At 4:29 PM +0000 10/27/08, John Hartog wrote:
> > Are we sure that simulating an external power disruption will produce
>> reliable results?
>
>Rob,
>
>I am not completely positive, but in the few times I have tested it,
>pulling the plug on the battery pack results in a proper switch over.
Seems risky/illogical doesn't it-- especially compared to the
functioning hardware and firmware made before
improvements/adjustments were made? Perhaps the solutions for
external powering, auto-shutoff and file writing became conflicted.
Ironically, I've used every type of external battery powering except
LiOn and have had no problems with any of the functions. SD's
effectively making long-duration recording a low priority. They might
need to re-examine the balance of features in the firmware as I doubt
they want to provide global hardware exchanges.
> > So, if you connect an _external_ Li-On battery, the automatic
>> switch-over works correctly on your 702? All other external batteries
>> you've tried do not?
>
>Maybe it is a stretch to assume Li-On will work properly. I have not
>tried Li-On. After experiencing the failure, Dan sent his 744 in to
>Sound Devices and they gave it clean bill of health suggesting Dan was
>using the wrong batteries. Though I have not sent my 702 in to be
>checked out, SD has explained that the switchover function works fine
>for them on the Li-On packs they use.
>
>> Sorry, I should probably recall from earlier posts, does this
>> work-around enable you to reliably make long (~12 hour) duration
>> recordings on your 702? What is your work-around?
>
>Basically do not rely on switchover to the attached battery, and make
>sure your battery pack is sufficient to power the recorder for
>sufficiently more time than you than you need. Set the recorder to
>place tracks at the maximum file size you are comfortable losing: I
>use 1GB intervals and assume my memory card is that much smaller than
>actual. Only the final file will be corrupted and lost.
We shouldn't have to be hedging losses on $2000+ recorders.
>
>I have yet not tried a 12 hour recording with my 702. My largest
>battery pack so far (8 D cells) is not sufficient - only reliable for
>about 6 hours I think. I have been exploring the options for larger
>packs.
Which, in practice, can mean using batteries with twice the needed
capacity to have a reliable system for long duration recording. I use
the small internal LiOn battery pretty much only for extra protection
for automatic shut-down when my external battery runs out. A number
of times I have used the 744T with no internal battery and it still
shuts off without loss using only the external battery.
In my experience, LiOn battery output becomes too variable to rely on
for long duration recording. I use a 12 hour NiMH battery pack when
I need 6 hours and a 48 hour lead acid lawn tractor battery when I
need 24 hours. The conditions and rates of power required seem to
vary too much to identify/match needs closely. Even 50% extra power
can turn out to be too little.
>
>> Seems like it could be time for a collective request to SD to address
>> some of their recorders' difficulties in making long-duration
>> recordings in the field. I'm curious if there are other
>> hardware/firmware patterns we could gather for a collective email.
>
>Good Idea.
If we can get the signatures of 20+ SD owners, it might help. I'll
draft an email to Jon Tatooles if we get a enough interest and some
well-organized clues to possibly help their efforts. It will be a
pleasant request. Rob D.
>
>> anyone else besides me NOT experiencing problems with external
>> batteries for long recordings with their 7 series recorder? Rob D.
>
>That would be good to know.
>
>John Hartog
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