Sooo... I had a kayak for a while.  Didn't much enjoy the paddling part of it, was too much work for something I thought should be relaxing.  

Now, there are plenty of motorized kayaks out there using deep cycle batteries and trolling motors.  Of course, this is all fine and good however the thought of sole propulsion via battery alone just plain turned me off - Battery wears down over time, takes time to charge/recharge so no spur of the moment trips unless you keep it on a maintainer, trolling motor performance sucks below 50% charge, etc.

A friend of mine uses this setup in a pond prowler and he related a story where he ran out of juice in the middle of a lake.  I (jokingly) told him that he should get one of the $80 harbor freight generators so he could recharge the battery AND skirt the electric motor only rules.  From there this degraded into a whimsical brainstorm of how to get the biggest boat on one of those "electric only" lakes with talks of three phase motors and diesel generators.

However once I started thinking about it - why not put one of those harbor freight generators in a kayak?  Of course it would have to have modifications to the air and exhaust system, but I'm sure it could work.

But my question is, not knowing a lot about electricity - is this even possible?  Say the trolling motor draws 25 amps and you have a 100 AH deep cycle battery.  This would give you 3 hours of run time.
Now you need the generator to replinish the battery at this rate - and use an inverter since the cheapo generator has 120V AC output only.  

So my question to those that know more about this than I do... Is this remotely possible?  YES, I UNDERSTAND THIS IS A DUMB FUCKING IDEA.  However, I am a sucker for projects like this and I enjoy a challenge.  

Here's a conceptual drawing.  Of course there would need to be additional systems, like a blower, a way to route the exhaust, etc.



I'm seeing a LOT of generators out there with a 12 volt output with a MAX of 8.3 amps DC.  Is there such a generator that has more available amperage, say... 30 A DC????

You would still have a gas motor out on the lake.

No, he'd have a gas engine out on the lake. The motor would still be electric.

That was a joke that Inspired my idea.

I'm not trying to skirt the rules, because I'd be on a river.  Pure electric systems aren't that great on the river due to the tidal currents - a tide change could put you beyond your range of getting back.

Damn, is my idea THAT stupid?

All I need to know is if a battery can be discharged @ 25 amps and recharged at the same rate....

Yes. Think about it, you'd basically be running the small trolling motor with the generator. Depending on the size of the generator and the size of the trolling motors you could run multiple trolling motors with it if you wanted.

Would this cause any damage to the battery, or have any other concerns about over charging the battery (IOW the generator output is greater than the demand) so would I need a voltage regulator or charger or something?

Why bother with the battery?

Just run the electric motor off of the generator, worse case scenario you would have to use an inverter - http://www.ehow.com/how_8024099_vary-speed-ac-electric-motor.html -  as an intermediary.


The Honda EU2000iA (and the 'Camo' version) provides 8A 12vdc output - I assume of course the electric motor runs off of 12vdc but this should take care of it.

I'd like to use the generator during "cruise" so to speak.  Once I got to a spot I wanted to fish/explore I'd want to use the battery to run the lights, fish finder, and maneuver around quietly.

What you've described is basically a gas/electric hybrid kayak.  Verily, the Prius of kayaks.

I don't think you're going to like sitting next to the $80 generator.

Yes, you'll need a voltage regulator of some type. What you'll need will be dependent upon the size of batter and draw for the trolling motor(s). If you overcharge a battery and it should fail in the best case scenario you'll just kill the battery, in worst case you'll boil the acid and cause a hydrogen build up and it can explode.

Instead of the generator, just bring an extra battery with a cross switch. You can charge them one at a time on land, then use them one at a time.

This is what I would do. You could bring multiple batteries and it would be a lot easier and make for a more pleasant boat ride than sitting next to a cheap generator the whole time.

i'm sorry, what was the question?

What about a hydro generator thing? Use the current from the boat moving to charge the battery?

Genius!!!!!!! Or how about since you generally are only going to be on the lake on sunny days, why not one of the roll-out solar panels.








 

Add a windmill and we might be on to something here.

Damn right.  The more I think about this, the dumber I think it is.  It also makes it more of a challenge.

In fact, I think your buddy is on to something.  The HF generator has 120V AC output only, turning that into usable 12 volts is going to be difficult.  The rigged up alternator is looking more and more attractive by the minute, but adds additional complexity.

Of course this is all just brainstorming until I can find a cheap enough kayak that I'm willing to hack up for this project.  Someone mentioned the Honda generator.. yeah, i'm not putting no $1,000 generator in this failboat...

Interesting idea.  But I'd use a Honda generator.  A Harbor Freight generator is obscenely loud.
 

And a honda generator is obscenely expensive to be in such a cobbled together contraption

I believe modern locomotives use this system.

Modern SHIPS with azipods use this system as well.

Bump for generator question.

That's going to be one heavy kayak.

I would get a bigger boat.

Extension cord

Ones I'm looking at have a 350 Lb capacity.  About 200 for me +gear, 50lbs for deep cycle battery, 20 lbs for trolling motor and another 30 lbs for whatever generator I choose gives me 50 lbs to spare.

If I could find a 14' that would be even better as they typically have a 450 lb capacity, but would be a bit unwieldy trying to transport in my 8' bed.

Pretty sure you need a clean sine wave generator to properly power the inverter....need a Honda Inverter Generator like the EU1000is or equivalent



 

so just say the trolling moter uses 12 volts and the generator puts out 120 volts

Do the math get 10 trolling moters and run direct from the generator  

Man you could pull skiers with that thing