At 2:12 PM -0400 7/2/09, Richard L. Hess wrote:
>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>http://www.blueshape.net/minid=
v.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.blueshape.=
net/minidv_chargers.asp?lng=3D
>
><http://www.sounddevices.com/notes/recorders/powering/power-draw/>http://w=
ww.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 h=
our.
>
>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.
Hi Richard--
I'm definitely open to ideas. There's no electricity for charging
unless I lug a sizeable solar panel. Rich Peet uses an 80 watt panel
for his 722 (I think he figured the 722 consumes 18 watts when
running). My 744T and MP-2 might pull close to 30 watts. Rich's is a
fixed station. Solar panels would be pretty heavy addition for a 3-4
day, remote set-up.
I should have gotten longer recording time from virtually all of the
batteries that I've tried. For recharging applications I think its
suggested that the batteries be depleted no more than 50%. Fairly
consistent with your computation, I get 10-12 hours on a 10 AH 14.4v
battery sled made of NiHH cells running the 744T/MP-2. I'd need 4 of
these sleds for 3, 12 hr nights, so the weight works out about the
same as one large 12v AGM battery. SD suggested using a
regulator-like device to help with the shut-down/file loss bug, but
its also solved by using the over-sized battery. I hate losing
recordings and the extra sweat makes me feel like I'm accomplishing
_something_ even if just aerobic exercise. ;-)
>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>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/>http://richa=
rdhess.com/notes/2009/04/13/zoom-h-2-line-input/
>for more details.
I'm experimenting with the H2 line input now. Mike sent me a test
I'll listen to too. I now see why Curt found the default level of
"100" on the H2 to be more sensitive than most -10dB line inputs.
I'll see if I can get a sense of how limited the dynamic range is as
a result. Have you determined for sure whether the line input gain
is downstream from the A-D?
>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.
Sorry to hear about your Dad. Quite a few of my friends are
experiencing this stage in life. Rob D.
>
>Regards,
>
>Richard
>
>Richard L. Hess <richard%40richardhess.com>
>Aurora, Ontario, Canada
><http://www.richardhess.com/>http://www.richardhess.com/
>Detailed contact information:
><http://www.richardhess.com/tape/contact.htm>http://www.richardhess.com/ta=
pe/contact.htm
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