Just throwing this out there. My test with a sled of 12 (off-brand) Alkalin=
e D-cells (18V) ran my SD702 with AT3032 microphones for seventeen hours. =
However, don't try this with NiMH D-Cells because the initial voltage (~22V=
) might be too high. For using NiMH, the 10 D-cell sled that Rob has previo=
usly described would be a better option.
John Hartog
--- In "Richard L. Hess" <> wrot=
e:
>
> At 01:10 PM 2009-07-02, Rob Danielson wrote:
>
> >I really don't mind carrying a 744T and a 8 lb. mic rig up the
> >mountain; its the 45 lb. car battery required for several, 12+ hour
> >recordings that hurts.
>
> Hi, Rob,
>
> I have a single Blueshape BMF970 plus the original battery which came
> with my SD-722. I have never run the BMF970 down.
> http://www.blueshape.net/minidv.asp?lng=3D
>
> I also have the little charger for the battery so I don't have to
> charge it on the SD722
> http://www.blueshape.net/minidv_chargers.asp?lng=3D
>
> http://www.sounddevices.com/notes/recorders/powering/power-draw/
> Says that the 744T uses 12 W when recording, so that would imply
> about 4 hours from the BMF970. I _think_ the 722 draws less power.
> The manual claims a run time of about 4 hours from the 4800 mAh
> supplied battery. Since the BlueShape is 7050 mAh that would imply a
> run time of 5.875 hours. Of course, running the battery completely
> flat is not a good idea.
>
> I would suspect that with an external 12 V Li-ion battery (4
> cells-actually 14.8 V) and three of the BMF970 batteries you'd be
> doing real well for much less than 45 pounds. The 12 V external
> battery would permit a bridging operation while changing the internal
> (rear-mount) battery every four hours. I would think with Li-ion
> technology, you could obtain the needed capacity in say a half pound per =
hour.
>
> Unattended 12-hour operation might be a little less efficient as I
> suspect there are some additional losses when using external power.
>
> If you're using the external 12-V battery for just bridging internal
> battery changes you will need to disconnect it because it will always
> charge the internal Li-ion battery no matter how it's wired. The
> wiring depends on whether the unit charges the internal battery when
> the unit is off or on.
>
> In some ways, I lust after a 788T, but the 722 is still rather nice.
>
> >On the other hand, we all look like lazy
> >whiners if seen by recordists a mere 20 years ago.
>
> Indeed!
>
> As to the Zoom H2, I am pleased with it using it for church service
> recording off our sound board.
>
> All the sermons posted here after March 29th
> http://www.trinityaurora.ca/sermons_2009.htm
> Have been recorded on the H2 using its line inputs--after the first
> week or two, we added a pad and our new Yamaha board has an
> individually adjustable output which I intend to use for the H2. See
> http://richardhess.com/notes/2009/04/13/zoom-h-2-line-input/ for more det=
ails.
>
> The June 14th sermon was recorded outdoors with the Zoom near the PA
> speaker using its built-in mics. I was away or it would have been the
> SD off a mixer, but I was visiting my Dad for the last time which was
> much more important. The team came through and got a recording,
> however, that was more than merely useable.
>
> Regards,
>
> Richard
>
> Richard L. Hess
> Aurora, Ontario, Canada http://www.richardhess.com/
> Detailed contact information: http://www.richardhess.com/tape/contact.htm
>
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