"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."
Here's my "back of the envelope" calculation.
The Sound Devices folks say the 722 will record with phantom power on for a=
bout four hours when using the standard 4400 mAh, 7.2 V Sony-compatible bat=
tery. That battery has (4400 mAh * 7.2 V) =3D 31.7 Watt-hours capacity. T=
hat's 8 watts consumed per hour of recording.
To record 28 hours using the 722, you'll need (8 watts per hour * 28 hours)=
=3D 224 watt hours
Xantrex makes rechargeable lead acid power packs that offers 12V DC and 120=
V AC outlets. The Xantrex XPower Powerpack 300 Plus has a 20 amp hour seal=
ed AGM battery. 20 amp hours * 12 V =3D 240 watt hours, enough for 30 hour=
s of recording with the 722.
The Xantrex XPower Powerpack 300 Plus costs about $125 from online sources.=
It weighs 20 lbs, so figure about $25 to ship.
The XPower battery also can jump-start your car, and inflate its tires!
--oryoki
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