Large amp draw on Epic-W causing low voltage/shutdown

[Kevin Marshall]

I'm working with an Epic-W powered by a cabled v-mount plate into the Base I/O. Normally the camera draws ~4A according to the Power Info page. Occasionally, with an AC7 connected through the d-tap on the plate, the camera starts drawing 6+ amps, and voltage reads ~10.5V, sometimes resulting in an unexpected shutdown. This same battery plate, d-tap cable, and monitor work fine on an Epic Dragon. Anybody seen something like this?

 

[Björn Benckert]

Possibly so that W is more power hungry. I know other cases when people run into trouble when they start feeding power from the camera battery to a lot of other things when shooting helium. Like they did camera tests before shoot and then they go out to film and the AC put on his range finder, extra monitor and motors etc. and all of a sudden the camera starts to behave all strange, no menus, strange shutdowns, no playback etc. So they send back the body to the rental house and they check it without issues and when it comes back... same problem. So yes important to have batteries that can take fast withdrawals and not have to much stuff on the same battery source.

 

[Kevin Marshall]

So as an update on this - the issue is persisting even with no accessories attached. I'm using Red Bricks on the plate, so I'd be very surprised if they couldn't handle the power draw of just the camera body. It's also worth noting that this body just came back from being serviced at RED.

 

[Joel Arvidsson]

How much run time do you get from a redbrick? My Epic w with just a 5" red monitor draws more than the Epic x while in think the manual states it should draw less. Also one redbrick shows up in percent on camera while others shows voltage?

 

[Kevin Marshall]

Sometimes I'll get time remaining, sometimes I'll just get voltage, it depends (even on the same brick). The time the brick lasts varies - sometimes they've lasted the whole 1hr+ without issue, other times it'll only be up for 5-20min before the amperage shoots up and I get the voltage issue or unexpected shutdown.

 

[Kevin Marshall]

It's also always a large jump. Time remaining will read :50, then will either shut down or immediately switch to reading 0:00 or 10.4V. The bricks still show three or more bars. The batteries and plate worked fine on the Dragon body through yesterday, and the batteries with a WC cableless battery plate on this Epic-W through a week of prep until the camera went down and went in for service.

 

[Björn Benckert]

is it the same on all your batteries?
have you tested with another battery plate?

I get this kind of behavior when running off a battery sitting on my back on the armor man and a long cable going down to the gimbal. Simply power fall over the distance of poor cabling.

 

[Kevin Marshall]

All the batteries. Haven't tried another plate yet, but it's on the list. The cable from the plate is only like 6 inches long, so that shouldn't be an issue. I'm currently trying to see if sleep mode is affecting it, as not sleeping the camera seems to make it run longer. I'll have to see how it pans out.

 

[pat fenelon]

Any updates or fix to this? Having the same issue.

 

[Kevin Marshall]

Unfortunately I never found a real concrete answer. I ended up marking batteries if they failed twice (allowing for one fluke). Two out of the six got marked and taken out of rotation, and the problem seemed to go away. What's odd is that the batteries didn't really seem to have much in common, one was from 2009, and one was only a couple years old. Neither had any obvious damage, and both worked fine on the Dragon (which apparently has a higher power draw than the Epic-W according to Red's white papers). After a week and a half of no issues, we thought we had it figured out, so we decided to put the marked bad batteries on as a test. No problems from either. So I don't know...ghosts?

One interesting line of investigation is the communication pins, both on the batteries and the LEMO connector. There is a magnet as well as pins in the battery that enable RED communication, so it's possible those were faulty in the batteries (or I guess even the battery plate, it was old). It's also possible there's a kink in the short cable that runs from the battery plate to the camera, which would maybe explain why the problem was intermittent, and seemed to correct itself inexplicably, if it got twisted back into a good spot.

I doubt I'll ever know - I haven't heard from the camera owner about any issues since, and he's likely got a cableless WC plate back on it now, anyway.

 

[Neil Abeynayake]

I don't know whether you had seen this before but I posted the following a few months ago:

For Epic-W camera.

Chapter 3 (pages 39 & 40) of your camera operations guide states power requirements for the device is: +11.5 volts to +17 volts DC range and draw a maximum current of 9 Amps.

I.e. when your camera's primary power source or the battery depletes down to 11VDC, the camera will initiate its shutdown procedure unless another source is providing backup power. It will warn you by blinking the power LEDs and changing their color to amber and then to red. That's when the camera would shutdown without further notice.

Older the battery expect the unexpected.

 

[Med D]

Regarding power draw, I wonder if shooting dual format -- RED and ProRes for example -- causes an increase in power consumption. Computing that extra format must use some MIPS and MIPS cost power.