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Gear / Technical Help => Remote Power => Topic started by: PH on March 03, 2015, 03:38:05 PM
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Hey, I'm trying to gauge what it would take to build a portable power source my lunchbox. I plan on taping the Dead 50th and want to use my four Forssell Preamps to power the Schoeps and Royer.
Here is the link to what I have:
http://www.radialeng.com/sixpack.php
Specs:
http://www.radialeng.com/sixpack-specs.php
Thanks for any and all ideas.
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You would really need AC power
The external Power Supply supplies the standard +48v Phantom and +15/-15V DC 500 series typically need
It says a current draw of 1.6A @ 30V DC is HUGE -> pulls 48Watts
You could make a DC PS that could supply this but you would need HUGE high current output batteries - lets say the 48V phantom is captured in a 50W budget with 85% efficiency you would need to supply 57.5 W (12V battery at ~ 5A)
This battery would get you 5 hours or so:
http://www.batteryclerk.com/store/p/81203-Enersys-NP24-12T-Sealed-Lead-Acid-AGM-VRLA-Battery.html?cat=Sealed-Lead-Acid&utm_source=google&utm_medium=cse&utm_term=20016&gclid=CIfc-_qTjcQCFS8V7AodqSYApA (http://www.batteryclerk.com/store/p/81203-Enersys-NP24-12T-Sealed-Lead-Acid-AGM-VRLA-Battery.html?cat=Sealed-Lead-Acid&utm_source=google&utm_medium=cse&utm_term=20016&gclid=CIfc-_qTjcQCFS8V7AodqSYApA)
Weighs around 20 lbs
The PS you would need to build would not be cheap either due to the high current requirements at both +15 and -15V
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If you have access to an electric tech or EE then you could have them test your setup under load to see the real world requirements are
It may be cheaper to buy a Pure Sign wave inverter (it is unlikely you will be able to use standard inverters due to noise issues) - these run about $150 or so - this will be less efficient though and would likely require even a larger battery
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http://www.digikey.com/product-detail/en/RP40-2415DGW/RP40-2415DGW-ND/2320821
Here is a 40w recom part at 86% efficient - it takes 9-35v in and outputs +/- 15v at upto 1.333 A
Costs ~$85 for one but u have to buy 4 @ $375
Also this does not include the 48v portion nor any output filtering that will need to be added
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Thanks for the info H2O! I was hoping for a lithium type solution that was relatively simple. I wonder what the chances of them giving me AC power are. Probably not good.
I've been looking for other 500 series racks that are more portable, but haven't been able to find anything.
edit;
It needs to hold four. Two need phantom and two do not for the Royer Ribbon
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Lithium solutions would be very much more expensive ($250+) and would need to be very carefully chosen due to the very high current requirements
Here is an equivilant lithium battery to the one above:
http://www.batteryspace.com/lifepo4-battery-12v-25ah-300wh-50a-rate-with-led-indicator---replace-sla-12v-20ah-lighter-weight-and-higher-capacity----un38-3-passed.aspx
Note you may need to buy a few to cover all three nights as charging times may be in the 10's of hours - or a very high current charger
Phantom power is trivial as compared to to the pull of the preamp circuit