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Gear / Technical Help => Remote Power => Topic started by: nolamule on June 03, 2016, 01:48:53 PM
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I have a RAVPower 23000 with a d/c to hirose connector for my 744. The battery also has two 5v usb plugs that I have used to charge phones and other things while running the 744.
Would it be advisable to run both the 744 and a USBPre2 off the same battery or is there some weird current issue that I should worry about? I am considering adding a USBPre2 to have the additional phantom channels and for >:D with a small bit bucket.
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You would want to test this at home first as the battery you referncing is probably only a 75Whr battery (23 x 3.7 ~ 85Wh x 90% efficency ~ 75Wh)
The 744T can pull anywhere from 4 - 20w depending on how it's being run (i.e. 4 channels with phantom enabled @ 24/192 would be 20W so lets say 4 channels w/ 24/48 probably ~ 15w)
The USBPre2 is 2.5W (5v x 0.5 A ~ 2.5W)
Total power budget ~17.5w
75Wh battery / 17.5W power budget ~ 4.3 hours total record time
90% efficency is begin generous
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to note the 20W may include running an external Firewire drive so you may be ok - but again you would want to test ahead of time
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You would want to test this at home first as the battery you referncing is probably only a 75Whr battery (23 x 3.7 ~ 85Wh x 90% efficency ~ 75Wh)
The 744T can pull anywhere from 4 - 20w depending on how it's being run (i.e. 4 channels with phantom enabled @ 24/192 would be 20W so lets say 4 channels w/ 24/48 probably ~ 15w)
The USBPre2 is 2.5W (5v x 0.5 A ~ 2.5W)
Total power budget ~17.5w
75Wh battery / 17.5W power budget ~ 4.3 hours total record time
90% efficency is begin generous
Very good explanation. I also use a Sony NP battery as backup so I could pull power on the 744 to get more run time if needed. But would there be any issues with a circulating current b/t devices?
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fwiw, I've not used 744 or USBPre 2, however, I've regularly run MixPre-D (12V) and PMD661 (5V) simultaneously from the same battery (a dual voltage Tekkeon MP 3450/R2 50Wh Li-Polymer) and not experienced any issues circulating between devices.
Past tense because I don't run the Tekkeon MP3450 any more, it failed prematurely after only one set at my last show, then it wouldn't take a charge. It appears Tekkeon no longer sells these and it is out of warranty so I took it apart and found one bad cell. Unfortunately, the exact cells they used in them are no longer available and the closest replacements wouldn't fit the case. This was the second Tekkeon failure I've had, first one happened just outside of warranty when they were still selling them and they grandfathered it sending me a replacement.
Knowing the age of the Tekkeon I carried a Sony NiCad NP1 battery with a battery cup as a backup so little was lost. Just this week picked up a pair of 14.4V 5.1Ah(73Wh) Li-Ion NP batteries and charger for the MixPre-D and will run a small USB battery for the PMD661. The NP and USB batteries both fit in the rig bag nicely and I'll carry the second Li-Ion NP and USB battery in an accessory bag with eneloop "AA"s in both the devices for a quick switch backup or battery swap if needed.
I enjoyed the dual voltage Tekkeon and while it worked it made a nice solution but now in 2016 have decided to skip dual voltage batteries.
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You could use a Remote Audio BDSv4u or BDSv4uh that can supply usb power.
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You could use a Remote Audio BDSv4u or BDSv4uh that can supply usb power.
Sure but USB batteries are a dime a dozen and a battery distribution box is really overkill for only two devices when one one of them is 5V. ;)