"Steve @ OutdoorFrontiers" wrote in
message ...

"markm4" wrote in message
...

Has anyone ever tried running a higer voltage on a 12 volt motor. Since
I am using 2x 6volt golf cart batteries, I was thinking that maybe I
could get away with 3 batteries (18 volts) on the same 12 volt motor,
and get a little more thrust out of it. What do you all think?

I think that you'll go like crazy....for a little while.

On a different type of motor...

When I was a kid I took apart a couple tape decks and used the electric
drive motors to make model airboats. The more juice I put into the motor
the faster they went. They drained batteries so fast though that I never
really noticed any overheating of the motor. Heat is the main killer of
electric motors.

Basically the motor is built such that it can handle the total electrical
power Volts X Amps going through it. The size of the wire and the number of
wraps in the windings are factors in this. Typical engineering for this
type of application is atleast 1/3 safety margin. So in theory given that a
12V battery at full charge puts out at about 13.5 volts and a minimum 1/3
safety margin would be 13.5 X .66apx = 22.49apx volts. Now even given a
liberal safety margin built into the motor you aren't quite up to the 26-27
volts that two fully charged batteries in series would put out. Also,
figure that even if you could push the safety margin exactly (which is not
practical) the motor is not designed to handle that for an extended time.

Remember when we talked about the size of the wire and number of wraps in
the winding. Well the wire has some resistance to the flow of electricity.
It tends to get warm, but its designed to radiate off the excess heat. If
it gets too hot it will melt. By pushing your safety margins the motor will
accumulate more heat than it is capable of shedding. This will cause it to
over heat and break down. The wire may melt, but also many electric
trolling motors have more than a simple motor and voltage (speed) control).
Those other components are designed to operate within a certain range and
going otuside that range will fry them.

Now add one more thing. With trolling motor manufacturers each pushing to
have the better motor than their competitor, the better price, and the
better profit margin. They probably didn't build them with the 1/3 general
engineering safety margin that you might expect. Honestly, all they have to
do is get them to last until the end of the warranty.

If I didn't care about the life of the motor (like my old tape recorder
drive motors) I might try it, but if you are doing it because you can't
afford a bigger and better motor then I would err on the side of caution,
because you might find yourself with nothing.

I think that you'll go like crazy....for a little while.

--
Bob La Londe

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