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Old 19-06-2017, 21:23   #46
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Re: Small generator + electric propulsion for dingy



Here's a good solution.
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Old 07-07-2017, 08:29   #47
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Re: Small generator + electric propulsion for dingy

Help please: I started working on my project, fiberglass dinghy with trolling motor powered by weed eater generator.

I have a trolling motor Minn Kota turbo 555, bought not complete, no speed control unit.

The motor as 2 large wires red and black and 4 small wires, white, blue, yellow, green.

I can't find any info online about the speed control for this unit, these wire colors or number of wires. Does anybody know how the speed control works on a Minn Kota, or have any other info that might help understand what I've got?.

The motor runs when you hook up the red and black, the other wires are not hooked up to anything. I tired shorting the other wires together in all patterns and they make no difference and no sparks.

The motor draws 3.65 amps at 12 volts spinning in air, not tested in water yet.
The case mentions 5 speeds and 33 pounds of thrust but online info about 5 speed controls have different numbers of wires and different colors. I can't find any info about turbo 555.

I want to know how this thing is supposed to work, I was surprised when the motor turned with nothing but + an - hooked up to a 12 volt battery, I expected something else would be needed to decide what speed to run. I was also surprised I couldn't find anything online about this model.
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Old 07-07-2017, 09:51   #48
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Re: Small generator + electric propulsion for dingy

Okay, heres your solution.

36v trolling motor.

Cheap Chinese PWM controller that can accept 48v input and handle 1kw or more.

48v 20ah lithium ebike battery.

voltmeter and ammeter to measure power going into the motor.

The 36v trolling motor can be overvolted slightly if total power is at or less than the rated power in watts. Watts is volts x amps in this case. The PWM controller is an efficient way of controlling power into the motor. Most cheap trolling motors do not have PWM control built in and are VERY INEFFICIENT, except when ran wide open. So you run the motor with the throttle wide open, but regulate the input with the PWM controller. Cheap PWM controllers is something that the Chinese are very good at. The 48v ebike battery is not cheap. But it is very energy dense. Light, portable, and has a built in BMS. Plus you can use it to power an ebike if you ever get or build one. I have even used it to power my boat, for short distances at low power, jst to see if I could do it. Anyway the battery carries easily in a small backpack along with the controller. Sling the trolling motor over your shoulder and you are portable.

12v is not very efficient. Just sayin. But if you are only concerned with cost, go with a 12v motor and a decent sized 12v battery or two 6v batteries. At one extreme, you could get two GC2 golf cart batteries from sams club for $85/ea and motor at 5a for about 25 hours without recharging and still not be below 50% charge. For the very cheapest sort of trolling motor again you need an external PWM controller for reasonably efficient operation. A smaller 12v battery would probably be sufficient, though. A 100w solar panel as a range extender would help a lot, and it would eventually charge your battery with the right charge controller. Plus it would provide shade for the operator.

Cheap generators or cheap engines is something that the Chinese do in great volume but with extremely low quality and durability. They don't last. They generally can't be rebuilt. STAY AWAY from any Chinese build infernal combustion engines. And what everybody else said about using an engine to turn a generator to make electricity to power a motor to turn a prop, vs simply using an engine to turn a prop, is nothing but the pure unvarnished truth. There are applications where diesel/electric or even gasoline/electric I guess, makes sense. Usually only when operation at very low power levels for long periods of time are needed, or instant constantly variable power control, stuff like that. Transmission elimination. Well, that doesn't apply to pushing a dink. Don't go there. If you want to burn liquid petroleum products to push your dink, get a small outboard. If you want clean and quiet, go electric, maybe with some solar added.

Sailing/rowing the dink is old school but it works.
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Old 07-07-2017, 09:57   #49
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Re: Small generator + electric propulsion for dingy

Quote:
Originally Posted by mitiempo View Post


Here's a good solution.
I think you have nailed it.
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Old 07-07-2017, 12:11   #50
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Re: Small generator + electric propulsion for dingy

The idea of using a small generator to power an electric motor that powers the dinghy has the advantage of having a generator that can do many things, it can power the dinghy, can power an electric bike, can provide power at a beach cook put, or it can charge batteries if needed. It's much easier to keep an electric propulsion system operating. It can set for years with no maintenance and immediately start right up when it is hooked to a voltage supply.
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Old 07-07-2017, 13:52   #51
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Re: Small generator + electric propulsion for dingy

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Originally Posted by mitiempo View Post




Here's a good solution.


Looks nice. You'll also see a flexible panel bolted onto the middle seat of a Walker Bay to a deep cycle battery to a trolling motor.

Yeah bit of a shadow on the panel with crew sitting on it but recharging kicks in once you hit the dinghy dock.
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Old 07-07-2017, 14:07   #52
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Re: Small generator + electric propulsion for dingy

---Quote
I don't like to be one of those people who heap negativity on other people's plans, so
I'll bite my tongue.

The loss of efficiency of this setup compared to a normal outboard is probably not a big
deal.

Don't neglect comments above, however, about the challenges of keeping seawater splashes
off a running generator carried in a dinghy -- just a little seawater will kill one of
those things very quickly. Running the exhaust in a way to keep it from killing people
on board with CO is another significant challenge, especially since you can't have
something really hot -- like an exhaust pipe -- in contact with inflatable tubes.
Keeping the other hot parts of the generator away from the tubes (and floor if the dinghy
is not a RIB) is another challenge .

If you can overcome these things, we will be impressed -- let us know. If you can't --
the good news is that it will be easy to swap out the generator for a battery, or the
whole setup for a small, light, cheap outboard. It's great you're doing it -- now we'll
know for sure whether it works, instead of just speculating about it. Just be careful
with the CO.
***************
I'll be using this in a 2 piece nesting, and sailing fiberglass dinghy, Weed eater hot exhaust is shielded extremely well, I don't think the CO2 in the exhaust is any problem to worry about because you will be moving and unless you are moving with a tail wind of exactly the same velocity you will not be in the exhaust. I'm not building this for everyday use, it's for the one time that you have to travel 50 miles in the dinghy for some reason. If I need to cross a wind swept bay with the possibility of splashes coming over the rails I'll just install the mast and sail and have some excitement. I normally row, I rowed the dinghy 9 miles earlier this week to see the fireworks, and I just got out of my 2 mile afternoon row for exercise. As for a splash stopping it, I would expect most of this will be happening in rather sheltered waters, such as up the river to the next big town kind of thing. The trolling motor will store away in a small space, basically it will be a transom clamp, a 12 inch stem with a T tube on top to accept a steering rod and the motor unit with prop at the bottom. I just need to learn how the speed control used to work so I know how to design something to make it work for me. I expect I might use the weed eater generator on an electric powered bike for a similar use, for that once a year 250 mile trip on the road to get a part in the next big city, instead of the normal 5-20 mile bike trip from anchorage to town to resupply the food bins or have a beer. Flexibility and lots of options is what it is all about,
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Old 07-07-2017, 14:10   #53
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Re: Small generator + electric propulsion for dingy

One hp = 745 watts, more or less. So maybe your 2.5hp engine really needs 2hp most of the time, that leaves you 1/2hp for the alternator. Which might be 50% efficient. Which might leave you a whole 1/4 hp for electricity. That's 1/4 of 745 watts, 186.25 watts, and you'll want 14.4 volts, which leaves you a whole 12.9 amps. With the motor running at full speed, because alternators put out next to nothing at idle.

Not a real big benefit to doing it that way, is it?
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Old 07-07-2017, 14:31   #54
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Re: Small generator + electric propulsion for dingy

Quote:
Originally Posted by jheldatksuedu View Post
---Quote
I don't like to be one of those people who heap negativity on other people's plans, so
I'll bite my tongue.

The loss of efficiency of this setup compared to a normal outboard is probably not a big
deal.

Don't neglect comments above, however, about the challenges of keeping seawater splashes
off a running generator carried in a dinghy -- just a little seawater will kill one of
those things very quickly. Running the exhaust in a way to keep it from killing people
on board with CO is another significant challenge, especially since you can't have
something really hot -- like an exhaust pipe -- in contact with inflatable tubes.
Keeping the other hot parts of the generator away from the tubes (and floor if the dinghy
is not a RIB) is another challenge .

If you can overcome these things, we will be impressed -- let us know. If you can't --
the good news is that it will be easy to swap out the generator for a battery, or the
whole setup for a small, light, cheap outboard. It's great you're doing it -- now we'll
know for sure whether it works, instead of just speculating about it. Just be careful
with the CO.
***************
I'll be using this in a 2 piece nesting, and sailing fiberglass dinghy, Weed eater hot exhaust is shielded extremely well, I don't think the CO2 in the exhaust is any problem to worry about because you will be moving and unless you are moving with a tail wind of exactly the same velocity you will not be in the exhaust. I'm not building this for everyday use, it's for the one time that you have to travel 50 miles in the dinghy for some reason. If I need to cross a wind swept bay with the possibility of splashes coming over the rails I'll just install the mast and sail and have some excitement. I normally row, I rowed the dinghy 9 miles earlier this week to see the fireworks, and I just got out of my 2 mile afternoon row for exercise. As for a splash stopping it, I would expect most of this will be happening in rather sheltered waters, such as up the river to the next big town kind of thing. The trolling motor will store away in a small space, basically it will be a transom clamp, a 12 inch stem with a T tube on top to accept a steering rod and the motor unit with prop at the bottom. I just need to learn how the speed control used to work so I know how to design something to make it work for me. I expect I might use the weed eater generator on an electric powered bike for a similar use, for that once a year 250 mile trip on the road to get a part in the next big city, instead of the normal 5-20 mile bike trip from anchorage to town to resupply the food bins or have a beer. Flexibility and lots of options is what it is all about,
OK, good luck! Hope you prove us wrong. If not, it will be fairly simple to substitute a battery.
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Old 14-07-2017, 04:58   #55
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Re: Small generator + electric propulsion for dingy



Problem solved.
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Old 14-07-2017, 07:51   #56
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Re: Small generator + electric propulsion for dingy

I've tested my trolling motor and have it figured out, it's an older Minn Kota, it has 5 speeds and each speed is a separate wire, I ohmed out a speed switch from a newer Minn Kota and I think they use combinations of 2 or 3 wires positive to get the different speeds. I got a transom mount for the motor today, it's time to start the weedeater generator and see what it does. I had to test the motor in water attached to the dock to learn how the speeds work on it, testing amps with the motor spinning in air showed no difference between all the different wire combinations. In water with the amp
meter is was immediately obvious what was what. Supposed to be 33 lb thrust, it drew 14.4 amps max sitting still on a car battery at 12.2 volts no load.
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Old 14-07-2017, 08:23   #57
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Re: Small generator + electric propulsion for dingy

Quote:
Originally Posted by jheldatksuedu View Post
I've tested my trolling motor and have it figured out, it's an older Minn Kota, it has 5 speeds and each speed is a separate wire, I ohmed out a speed switch from a newer Minn Kota and I think they use combinations of 2 or 3 wires positive to get the different speeds. I got a transom mount for the motor today, it's time to start the weedeater generator and see what it does. I had to test the motor in water attached to the dock to learn how the speeds work on it, testing amps with the motor spinning in air showed no difference between all the different wire combinations. In water with the amp
meter is was immediately obvious what was what. Supposed to be 33 lb thrust, it drew 14.4 amps max sitting still on a car battery at 12.2 volts no load.
That type motor control is only efficient at full power. If you need a reduced power level for long periods of time, I definitely suggest using a separate PWM controller. You were running the motor at 54 watts, by the way. A 1kw rated Chinese PWM controller will be quite enough for this and they are cheap on fleabay.
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Old 14-07-2017, 12:24   #58
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Re: Small generator + electric propulsion for dingy

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Originally Posted by GrowleyMonster View Post
That type motor control is only efficient at full power. If you need a reduced power level for long periods of time, I definitely suggest using a separate PWM controller. You were running the motor at 54 watts, by the way. A 1kw rated Chinese PWM controller will be quite enough for this and they are cheap on fleabay.
I never really intend to use this, it is only for emergency, if I need to travel 50 miles in the dinghy. I don't ever expect to need reduced power, or any power actually, so I really could care less about efficiency. Thanks for the input.
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Old 14-07-2017, 20:35   #59
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Re: Small generator + electric propulsion for dingy

My Minn Kota Riptide 55 lb thrust motor with the Maximizer continuous throttle uses just above 50 amps at full power and about 1 amp at trolling speed. Measured with an accurate clamp meter.
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