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Very short low battery warning on Sony HXR-NX5U with NP-F970 and NP-F770 batteries

March 21, 2010

Hi All

I usually don’t let batteries run completely flat on the camera while shooting, but a few days ago I noticed a low battery warning on my NXCAM.

I assumed that I would get perhaps fifteen more minutes shooting and another warning before the battery actually died, but within about a minute of getting the warning, in the middle of a clip, I had a complete unplanned shutdown. The battery was a 6 week-old Sony NP-F970 InfoLITHIUM battery that had been fully charged on a Sony charger the evening before.

When I fitted a full battery and restarted the camera, the normal clip recovery screens appeared, with the option to recover the interrupted clip first to the SD card, and then to the FMU (I was shooting 1080/25p FX footage to both simultaneously).

However, the clip was NOT recovered to either storage medium.

This is the first and only time I have run a battery flat in the camera, but it worries me that

a) the warning time given is so short


b) the clip interrupted by a battery running flat was NOT recovered.

ADDITIONAL NOTE: In order to see if the short battery warning I obtained once when shooting with the NP-F970 was an anomaly, I inserted the (fully charged) NP-F770 battery that came bundled with my NX5U with the aim of shooting until it went flat to monitor performance.

I removed the FMU128 unit and shot 1080/25p FX footage on to a blank 16GB SanDisk Extreme Class 10 card. At the beginning of shooting the camera’s LCD told me I had 95 minutes of battery power remaining at that rate of use (the blank card had space for 85 minutes worth of footage). After about an hour of almost continuous random shooting (two long clips and three short ones) the card showed that it had 24 minutes of footage remaining, and the battery 25 — the battery meter had thus over-estimated remaining battery power by about 9 minutes at the start of shooting.

However, a low battery warning suddenly appeared at that point and the camera shut down within about 5 SECONDS of it appearing — in other words, it went from showing 25 minutes of battery power remaining to turning itself off in a matter of seconds.

This time, unlike with the NP-F970, the clip that was interrupted by the battery going flat was present on the camera media when I started up.

This is pretty worrying — Sony’s InfoLITHIUM batteries are meant to give extremely accurate information on remaining capacity to the camera. Maybe the NX5U is not properly calibrated to use this information properly?

I would appreciate comments from other NXCAM users who have run a battery flat while shooting.



7 Comments leave one →
  1. March 22, 2010 12:38 am

    Thank you for all this Adam

  2. Marshall Smith permalink
    March 31, 2010 4:19 am


    Out of curiosity how did you go about charging the batteries. Did you quit charging once the light on the charging unit went off or did you top off the battery as noted in Sony’s literature?

    I realize that the batteries are intelligent but am wondering if the new charger leaves the battery thinking it has more charge than it actually does if one doesn’t “top it off” a described in their manual.

  3. May 5, 2010 6:01 pm

    I did a shoot this weekend. With both F770 and F970 batterires. I was able to get within 12min remaining on the F770 before i ended the recording and switched out the battery. Did not want to have a shutdown. However i noticed when inserting a fully charged F970 battery. It displayed 620min battery remaining.. Which i was happy to see at the time but couldnt help but think that was too good to be true. Once it reached around the 300min remaining mark it gave me the flashing yellow battery low warning and within seconds it shut down. I’m not sure if its because that F970 battery was a rental that came with a Sony HVL light. Perhaps because it was in such heavy use over the years. Either way i found it strange that it said 600min remaining.

  4. Harry permalink
    February 19, 2011 1:25 pm

    I just had the same experience, I have a new np-f970 battery freshly charged. it had 84 minutes left and dropped dead? in the middle of a shoot. Now when i put it in the charger the charger just blink fast and it wont charge. ?

    • adamwelz permalink*
      February 19, 2011 2:16 pm

      Sounds like a faulty battery. Did you drop it? Contact Sony.

  5. tom hardwick permalink
    April 30, 2011 2:42 pm

    I’ve noticed that Sony’s info-lithiums ‘learn’, so if they’re only ever used on the NX5 (say) then their readout is pretty accurate. But if you take the battery off and use it to power a lamp for instance, then it’ll take a few discharge/charge cycles on the NX5 to gets its ‘info’ accurate again.


  6. tom hardwick permalink
    September 6, 2011 1:13 pm

    It’s a bit of a heart-stopping moment at a wedding. I’d already filled the 16gig card A with 1080/50i, the Sony NX5 had automatically switched to card B and all was well. Halfway through the groom’s speech my NPF760 battery powering my NX5 suddenly signalled ‘battery low’ with a flashing battery icon mid screen. I didn’t know if this meant I had 5 minutes left or 5 seconds, so, with spare battery in my right hand I let the battery poop out and the camera shut down. You never know – it might happen between speeches …

    Click, slide, slide click, on goes the fresh battery. I turn on the camera again but all sorts of distress warning symbols appear on screen, one of which was, ‘cannot record to card B, corruption’ or words to that effect. Speeches continue uninterrupted of course, so ever the pro I replace the SDHC Transcend 16 gig card and press the NX5’s little button – record to this new card B. This all takes valuable time.

    Speeches end and I take the opportunity to replay the card in camera. Nothing. Cannot replay HD movies, corruption. Did I want to try a repair? I sure did, and tapped the yes on screen. Still nothing. All is not lost, I’m a two camera man and the backup has continued over the join but in long shot, its audio gathered from its own top-table radio mic.

    At home on Sony’s Content management Utility (CMU) a warning appeared: ‘HD movies that do not have management information have been found. HD movies without management info cannot be recognised by the camcorder but can be imported by the PC’. HD Movie Recovery appeared in the CMU.

    The results are usable but not right. There’s no audio waveform associated with these long speeches and as soon as I try and play the timeline Edius 6.03 crashes. Today I’ve had more Edius crashes than years of Premiere 6.5, which is saying something.

    I tried exporting the file to tape, to file, to DVD – all crashed Edius.

    I then unlinked the audio from the video (I’ll try anything), changed the project settings to SD 16:9, and moved audio and video apart on the timeline. Relief – I could now capture it to my DSR11 as the timeline played. There’s a lot of syncing up to do later, but the moral is this:

    Don’t let your battery poop out on you if you’re file-based recording. Leastwise not on a Sony NX5.


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