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Re: 744 battery switchover test

Subject: Re: 744 battery switchover test
From: "John Hartog" hartogj
Date: Mon Oct 27, 2008 9:29 am ((PDT))
> 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.


> 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.

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.

> 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.


> 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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