martyman

iTrader: (2)

Hey all !

I am shopping for Brushless set up for my boat. this is what i have come up with .

the jet drive unit im installing has a max RPM 20000
So, 2700KV @ 7.4v = 19980 RPM
I will run 2 1500mAh 7.4v 25c 4s in parallell
So, if discharge A=(mAh)/1000 x (c)
3000/1000 = 3x25 =75A
do i need a 75A or higher rated ESC ?
i am looking at a 35A ESC With a 5v 1.5A BEC
Will this work with a 2.4 ghz receiver and digital servo? or do i need a BEC with 6V 1.5A.

Here are the items:

Motor
KV2700 Brushless in runner RC Motor for RC boat(WaterCooled)
Rotational Speed 2700Kv (rpm/v)
Input Voltage 7.4v- 14.8v

Batteries
2, 7.4 v 1500 mAh Lipo4s 25c, run in parallel, @ 3000 mAh output.
lipo
Size:71.4mm x 35.5mm x 19.2mm
Battery Capacity:1500mAh
Battery Voltage:7.4v

ESC
35A brushless boat esc with bec 6v/1.5A ,built in cooling jacket.
Continuous Current:35A;
Burst Current:190A;
Working Battery Types:4-12 cells

2.4 ghz 2 channel transmitter/receiver

servo
speed 0.14 /torque 75 oz/in @ 6V
Size:40.8x20.1x38mm
Weight:52g
Operating voltage:4.8V~6.0V


Any advice ?
Thanks in advance

Shev

iTrader: (13)

You're off to a good start.

I've just finished my jet drive NQD Tear into boat.

It's running the same speedy as you - it is fine.
7.4v is what I'm also running, I've tried a couple of configurations with two batteries, and different sized batteries, the main issue is balance. Just get it run true.

Your motor may be a little underpowered. My boat is quite small (40cm). An idea is around 4800Kv for 7.4v and 3000Kv for 11.1v - they equal out to be the same. An easy option might be for you to run 11.1v instead of the 7.4v.

Definately use water cooling - how ever it may be. I use the 4800Kv water cooled inrunner from hobbyking. It is a 2.3mm shaft. You may need to make your own water pickup to put in the jet drive. And of course, don't forget the outlet.

Servo is up to you, as long as it works.

This info will also depend on what kind of boat you are running. Jet ski? Boat?

Hope this helps.