Using Trolling Motor as an outboard

[BHOFM]

Originally Posted by matrix

Exactly, no gas and many lakes (e.g. reservoirs) do not allow gas engines...

Sorry, I didn't understand your comment about the battery. Can you tell me where you got the battery and what brand? Was the battery only $24? if so, Wow...

A place called Battery Outfitters, local company has over
stock or slow movers that have been on the shelf and they
discount the price. They call them Blems.

Yes it is new, it has a two year replacement warranty.
The label only says "Heavy Duty".

http://www.batteryoutfitters.com/

I wanted a small, low profile and this just fit the bill.
I thought if needed I could add a second one, but it
seems fine with the one.

[BHOFM]

Originally Posted by pistnbroke

Your quote of 450 ah is wrong you have quoted the cranking amps ...Look for the marking RC which is reserve capacity ...how long in minutes it will supply 25 A .....typical for a small battery is RC 60 min dont run it down below 10.8v and charge as soon as you can .
remember the difference in weight between a 30ib and 55ib thrust is minimal but you might need it one day ..
It looks like Min Kota have revised there range but have sold the tooling for the old ones to china ..just bought a 86 lb thrust 24v for $us 160 ..you can always run it on 12 .....i force was the brand.

You are right, my bad. The label has been replaced so I
don't really know all the spec's. I have been looking for
a small V meter to take on the boat and get some info
for people.

[Stumble]

After doing this, my recomendation would be to buy the largest 12V motor you can, even in a small boat. The reality is that this is at best a marginal option for limited use, and the larger engines give at least some options. The other thing to remember is that these engines will drain a 75 amp hour deep cycle battery down to 50% in 60-90 minutes. This is the threshold for deep cycle batteries, and leaves you no room for running instruments, lights, whatever before you start doing damage to the battery. Finally even a small battery + the trolling motor is going to likely weigh MORE than just a small outboard+gas. So the only advantage in weight is the ability to multi-purpose the battery for more than just lights and electronics.

Like I said I love the system and it works ok for me, but my needs are very limited, and I still have the gas engine at the dock for when I need it.

[BHOFM]

Originally Posted by Stumble

After doing this, my recomendation would be to buy the largest 12V motor you can, even in a small boat. The reality is that this is at best a marginal option for limited use, and the larger engines give at least some options. The other thing to remember is that these engines will drain a 75 amp hour deep cycle battery down to 50% in 60-90 minutes. This is the threshold for deep cycle batteries, and leaves you no room for running instruments, lights, whatever before you start doing damage to the battery. Finally even a small battery + the trolling motor is going to likely weigh MORE than just a small outboard+gas. So the only advantage in weight is the ability to multi-purpose the battery for more than just lights and electronics.

Like I said I love the system and it works ok for me, but my needs are very limited, and I still have the gas engine at the dock for when I need it.

You have hit the nail square on the head.

One more point, the battery takes up about the same
amount of room as a 2 gallon gas can. Important on
a small boat like mine. Also being able to place the
battery at the best location for trim of the boat.

On the lake, without tides and such it works very well.
And at a much lower cost than an outboard.

I have been using mine a little over a month, fifteen or
so outings. I am 100% pleased, and if I had it to do over,
every thing would be done the same.

[PAR]

The biggest 12 VDC is about 55 pounds of thrust or around 2/3's a HP.

[pistnbroke]

I have an empty jetski which I run with a 25 hp outbard ..but I bought the 86lb 24v trolling motor to put on so I can use it on the " electric only lakes" and wind up the patrol gastapo real bad ..I have enough trouble with the water police o a normal river who think its a jetsiki !!!
Whilst the biggest 12 Minn Kota is 55lb I am not convinced they dont just run them on 24v and call them 80 lb !!!

[EddieWeeks]

I have lots of experience with trolling motors on unmanned survey boats.

Most trolling motor props have a pitch of around 4 inches. Once your up to speed, the prop slip is fairly low.. If I were you I would just run your 30lbs
on 24 volts not full power at first. I don't think you will hurt it. Its water cooled it you will not run it for long... Its just a simple DC brushed motor.

Here is a video of my boat with 2 x 30lbs running at 4.5 knots (12v)... 24 hours non stop.

http://www.youtube.com/watch?v=34RkYTRzqsA

I also have made my own custom 6x9 inch props at one time..

If you do try the 24 volts, your current will go up also and you power will go up more than 2x.. Your speed will not double though
I think that is the best way to get 4 knots for 5min..

Eddie Weeks