Solar Powered Pontoon Boat

squarebob

A little history. I have been dabbling in solar for quite a few years. I have a solar powered door on the chicken coop that opens at dawn and closes 1 hour after dusk. It has been working for 6 years with one recent battery change. I have a 130w panel on a north south, east west tracker powering 4, 6v gc2 batteries in series hooked to a samlex 24v 2000w psw inverter , monitored by a bogart 2025. Backup power is a 6hp 4.4 kw single cylinder, 750 rpm diesel lister type engine that turns a 150amp, 24v truck alternator thru a balmar controller. It also spins a 7.5 KW gen head for other loads. Well I picked up an old (1995) 18' pontoon boat the other day with a 50 hp 2 cycle outboard. This boat was begging for a trolling motor. I picked up a 12v minn kota 30# trolling motor and rigged it up on the back of the boat to see what it would do. It would move the boat about 2 mph. I put on my inventors hat and went to work with a few ideas I had up my sleeve. I decided that I would use 2 trolling motors, one behind each log, to power the boat. I removed the top of the motors and rigged up some linear actuators for steering and also for power trim.

squarebob

I wired the motors in series so I could feed them with 24 volts. With the control heads removed, I ran the power to the motors thru a pwm motor controller rated at 1440 watts at 24v ( 60 amp). Motor amp checks revealed they required about 650 watts at 100% draw.

squarebob

I converted the folding bimini top to a framework for a solid top and a couple solar panels

squarebob

I have taken it out a few times just on batteries and with putting around and fishing I used about 35 amp hours in 4 hours. I have 4, 6v gc2 batteries mounted on the front of the pontoon

The atv winch makes for a great anchor windlass!!

squarebob

my days of hot rod boating are long gone

BB.

I would be careful with running two 12 volt trolling motors in series when connected to a 24 volt battery bank... The motors may not share loading equally.

Also, if (worst case) one motor tangles the prop in a net/rope/hits a sand bar/etc. and stalls, the current draw on that motor will dramatically increase and cause its voltage across the motor to drop. The other motor can see >>12 volts across it and overspeed/over current/or damage electronics (if present) in the motor.

Not saying it will happen (I don't know anything about your motors/etc.)--Just a concern.

-Bill "always looking for the downside" B.

Estragon

Interesting... I've been thinking of doing something similar if I can find a beater pontoon boat with good tubes and ok structure. I assume you're keeping the 50hp O/B and checking to be sure it starts regularly. You wouldn't want to count on the trolling motors to keep you off a lee shore in a squall.

littleharbor2

squarebob said:

my days of hot rod boating are long gone

Pretty sure nobodies going to confuse a pontoon boat powered by trolling motors with a hot rod boat. lol
 Had a customer buy some panels from me to build a personal sized pontoon boat which was powered purely from the solar panels, no batteries. He had a joystick setup to control power for steering. It turned out pretty cool. Of course the overhead solar array provided him shade as well.
 Fun idea, keep playing with it.

I don't suppose that's you in this picture.

NANOcontrol

I made a 1937 GarWood electric many years ago. Been wanting to build an electric launch with only a small battery and using a linear current booster to provide maximum power real time.

squarebob

NO, that wasn't me in the picture! I have completed the installation of 2, 360 watt, 72 cell panels on the roof. Wired them in series to a midnight solar KID controller with a Whiz Bang added to it.

jonr

I wonder if with independent power and forward/reverse, you could do away with the steering control.

squarebob

Estragon said:

Interesting... I've been thinking of doing something similar if I can find a beater pontoon boat with good tubes and ok structure. I assume you're keeping the 50hp O/B and checking to be sure it starts regularly. You wouldn't want to count on the trolling motors to keep you off a lee shore in a squall.

Need the O/B to get the bugger on and off the trailer. The ramp I normally use is very shallow and I have to get the car pretty far into the water and really "givver the beans" to unload and load.   

squarebob

jonr said:

I wonder if with independent power and forward/reverse, you could do away with the steering control.

That is a great idea. I have forward/reverse now. They are 12v motors and I have them in series to draw from the 24v battery bank. I wonder if I feed them independently with 24 volts but limit the amps if it would work out and not destroy the motors?

BB.

Many times, controlling the current to motors is actually better than controlling the voltage (assuming you do not over voltage at some point).

Using a switch mode buck power controller set for current mode should would work fine (need to control the controller...).

Of course depends on the motors (brushed, Permanent Magnet poly phase + own controller)...

Might be an interseting place to start (no nothing about website or products):

https://www.robotshop.com/en/brushed-motor-controllers.html

-Bill

squarebob

I am running the motors now thru a pwm controller so I was thinking I can dial back the controller to have the same wattage going to the motors on 24 volt as they draw on 12 volt. A motor on 12v  at WOT draws 28.5 amps or about 350 watts. If i feed ~ 350 watts at 24v the motors should be OK?  I could pick up another controller, one for each motor and be able to eliminate the steering by using motor speed and forward/reverse as suggested by jonr. Here is the controller I am using.

DC Motor Speed Governor (10V- 55V) 60A 3000W Forward/Reverse Switch Digital speed scale 0-100%