Run a trolling motor with a generator?

[mike64]

Thinking about picking up an inexpensive electric trolling motor this season. Not just for fishing, for backup too-- my outboard stranded me once last season (powerpack died) and I needed a tow.

I currently have a dual purpose battery-- it sounds like from reading other posts that boaters who have a trolling motor or other juice-sucking devices have a 2 battery setup-- cranking and deep cycle. I bet trolling motors will drain a battery fast.

Then I got an idea--I have a small 1200 watt 2-cycle generator we got free with a larger one we bought for home blackouts last year. It's the size of a small microwave. Let's say I want to take my boat out on a big lake where I'd really be SOL if the OB died. Could I bring the generator just for emergency and hook it up to the trolling motor? Could I run the trolling motor off the dual purpose battery otherwise just for light trolling? Or could I just run the troller off the generator all the time? Is this just a dumb idea all around?

 

[boat1010]

Re: Run a trolling motor with a generator?

Don't know that much about trolling motors but I'm guessing they are DC voltage and the generator will be putting out AC. If you have a battery charger you can charge the batteries with the generator.

 

[John_S]

Re: Run a trolling motor with a generator?

Trolling motors can get you back as long as the battery has enough reserve left. With a single battery, that usually leads to numerous attempts to start, before giving up, or the battery is to low to turn over engine. Also, at 3-4mph it can take a while to get back. Not desirable in emergency/bad weather conditions.

Unless your outboard can easily be started in manual mode, I would not try to use a single battery.

AC 110V generator? Generator power inverter or charger, and then the trolling motor. I would lean to your last question being "yes".

 

[Silvertip]

Re: Run a trolling motor with a generator?

Most generators have a 12 volt battery charging output on them. the charge rate however is probably in the 10 amp range. Most 12 volt trolling motors draw in the range 40 - 56 amps on the fastest setting so a 10 amp 12 volt output would definitely not work. If you attempted to use a 110 outlet to power a 110/12 volt inverter, you would need a very expensive and very large inverter that can also handle 40 - 56 amps so that too becomes an bad choice. Trolling motors are intended to be run from a deep cycle battery and the largest capacity you have room for. It sounds to me like you are thinking about a troller for emergencies more than fishing. If that's the case, you need a small gas kicker (5 - 7.5 - 9.9). If you have room for a generator you have room for a second battery. The obvious solution is to get the engine professionally tuned so it is reliable.

 

[boat1010]

Re: Run a trolling motor with a generator?

Most generators have a 12 volt battery charging output on them. the charge rate however is probably in the 10 amp range. Most 12 volt trolling motors draw in the range 40 - 56 amps on the fastest setting so a 10 amp 12 volt output would definitely not work. If you attempted to use a 110 outlet to power a 110/12 volt inverter, you would need a very expensive and very large inverter that can also handle 40 - 56 amps so that too becomes an bad choice. Trolling motors are intended to be run from a deep cycle battery and the largest capacity you have room for. It sounds to me like you are thinking about a troller for emergencies more than fishing. If that's the case, you need a small gas kicker (5 - 7.5 - 9.9). If you have room for a generator you have room for a second battery. The obvious solution is to get the engine professionally tuned so it is reliable.

As always Silvertip you have some very good advice.

 

[mike64]

Re: Run a trolling motor with a generator?

That IS great info Silvertip, exactly what I was looking for. I figured it was a crazy idea, I just wasn't sure WHY. Now i know

I had figured it wouldn't be that difficult to convert to DC power, but I didn't consider amperage.

...It sounds to me like you are thinking about a troller for emergencies more than fishing. ]If that's the case, you need a small gas kicker (5 - 7.5 - 9.9). If you have room for a generator you have room for a second battery...

...The obvious solution is to get the engine professionally tuned so it is reliable.

Great points. I plan to get my outboard in as good shape as I can get it. But it's 37 years old, and some type of backup would give a little peace of mind. a gas kicker WOULD be the best way to go, but that's not going to happen this season.

My thinking was more along the lines of, I'm broke this year and I have a free small generator I'm not using. How can I make this work for me? Maybe I'll just use it for watching tv and making blender drinks out on the water

 

[Chris1956]

Re: Run a trolling motor with a generator?

Mike, If your generator has a 12VDC tap, you could run the generator to charge the battery which runs the trolling motor. The battery would last a lot longer, and you could probably find a setting that allowed you to continue to motor on the battery until you ran out of 2 cycle fuel.

Alternatively, since your generator puts out 1200 watts, and I assume that is at 110VAC, that can be converted to about 100 Amps at 12VDC. The simplest thing is to wire in a large battery charger (50+ Amps) and charge the battery, as you use it.

 

[Silvertip]

Re: Run a trolling motor with a generator?

There is no "free lunch" here guys! The generator, if has a 12 volt charging output, can certainly be used to charge the battery while operating the troller. But the troller is using more current than the generator is putting back into the battery (about 10 amps in but 40 - 50 amps out). Yes, you can have more time on the water than without it but it is still a losing proposition. As for the 115 feeding a battery charger, why bother if the generator already has a charge output. It eliminates the expense of the charger. But if that's your choice, I suggest you price a 30 or 40 amp smart charger. Again, you can certainly use a cheaper battery charger but then you run the risk of improper charging of the deep cycle battery and it becomes toast. The man is on a definite budget so addiing anything other than the free generator is apparently an issue. Lastly, I don't know how quiet the generator is, but on a small boat the constant "din" of the generator would drive me nuts in short order, especially if I was trying to fish.

 

[Wee Hooker]

Re: Run a trolling motor with a generator?

As a coincidence, I've been shopping for a 1000-1600W generator to charge my trolling batteries while on extended fishing/camping trips. I can tell you that most out there in this range only put out 8.3A peak and 7A continuous DC.
Even the bigger 3000-4500W units barely double this. No way your going to run a TM off one of these as they are barely acceptable for charging. As Silvertip said, no free lunch in energy. Adding an inverter to the AC side would just increase the inefficiency due to heat loss.

As mentioned , you want a small gas kicker. Even a 3.5-5 hp 2 stroke is lighter than a 80-100# electric TM ( or the generator) and delivers more thrust without fear of battery drain..

 

[Shizzy]

Re: Run a trolling motor with a generator?

how large of a lake are we talking? you should have easily a few hours of time on the battery when running the trolling motor if you keep it off the highest setting.

 

[mike64]

Re: Run a trolling motor with a generator?

There is no "free lunch" here guys!

Now I guess you're going to tell me my plans for building a perpetual motion machine aren't going to work either

I'd say Silvertip and Wee Hooker have answered this one pretty definitively. If I do get a trolling motor, I'll just get a deep cycle battery to run it. Maybe a gas kicker next year.

Thanks again guys.

 

[John_S]

Re: Run a trolling motor with a generator?

Sell the "free" generator, which sounds like it isn't being used. That along with what you were planning to spend for a battery and trolling motor should get you into a good used kicker. You will only be limited by how much gas you carry. A fully charged Deep-cycle will probably last around 3 hours, and give you a possible range of 12 miles. If you are on the Great Lakes, that might not be enough.

 

[mike64]

Re: Run a trolling motor with a generator?

Sell the "free" generator, which sounds like it isn't being used. That along with what you were planning to spend for a battery and trolling motor should get you into a good used kicker. You will only be limited by how much gas you carry. A fully charged Deep-cycle will probably last around 3 hours, and give you a possible range of 12 miles. If you are on the Great Lakes, that might not be enough.

That's a good idea-- I considered that, but there's probably going to be a time & place where I need to run a power tool or something and there's no electricity. In fact, if I did sell the generator, that situation would probably come up a week or two later. funny how things work out that way.

 

[John_S]

Re: Run a trolling motor with a generator?

Yea, I understand murphy. He has been hanging around my entire life. I bought a decent generator a few years ago after being out of power for a week. Only have had minor outages since. I imagine that means that the "big" generator is not portable.

Of course, also according to murphy, that if you have a battery that will last three hours, you will break-down 4 hours away.

 

[mike64]

Re: Run a trolling motor with a generator?

Yeah, funny how Murphy's Law works both ways-- if you prepare for something to go wrong, then it never seems to happen.

the 5000 watt generator we bought last year for the frequent power outages we get in our neighborhood-- never had to use it until a car took out a power pole across the street last Saturday. Got out the generator, added the oil, read the startup directions, got it running, switched to the secondary breaker panel...only had a gallon of gas so I drove out and got 10 more gallons. By the time I got back the power was back on (they backfed it somehow). I was almost disappointed that we didn't have a good 3 day outage

 

[Silvertip]

Re: Run a trolling motor with a generator?

You are looking at Murphy in entirely the wrong way. You had a power outage so you obtained a generator and haven't had a serious outage since. Look at the generator as a power outage insurance policy. You have crash insurance on your vehicles but you don't expect frequent crashes do you? If you did not carry insurance Murphy would step in and you would certainly have a crash 15 minutes after the policy expired. See how logical it all becomes. I built a generator some years ago under the same "storm related" circumstances. It has never been used to provide emergency power but I fire it up periodically and power my large garage shop vac to give the rig a little exercise.

 

[mike64]

Re: Run a trolling motor with a generator?

Don't get me wrong, I wasn't complaining. I was imagining Murphy's Law as having a "dark" side and a "bright" side, if you will. Yin and yang. It is just a made-up law, after all, we ain't talking physics here. By the same token, if I did buy a gas kicker and it "caused" my main OB to never break down, that would be OK with me.

 

[Silvertip]

Re: Run a trolling motor with a generator?

And I wasn't taking issue. Merely addiing a little twist to a conversation. There must be something in the water because people seem to be way overly sensitive as of late. That's twice today.

 

[mike64]

Re: Run a trolling motor with a generator?

And I wasn't taking issue. Merely addiing a little twist to a conversation. There must be something in the water because people seem to be way overly sensitive as of late. That's twice today.

Silvertip, I wasn't taking issue, I thought I was joking around with ya. I didn't take your post badly at all-sorry about the misunderstanding. Guess I needed to add a couple of these in my last post--

Anyway, you might know your watts and amperages, but you completely misunderstand the intricacies of Murphy's Law.

 

[John_S]

Re: Run a trolling motor with a generator?

I would think a 5K generator would still be rather portable. While not as easy or convienent for very small power requirements, enough so such that if you really needed it, it could be done. Mine is a little larger, 6.6K (8K surge) 13hp. I have a wheel kit for moving it about, but takes two to lift into the back of the suv or trailer. Works fine for running numerous power tools at remote locations. Just one last attempt to get you to go for the kicker!