T-Pain Is On A Boat: Re: [Electric Boats] Re: Motor control without a controller

Monday, October 8, 2012

Re: [Electric Boats] Re: Motor control without a controller

sounds a lot like the BIG micro-switch arrangement used in model boats years ago,

first switch doing 2 7.2v or 8.4v nicad packs in parallel, second a pair of the switches joined to flip the packs to be running in series at 14.4 or 16.8v.. all run by cam on top of a servo.

small capacitors used to take the brunt of what'd be arcs-n-sparks, about same as motor caps to reduce RF noise from the older RC model motor's brushes. it was a simple 2 speed arrangement and there was a way to connect up a reverse very similarly to the backside of the same servo-cam.. been a long time since I was playing with that stuff.
no doubt at high current, stuff is gonna want to weld itself! my little buzzbox welder is taking 120v 15A AC, transforming it to 40v DC maybe 25A to weld steel with.

idk for not looking around a whole lot, but robotmarketplace site has some pretty hefty ESC's there, like: http://www.robotmarketplace.com/products/0-OSMC.html

they claim couple of those in parallel can handle 300A continuous, with a single being able to absorb up to 400A on a short term burst. 24v at 150A with 75% motor efficiency calcs to about 3.6hp and 2700watts, double that on 48v, 7.2hp and 5400watts. seems quite a lot for a 220 dollar controller, double all that again with a pair of em parallelled together, for near 11,000 watts and 14.5hp, for 48v with maybe 500 bucks spent? idk, seems like an invite to hook up an e-tek in a little runabout and try some wakeboarding, darn near.

--- On Mon, 10/8/12, CHAS <okawbow@hotmail.com> wrote:

From: CHAS <okawbow@hotmail.com>
Subject: [Electric Boats] Re: Motor control without a controller
To: electricboats@yahoogroups.com
Date: Monday, October 8, 2012, 7:53 AM

--- In electricboats@yahoogroups.com, "inganear1" <inganear1@...> wrote:
>
> If I recall sometime ago someone in the group made a busbar type of arrangement to control voltage as a speed control for their system not using the normal electronic controller, or proposed anyway, can't remember exactly.. I would like to make such a system for a backup since I use 6 volt batteries in my 48 volt system on one of my boats. Can someone point me in that direction..
> Dave K
>
I just launched my Privateer 26 sailboat with a basic electric drive to get me out of the marina. I didn't buy a controller yet, as I wanted to test out the system before committing to 48 or 72 volts. I use a Mars ME0709 motor with a chain drive 2.2 reducer to the original 2 blade 13lh12 Michigan Sailor prop. I have 4-12v deep cycle batteries in series. I tap off a 24v lead to a 200amp marine battery selector switch for No.1, and tap off 48v for the No.2 terminal. I blocked off the "both battery" setting on the switch. The power lead is then run to a reversing contactor (the type used for linear motion control, in-off-out), and then the motor. I have a simple on-off-on selector switch in the cockpit to control the reversing switch.

This system works fine for me. There is no problem with arcing, and I have a 2 speed drive, which gets me out of the marina into the lake. The 24v setting is plenty fast for my in-marina needs. Probably about 3 mph. The 48v setting will do nearly hull speed. The boat is 6500 pounds.