At 9:35 AM -0700 8/12/09, Aaron Ximm wrote:
> Hi,
>
>Can anyone give me the quick run down on what's needed to run a Sound
>Devices 7 series recorder off a 12V (?) lead acid battery?
>
>I need to do some uninterrupted recording on the order of 24-28 hours,
>two channel, probably 24/44, with a 722, providing phantom on both
>channels. As are as I can tell I will need a pretty beefy battery --
>anyone have field experience on what I really need? I was thinking a
>26Ah battery would be conservative. Not to mention ridiculously heavy,
>but I don't need to transport it into the back country, so that's OK.
>
>My specific questions are:
>
>Any guesses on the capacity I should really pursue?
Hi Aaron--
In warm weather, Rich's 23AH AGM battery will run two 722's for 10-12
hours and pull the battery down to 50% (recommended minimum). If you
can find an AGM in the 15-23 AH range, that should do it with some
surplus which is good to have handy for cold weather.
You _might_ get by with a 14.4 volt sled of the 10ah NiMh batteries
that are available. I can get 12 hours from mine but I have to use my
Maha charger, not just the "smart" chargers that run $30-50 they sell
for sleds. On those, more like 8 hours.
>
>Is there a commercially available power cable adapter that terminates
>in the appropriate connector for the 7 series recorders, and has
>spades on the other end for batteries?
Not that I am aware of and it not a super easy solder job, but
doable. Look in your manual or on the SD site and solder one up
according to their pin suggestions. Both Rich and I have our cables
wired for operation and charging-- this works best for power
switch-over issues.
>
>Do I need a lead acid battery charger? I have a lead on some very
>affordable ones, but is this a must- or a nice-to- have?
I use non sealed garden tractor batteries but the sealed ones are
better and much safer. His 23AH is not too bad compared to what I'm
accustom to. ;-)
>
>Any tips/pointers much appreciated. :D
Rich has circuit that he made that disconnects the large, AGM battery
after it reaches a designated low voltage. Then the 722's internal
battery takes over through self power-down. If you don't want to mess
with this, a larger external battery is pretty good insurance. SD
also has info about a circuit they suggest in their forum or contact
Nick Stage. I just use a larger battery, myself. BTW, my 744T did not
have the switch-over problem until I got the hardware upgrade. I
feared this might happen based on Dan's and John's reports. :-( Rob D.
>
>Thanks,
>aaron
>
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