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I am trying to make a mobile computer for my Raspberry Pi. The problem here, is powering the Pi, screen AND the USB hub from the same power source. I have bought this: http://www.amazon.com/Lumsing-11000mAh-External-Battery-Charger/dp/B00B9BUZW2/ref=pd_sim_sbs_cps_2 external battery pack.

The maximum output from the battery pack is 2.1A. I am trying to boost voltage from 5v to 12v while drawing 5A to power an LCD controller board. This is the voltage converter: http://www.amazon.com/gp/product/B00COD8PDU/ref=oh_details_o02_s00_i00?ie=UTF8&psc=1 (Don't worry, ill attach a good heatsink with a small fan)

Will the 2.1A output max be good enough to boost from 5v to 12v @ 5A? i am also wanting to calculate how long this thing will run from a single charge on the pack. Current draws for each: 750ma - Pi ??? - LCD controller varies maybe 1-1.5A - USB Hub.

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No. It is rated at 5 V, 2.1 A. That is 10.5 W. If you want 5 V, 5 A, that is 25 W. You can't create power in a switching regulator.

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  • \$\begingroup\$ So, what would the minimum current and voltage be to drive something like that at 12v and 5A? Second look: I meant that I was connecting the 5V battery pack with 11Ah capacity to a switching regulator to output 12v and 5A \$\endgroup\$ – Jay Bhagat May 13 '13 at 16:31
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    \$\begingroup\$ If you need the switchin regulator to output 5 amp at 12 volts, it will require at least 12 amps at 5 volts input. Power in = power out + losses (inefficiency). \$\endgroup\$ – Peter Bennett May 13 '13 at 17:00
  • \$\begingroup\$ Thanks! So I guess a buck converter is in order instead of a boost. I dont think i want to wear out my source of power that quickly (assuming 1-2Ah per cell in parallel). I am trying to get at least 3 hours out of this, so I need about 80V input, right (for the buck)? \$\endgroup\$ – Jay Bhagat May 13 '13 at 17:09
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    \$\begingroup\$ The battery pack you suggest is, in my opinion, totally inappropriate for your application. It is intended to be charged from USB charger, and to provide power to several USB devices (and doesn't include a charger). Although the DC/Dc converter you suggest says it can deliver 5 Amp, it is also rated at only 30 watts, so it cannot deliver 5 Amp at more than 6 Volts. - the 5 Amp at 12 Volts you want is 60 Watts. \$\endgroup\$ – Peter Bennett May 13 '13 at 17:09
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    \$\begingroup\$ Amazon says that particular DC-DC converter is not available, so I suggest that you look for another that has a suitable power rating. Whether you use a buck or boost converter does not change the fact that Power In > Power Out. I suggest that you start with a 12 volt, 20 Ah (or more) battery - a DC-DC converter would still be required if you need a regulated 12 volts. \$\endgroup\$ – Peter Bennett May 13 '13 at 17:17

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