FS7: lowest voltage before FS7 dies?

L

LennyLevy

Veteran
I use batteries which don''t register on the FS7's "time left" viewfinder readout but I do see the current voltage reading. Does anyone know at what voltage level the camera will finally shut off? (For recording of course)
Its hard to find this information and actually I'd like to know it also for the Odyssey 7Q, my trusty old EX-1 and TV Logic as well.
 
In the System menu of the FS7 all kinds of voltage threshold are set; for instance Camera Battery Alarm is by default is set to 3% for "battery empty", but you can raise it to 7%. Similarly, for Camera DC in Alarm, it's 11V by default.

Piotr
 
I know I can set the alarm for where I want it but what about when the camera actually dies. I can test this but its a PITA because you have to keep watching it.
 
With a Sony BP-U30 battery installed, the recording stopped at 13.3V and the camera shutdown completely at 10.2V. The voltage is available on the STATUS screen (press the STATUS button until battery info comes up). The voltage drops faster and faster as it depletes, so not linear. From 14.1V to 13.3V was ten minutes recording time.

You wouldn't need to observe the camera for the entire time of a fully charged battery to do your testing. You could deplete a battery and then give it a short charge and run your test. I just clipped a smaller camera so it could record what was going on with the STATUS screen and after the FS7 died I checked the other camera's footage for the timelines and voltages. I also read out my BP-U30 with a voltmeter at the start and it showed the same amount as the camera did, but once the camera shut down, at 10.2V, I re-checked with the voltmeter and that battery was 0V, flat dead.
 
14.4volt batteries are often built around 4 x 3.6 volt Li-ion packs. 4 x 3.6 = 14.4 volt. Each pack fully charged come up to 4.2 volt. 4 x 4.2 volt = 16.8 volt. A voltage you are likely to see from a battery straight off the charger. So as not to damage the batteries and to ensure you don't go below the minimum battery levels you will need to re-adjust the two Low Voltage levels in the FS7 menu.

Seeing that most of the batteries use 3.6 volt cells that are nominally considered discharged at 3.0 volts one can take it that 4 packs x 3 volt each means a battery pack is "dead" at 12 volts. If we give this figure a 10% safety margin we can say each pack is flat at 3.3 volts. 4 x 3.3 = 13.2 volts. On that basis Low Voltage Alarm #2 could be set at 13.2 volts. If we now calculate a 15% level for Low Voltage #1 this would be 3.45 volts per pack x 4 giving us 13.8 volts. Running 14.4 batteries at anything less than 12 volts can permanently damage them in the long run. Worse still there is a chance they can go "reverse polarity." This can cause Irreparable damage to the battery and can even damage equipment. Beware running Li-ion batteries below their terminal voltage levels.

http://batteryuniversity.com/learn/article/confusion_with_voltages

I have mine set at 14 volts for Low #1 and #13.5 volts for Low # 2 and find I am getting plenty of warning time to enable me to pick the best time for a battery change.

Chris Young
CYV Productions
Sydney
 
Last edited:
Straight off the charger this Sony BP-U30 (which says 14.4V on its label) read 16.3V on my meter, so that's pretty close to your numbers Chris. My tally light went from steady red to flashing red for several minutes prior to the recording stopping due to low battery.

Mark
 
If you're asking to figure out how long to try to run the battery, you may find another issue -- the rate at which the voltage is dropping when the camera stops recording. Most batteries stay within their operating range for most of their usable running time, but when they start dropping they may drop very fast. Particularly older batteries. With a new battery you may get enough time with the battery warning to record the end of an interview answer - but later in its life you may drop to just a few usable seconds in the Warning mode - or possibly a cutoff without warning. As I recall, Convergent-Design tends to try to have products which will continue running after a camera may have stopped recording (ie continue to operate at a lower voltage). This may be a good thing (protecting your recording) or a bad one (because it may drop the battery voltage too low - see post #6 above regarding reverse polarity.)
 
You must log in or register to reply here.
Back
Top