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ESC/Battery Recommendation for Slow RC Research Catamaran

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ESC/Battery Recommendation for Slow RC Research Catamaran

Old 11-04-2014, 06:26 PM
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Eco Aaron
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Default ESC/Battery Recommendation for Slow RC Research Catamaran

Hi Gang,

My first post here but have learnt heaps surfing around (mostly the scale model and ROV forums).

I wanted to ask for some help with choosing some ESCs for a 'first' RC project.

I am building a prototype catamaran platform which will carry a basic bathymetry mapping system (fish finder, transducer, data logger, etc). It'll be about 100m long x 60cm wide (each hull about 20cm wide at widest) and only need a max speed up around 3m/sec (10km/h). Below I have a picture of one hull and the second being put together in the background plus a really dodgey newby Sketchup of the idea.

There will be a motor/esc/battery system in each hull and I'm trying a wacky kort/jet hybrid type setup. The plan is to run it with differential steering (no rudders) to try and keep the hardware simple.

I have some motors on the way. They are 540 brushed T80s with these specs:
  • No load - @ 7.2V 5500rpm 0.45Amp
  • Max Effciency - @ 7.2V 4450rmp 1.38Amp
Regarding batteries to suit, I need duration rather than speed. Would be great to achieve say 2-4 hours of continual use if possible

Transmitter and receiver are Turnigy (9x).

So to where i need help:
  • I am having trouble finding a cost effective (remember this is just a prototype for now) ESC that has BEC and reverse. From what I can tell Anything form about 10Amps and up will offer plenty of room to move; and
  • Similarly, I can't quite wrap my head around my battery requirements to match the ESC, get the couple of hours I'd need and not have the batteries cost the earth!
Any suggestions would be greatly appreciated.

Aaron.

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Last edited by Eco Aaron; 11-04-2014 at 11:28 PM.
Old 11-07-2014, 02:02 AM
  #2  
mfr02
 
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I have some motors on the way. They are 540 brushed T80s with these specs:

  • No load - @ 7.2V 5500rpm 0.45Amp
  • Max Effciency - @ 7.2V 4450rmp 1.38Amp

Regarding batteries to suit, I need duration rather than speed. Would be great to achieve say 2-4 hours of continual use if possible
Call it 2 amps per motor, 4 amps total. 4 hours, 16 ampere-hours total. Or 8AH in each hull, 7AH is a common enough size in SLA batteries, and there should be enough headroom in the number juggling above to let that size be a good fit. Without knowing the voltage, further guesswork is just that. You might run into a problem carrying the weight. Next lightest for capacity is NiMH, then Lithium, but there is an increasing cost penalty the lighter you go.
BTW, 3m/sec is not "slow" for a displacement hull 1 metre long. As to ESCs, mtroniks marine viper 10 are boring enough, they just sit there and work properly. It is more cost effective to get items that will work in the first place rather than cheap items that will need an early changeout, for whatever reason. If you intend to use tank steering, avoid anything that has a brake function, it will simply not work with any form of mixer.
Not familiar with that radio - if it has any form of "fail safe" built in, its best avoided. What is a safe mode for a flyer is a disaster for a boat (plane throttle down - boat full reverse)
Old 03-13-2015, 04:12 AM
  #3  
canabus
 
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Check out Hobbyking for brush ESC, batteries, etc.
With those motors you would require gearboxes to drive say a 40mm x 1.4 pitch prop.
Turnigy radio's are very good but you have to buy the servo's separate(to switch things on and off the small one's are OK and cheap).
Batteries two large capacity Lipo 2S(7.4volt) will give you the run time required(one for each hull will stabilize the boat).
Fail safe Hobbyking have separate one.
I would change to low KV brushless motors (300-400KV) direct drive with solid prop shafts.
Power total 800watts .

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