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Voltage drop with Sony XD Cam


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#1 Colin Donahue

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Posted 29 April 2007 - 06:47 AM

I have been using a Sony XD Cam with my archer on a show for the last month. I was using one dionic 90 on the camera and one on the sled. Since my Dionics all died I now use a hytron 140 at the bottom of the sled to power everyting. The power goes from my stage to the 4 pin on the back of the camera.
I have noticed a significant voltage drop when powering the camera through the 4 pin verses the anton bauer plate on the back of the camera. It is about 1 volt. My hytron 140's fresh off the charger will read only 14.4 volts or so in the camera viewfinder when powered through the sled. If i take the same battery and snap it onto the back of the camera, it will read 15.5 in the view finder. There must be some circuitry that drops the voltage in the 4 pin connector. Has anyone noticed this with other video cameras?
If you are shootng full size video cameras, what is your normal battery setup?

colin donahue
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#2 Jeff Muhlstock SOC

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Posted 29 April 2007 - 07:41 AM

Hey Colin, are you sure the voltage is actually dropping? or is this what the camera warning indicator is saying? The reason I ask, is, many of these eng cameras have a menu setting that must define what your battery chemistry is. I cant recall if XDCam requires this or not, but I have run into this problem with other sony's. The camera will actually shut down and sound an alarm well before the battery is toast. There may even be a setting that you need to tell the camera your using another power source (rather then its Batt plate). Of course you could have something as simple as a bad cable (replace that first). I have used this camera many times with 2 dionics and a 4 pin XLR cable and never experienced this trouble.

Good luck,

Jeff
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#3 Robert Starling SOC

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Posted 29 April 2007 - 09:54 AM

Has anyone noticed this with other video cameras?
If you are shootng full size video cameras, what is your normal battery setup?


Hi Colin:

I had a similar if not identical issue with a Varicam last Sunday. My sled batteries (two IDX 10) were showing 60-80% but I was getting low battery alarms on the camera. Even the camera LED battery indicator was showing low battery but it never shut off. I figured it was some sort of setting but I did not have time to find it buried in the menu. It made the Director very nervous so I just swapped batteries more frequently.

I later spoke with Steve Fracol who explained what was happening and where to make the changes. Normally I bring a manual for every camera I work with but I forgot on this job. Shame on me! Maybe I'll download them to my TREO phone and just keep them with me all the time. It wouldn't be a bad idea to have a library here on the forum where people can upload manuals to the various equipment we use?
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#4 Eric Fletcher S.O.C.

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Posted 29 April 2007 - 12:49 PM

have noticed a significant voltage drop when powering the camera through the 4 pin verses the anton bauer plate on the back of the camera. It is about 1 volt. My hytron 140's fresh off the charger will read only 14.4 volts or so in the camera viewfinder when powered through the sled. If i take the same battery and snap it onto the back of the camera, it will read 15.5 in the view finder. There must be some circuitry that drops the voltage in the 4 pin connector.



It's not circuitry it's just the wiring. What rig do you have? Some rigs have a greater voltage drop than others. I know of two rigs that have 14ga up the post (XCS Ultimate and U2) everything else has smaller wire running up the post. The MK-V stuff is horrifically under gauged throughout the rig using 20 gauge wire as the primary input wire off the battery mounts and then going up a 6 foot coiled cable (over a 14 foot run BEFORE the power cable from the stage) on that rig you can see a 3+ volt drop with large draw cameras.

The greater the amp draw of the camera the greater the voltage drop will be. That's why proper wire sizing is so important. Remember integral super-post's are 12 foot of wire run (You use total current path which is double the cable length) Most rigs are 18 gauge wire, XCS Ultimate and Tiffen U2's are 14ga and the MK-V is 20ga. HD cameras can pull up to 15 amps (as the voltage goes down the amp draw goes up) as can the 435 when starting.

Here is a great online calculator that will illustrate the types of losses being seen. Voltage drop

This also illustrates why low cycle batteries are preferred. Since they are "Stiffer" and have less voltage droop under load.
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#5 RobinThwaites

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Posted 29 April 2007 - 02:53 PM

Hi Colin

You mention Archer and 4 pin, are you using the 4 pin Hirose to power the camera? The Lemo would be better. XD Cams do draw quite a lot of current and NiMH batts have a shallow curve meaning that the camera low battery setting activates early.

Robin
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#6 Rob Vuona SOC

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Posted 29 April 2007 - 06:31 PM

I have been using a Sony XD Cam with my archer on a show for the last month. I was using one dionic 90 on the camera and one on the sled. Since my Dionics all died I now use a hytron 140 at the bottom of the sled to power everyting. The power goes from my stage to the 4 pin on the back of the camera.
I have noticed a significant voltage drop when powering the camera through the 4 pin verses the anton bauer plate on the back of the camera. It is about 1 volt. My hytron 140's fresh off the charger will read only 14.4 volts or so in the camera viewfinder when powered through the sled. If i take the same battery and snap it onto the back of the camera, it will read 15.5 in the view finder. There must be some circuitry that drops the voltage in the 4 pin connector. Has anyone noticed this with other video cameras?
If you are shootng full size video cameras, what is your normal battery setup?

colin donahue

---------------
Hey Collin,
as Mr. Muhlstock said, this happened to me in Hawaii a few months back and it turned out that it was just a simple cable, but it wasn't until we tried all the menu items in the camera setting it to read specific voltage and different battery configurations.

Calll if you like
Say hey to the gang
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#7 Sydney Seeber

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Posted 29 April 2007 - 06:31 PM

I use the different versions of XDCAM quite a bit, and it definitely regulates the voltage coming into the 4 pin connector. I've got 3 power supplies, varying from 12V/13amp through 14.4V/8amp Or something like that) and the XDCAM always reads a constant 13.6 volts, no matter what power supply I use... If I power the camera through the rig, it then will always read at around 14.4, and works its way down from there... It didn't seem to matter what type of battery I used, i.e. Li-ion or the hytrons, even different brand names had no effect... I've never bothered asking why, but tomorrow, I'm going to be around a bunch of Sony engineering types, and I'll ask one of them...
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#8 Colin Donahue

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Posted 29 April 2007 - 10:54 PM

Thank you for all your replies.

Here is a bit more information:
My sled is the Tiffen Archer.
I believe the cable I am using is good.
I am connecting from the lemo on the sled to the 4 pin into the camera
The battery setting in the menu of the camera is for "other battery (not sony) and or external power input", so I beieve I have the right setting on the camera, but I will check with Wexler engineers tomorrow. There is a page in the menu on battery voltage that does not exist in the manual.

Voltage drop from the wiring through the sled?
That was one of my first thoughts. I do not know the gauge of the wire going through my post. I did put a volt meter at the end of the 4 pin xlr cable that is connected to the lemo on my stage and got 15.5 volts .... the same as when I hooked the volt meter directly to the battery.

Then I took a standard anton bauer plate to 4 pin adapter put the same battery on it and plugged the four pin into the camera. I got the same voltage in the viewfinder(14.4) as when it was powered off my sled... and the cable on the anton bauer to 4 pin plate was only 8 inches long. I do not know the gauge of that wire, but it was a pretty fat cable. So am thinking it is not a voltage loss through the sled.

It is possible that the camera is getting the proper voltage but interpreting it lower rate. I never had the battery actually die, because I kept changing them when they got down to 13 or so volts.

I will post more info after I talk to a few engineers

Thanks again,
colin
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#9 Eric Fletcher S.O.C.

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Posted 30 April 2007 - 12:35 AM

Voltage drop from the wiring through the sled?
That was one of my first thoughts. I do not know the gauge of the wire going through my post. I did put a volt meter at the end of the 4 pin xlr cable that is connected to the lemo on my stage and got 15.5 volts .... the same as when I hooked the volt meter directly to the battery.



You have to measure the voltage under load. Running no load you will read the same voltage. It's under load that you see the voltage drop
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#10 Sydney Seeber

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Posted 30 April 2007 - 05:36 PM

As I said, I asked some Sony engineers about this today... I was told that absolutely yes, the voltage is regulated from the 4 pin, and separately at the battery mount. Then, it is variably inverted for the various components within the camera. Oddly enough, this is not the case at the cameras different power taps. From what I understood, the power taps are more of a throughput. The conversation was INCREDIBLY technical, and only after I had them Homer Simpson it down for me several times, did I glean this info...
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#11 Colin Donahue

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Posted 24 May 2007 - 12:02 AM

As I said, I asked some Sony engineers about this today... I was told that absolutely yes, the voltage is regulated from the 4 pin, and separately at the battery mount. Then, it is variably inverted for the various components within the camera. Oddly enough, this is not the case at the cameras different power taps. From what I understood, the power taps are more of a throughput. The conversation was INCREDIBLY technical, and only after I had them Homer Simpson it down for me several times, did I glean this info...



Thanks to all for the helpful information. I got busy and forgot to post. I think it was a case of the XD camera interpreting the voltage at a lower rate. On one of the b-roll shoot days, I just left the battery on when it got below 13 volts and just waited for it to die. It hung in there for another 40 minutes or so.

Colin Donahue
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#12 Stephen Press

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Posted 24 May 2007 - 05:51 AM

If you are having any XD issues I recommend posting on the www.xdcam.com.au forum. Clive an engineer from over here in New Zealand is a fantastic resource for fixing all problems XD.
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