Surface Raft – Control / Electronics

From 04 20 2012 Presentation to Cortis

Revision: There will be four thrusters, not two

Thrusters

  • Four Thrusters (Two pairs)
  • 500 GPH Motor Cartridge from Johnson Pump 12V
  • Max amp draw: 2.5 A

Question: How many batteries do we want to put on the raft ?

Assume the Wild Thumper is .95 efficient.

Tenergy NiMH Battery

  • ? Batteries
  • Series? Parallel? We want Parallel to increase the capacity, not the voltage.
  • 7.2V
  • ? x 3000 mAH

P_max = (2.5A)(7.2V) = 18 W/thruster

P_dissipated= 1.052*18*4 = 75.744 W
Thrusters in series (pairs) = twice the resistance, same I

Pairs in parallel

I_max = 2.5A

Time / battery = 1.2 hours

For every 1.2 hours of operation, need 1 battery.

Goal: 5 hours

Use 4 batteries.

Dimensions of batteries: 5.39″x1.87″x0.95″

Dimensions of Wild Thumper: 4″ x 2 3/8″ x 1 1/4″

Picking out the Case …

Storm Case USA Pelican Case im2050, Dimensions                        Inside – 9.50″L x 7.50″W x 4.25″D                 Outside – 11.80″L x 9.80″W x 4.70″D Electronics 1 35.75 http://www.stormcasesusa.com/pelican-case-storm-im2050.htm
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