Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: MartinH-K on March 25, 2009, 11:55:18 am

Title: Unusual elec diagram needed
Post by: MartinH-K on March 25, 2009, 11:55:18 am

A suggestion (very clever one actually!) has been made here concerning powering my huge HMS Hood. The suggestion was that I investigate using the electric engines from a mobility scooter...
I have a couple of the engines but I could use some help in cobbling together the circuit diagram to incorporate 12 volt batteries and a general speed/direction controller.
Thanks guys
Martin

Title: Re: Unusual elec diagram needed
Post by: malcolmfrary on March 25, 2009, 02:35:52 pm

If the motors are brush types (two wires) then look at
http://www.modelboatmayhem.co.uk/forum/index.php?topic=6169.0
where you will find something to fit.
The only difference between a "normal" setup and yours is that you have larger motors, with a larger current draw.  Once you know what that current is, you can figure out which ESCs you need.
To control the ESCs, either by radio from shore by someone with a sense of humour, or use a servo tester as a control source instead of the radio.

Title: Re: Unusual elec diagram needed
Post by: MartinH-K on March 25, 2009, 03:08:59 pm

Its a manned model- I'm sitting in it. O0

Title: Re: Unusual elec diagram needed
Post by: Arrow5 on March 25, 2009, 03:17:50 pm

If you find a repair shop for the disability scooters they will maybe have spares and bits`n pieces including the manual controls. I`m on the case, got a place about a hundred miles from here that advertises all sort of things, due a trip soon.  Also found cheaper supply of the makings for crew, will PM when they reply with exact prices.

Title: Re: Unusual elec diagram needed
Post by: MartinH-K on March 25, 2009, 03:49:23 pm

Thanks Dunc... The mobility place I checked offered me two engines plus a control (forward/backward knob) for £15.

Title: Re: Unusual elec diagram needed
Post by: andyn on March 25, 2009, 05:06:44 pm

How about just a servo connected to the top of the knob with a ball joint?

Title: Re: Unusual elec diagram needed
Post by: funtimefrankie on March 25, 2009, 05:24:06 pm

Will these be proportional or just on and off (forward/reverse).

Title: Re: Unusual elec diagram needed
Post by: MartinH-K on March 25, 2009, 07:08:37 pm

Need to put a variable resister in the loop to control speed... {:-{

Title: Re: Unusual elec diagram needed
Post by: malcolmfrary on March 26, 2009, 10:54:56 am

Thats why I suggested using ESCs of suitable size with a servo tester as a control.  With that arrangement you do get full proportional control.  The ESC wants a signal from a radio - the tester provides that signal.  It doesn't really care whether its driving a servo, a switcher or an ESC, it just provides a signal that varies in accordance with the knob on the front.
As an alternative, PMK has put a diagram of a suitable unit in his thread at
http://www.modelboatmayhem.co.uk/forum/index.php?topic=16005.0
which he intended as a servo controller, but will be just as good as an ESC controller.
The advantage of using ESCs is that you would be using a standard technology, which is drop-in replaceable should the need arise.

Title: Re: Unusual elec diagram needed
Post by: FullLeatherJacket on March 26, 2009, 01:56:14 pm

This'll do yer; it's built and tested for a tenner.
http://www.action-electronics.co.uk/pdfs/P22.pdf
Not sure about the motors, although one of our customers uses motorised golf-caddy motors ("MOCAD") with a standard ACTion unit.
FLJ