pocket?

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 7:13 pm
by Gene Kochanowsky
Have you considered something like this?

https://www.amazon.com/HitLights-Rechar ... le+battery

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 7:17 pm
by Kim Janson
Sure there is, just add inverter that lowers the voltage to suitable level, but is that really what you want to do.

And you could use also RC LiPo batteries that come with some fire hazard, but are inexpensive....

IMO the V-lock batteries are well worht the money.

Lee Gauthier wrote:Somebody asked me this, and I found I had no good answer:

V-lock batteries are very expensive. Isn't there a way to use 18v power tool batteries like Makita to power the BMDCC or pocket?

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Thu Dec 07, 2017 11:31 pm
by Robert Niessner
Lee Gauthier wrote:Somebody asked me this, and I found I had no good answer:

V-lock batteries are very expensive. Isn't there a way to use 18v power tool batteries like Makita to power the BMDCC or pocket?


Yes, a guy in the German forum Slashcam.de has done exactly this:
https://www.slashcam.de/forum/viewtopic ... 6&t=138379

You can use Google translate to read it.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Fri Dec 08, 2017 1:16 am
by Denis Kazlowski
Robert Niessner wrote:
Lee Gauthier wrote:Somebody asked me this, and I found I had no good answer:

V-lock batteries are very expensive. Isn't there a way to use 18v power tool batteries like Makita to power the BMDCC or pocket?


Yes, a guy in the German forum Slashcam.de has done exactly this:
https://www.slashcam.de/forum/viewtopic ... 6&t=138379

You can use Google translate to read it.


OMG! There is a Makita battery hanging off the back of the URSA Mini. This is fantastic! :-)

Cheap V-Mount batteries could be had for the same price as good power tools batteries though. $70 USD vs. 2x $140 USD.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Fri Dec 08, 2017 1:24 am
by Denis Kazlowski
Denny Smith wrote:
what I'm wondering is: If I connect the 12v output to the camera I know it is using 12v from the battery, but if I connect the 14.8v Vemo out from the Fotga supply to the BMCC is it going to be consuming 12v or 14.8v?


The camera power connection can use either one, 12-VDC is the minimal connection, around 17VDC the max connection. The camera does Not draw voltage, only current (measured in watts). If you connect the 14.5 VDC tap, the camwera’s power supply will draw 14.5VDC and convert it to the various voltages needed by the camera. Normally the 14.4-16.5 VDC Power tap is better.
Cheers


I think you mean Amps - not watts.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Fri Dec 08, 2017 1:33 am
by Denis Kazlowski
ScottHendrix wrote:I have a BMCC with a VMount Maxoak battery with Fotga power supply/vmount splitter. The Maxoak battery says 14.8V 177Wh, 12000mAh. The Fotga vmount supply the battery is on has a 12v DC output and a 14.8v Vemo output. I know the BMCC can accept a 14.8v but what I'm wondering is: If I connect the 12v output to the camera I know it is using 12v from the battery, but if I connect the 14.8v Vemo out from the Fotga supply to the BMCC is it going to be consuming 12v or 14.8v? I just want to know if using the Vemo 14.8v output is going to end up using more of the battery unnecessarily.

I need to use the 12V DC output to power my monitor so that is the reason I am asking about this. I searched Google and on the forum here but didn't find quite this same question.


Hi, Since I did not try this on a BMCC I am unsure if the voltage regulator in the BMCC can sustain over-current/over-voltage situations well. Most broadcast and film gear is okay playing in the voltage ranges of Lithium ION batteries from 11+ volts to 19+ volts while the optimal voltage is 12+ DC. In terms of battery consumption the camera will take what it needs at whatever voltage. As Lithium ION discharges it drops in voltage slowly, measuring this voltage is kind-of how the all Li powered equipment can produce progress bars of battery left. Depending on charge controller quality of your V-Mount battery and age of cells, you can have it output up-to 24v by accident if overcharged. As the Fotga outputs 12v it down-coverts current prob. between 9.5v - 13.5v - I think it would be safer to use 12v out for you to match the 120 AC/DC power supply for BMCC then gamble on internal circuits of the BMCC to protect from high voltage Li-Ion output.

Do ask Fotga if the current on 14.8(14.4) is Direct or regulated in the adapter. I know they have a more advanced model of this under the brand JTZ which has it's own internal charge controller and LiOn cells. That one may be safer.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Fri Dec 08, 2017 1:37 am
by Denis Kazlowski
Lee Gauthier wrote:Somebody asked me this, and I found I had no good answer:

V-lock batteries are very expensive. Isn't there a way to use 18v power tool batteries like Makita to power the BMDCC or pocket?


Just purchased 3x V-MOUNT 130 AH for $67.00 each. Also I am no 100% to exclude this but power-tool batteries are different chemistry NiCD or NiMH, I've not seen too many Lithium Ion, but then again I don't buy new tools often. They have a different discharge curve than Li that may mess with the DC out the cameras expect.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Fri Dec 08, 2017 9:38 am
by Howard Roll
Draw is a function of the watts required, it has nothing to do directly with amps or voltage. If your camera requires/draws 20 watts it would draw 1 amp @ 20 volts or 2 amps at 10 volts. A watt is fixed as is voltage, amperage is relative. Ohms law, dig it.

Re: If I plug BMCC into 14.8v output will it draw 14.8v or 1

PostPosted: Fri Dec 08, 2017 2:01 pm
by Kim Janson
Usually mostly so, but not exactly and not always ;)

The not exactly: Inverters that cameras use are not 100% efficient, usually they are between 80 to 90% and this efficiency depends of input voltage and output current.

The not always: If it is linear regulator and the camera consumes 2A, that will also show on input side, i.e at 20V the camera would still consume 2A, total 40 W and the regulator would get pretty hot with the 20W it needs to waste

Sorry, it just has been long Friday... Usually and in general it is just as you say.

Howard Roll wrote:Draw is a function of the watts required, it has nothing to do directly with amps or voltage. If your camera requires/draws 20 watts it would draw 1 amp @ 20 volts or 2 amps at 10 volts. A watt is fixed as is voltage, amperage is relative. Ohms law, dig it.