Engine Hacks: Electric Drill Made Into A Trolling Motor

We knew our engine hacks theme would come down to an argument over the difference between “a motor” and “an engine” so after much deliberation, name calling, restraining orders, and a duel we’re happy to put up [Berto]’s DIY trolling motor made out of an electric drill. The project is probably inspired by [Berto]’s collapsible amphibious e-scooter that used the same electric drill propulsion setup.

The build is just a few pieces of wood, drill rod, some hardware and a prop. Definitely not the most complicated build. This isn’t the speediest motor ever when attached to a canoe, and isn’t meant to be a primary means of propulsion. That’s not a problem for this build – trolling motors aren’t designed to be fast or powerful. There’s no word on how much thrust [Berto]’s motor can put out, but it is a nice bit of MacGyverism to build a boat motor out of spare parts.

Check out the build walk though video after the break to see the motor in action.


48 thoughts on “Engine Hacks: Electric Drill Made Into A Trolling Motor

  1. Trololololol

    But seriously, this is interesting but not something I would have ever thought of to use a battery powered drill for. I give the guy props for ingenuity! Would be interesting to see what he gets on a single charge.

    1. The internet has ruined me; this is the same thing I thought as well, except I was trying to figure out how you’d troll with an electric drill (other than mounting it near a CRT and turning it on).

  2. I tried using a cordless drill on both a bike and as a steering servo retrofit to a kid’s electric ride on car. These motors have ample torque for these purposes. The downside is that the drill chuck constantly undoes itself. There is no way to make them stop from wobbling themself loose no matter how tight you attach them. The only solution i found was to weld chuck permanently to the drive shaft. On the plus side, you can afford to permanently devote a cordless drill to these types of purposes cause they are so cheap.

    1. The downside being, that because they are so cheap they’re not designed to be run continuously.

      So you have to replace the whole drill a few hours in use after you permanently welded it to the shaft.

    2. Ah yes, that’s why you should never use a Jacobs style chuck in a milling operation. It doesn’t matter how much you tighten it, it will come undone.
      Rather than welding it in place, you could have drilled across the shaft and through the side of the chuck to accept a pin. That would have allowed for some motion of the shaft but still kept them rotating together and been removable.

      I don’t know how the original project keeps the prop on the end, it’s another drill chuck which looks to me like it should unwind.

    1. I once calculated how much it would take to power a proper outboard electric motor, and it was a bit too cumbersome.

      It takes about 200 W to run the motor, so for 8 hours you need 140-150 Ah of batteries. That in itself isn’t really a problem, it’s just a bit heavy.

      But the solar panels are. You get about 100 W per square meter when the panel is aimed at the sun. If it’s fixed to the midday sun, your daily coefficient of power is approximately 10%. That means you get 24h x 100 W/sq-m x 10% every day.

      That means for every 3 by 3 feet solar panel, you can only collect about one hour (200Wh) of driving each day. You need eight panels to recharge the entire battery in a day, but that would be impossible to carry along in your boat.

      You simply can’t take a small boat, possibly a canoe, and put a rack of 8 sq-m of paneling on it, with pivots to aim it properly. It would look like a sailboat with sails made out of solar panels.

      1. I just made a motor setup for my Kayak, It uses a 12/24 volt at 2 amps sewing machine motor and is more than powerful enough at 1/4 power 8,000 rpm max. I just need to install a speed controller and wait for the lake to thaw, It only takes about 4 lbs of thrust to move a kayak with a 150 lb person a real trolling motor is rated for about a 1 ton boat…

        1. Aaron, do you happen to have any photos or more details on your setup using the sewing machine setup? That sounds like a fantastic idea and would love more details about it.

    2. It is very surprising how little solar panels actually produce. For example, the photovoltaics in Germany, installed under government subsidies, are only producing around 7% of their nominal on average.

      That’s because half of the day is actually night, and on the other half the panels are aimed somewhere else than the sun, except for couple hours in the middle, and then it might be cloudy.

      1. I’ve seen pictures of one of those solar plants in Germany. The panels were mounted too low to the ground to mow under them (should have put down weed barrier and gravel), the weeds were growing high and shading the panels and they were mounted at a fixed angle instead of on sun tracking mounts.

        The company ripped off the government big time then abandoned the facility.

      2. It needs something like a plastic cup on the front side of the prop, fitted around the drill chuck, to streamline the prop hub a bit.

        There’s a lot of power being lost to the drag on the prop hub’s cup shape.

        Alternate option, a flat disk placed over the hollow front of the prop hub would reduce the drag.

  3. You could always get a small generator and use it only for extending range…it would still qualify as an electric vehicle by the standards of every manufacturer out there…and if it is just a small fishing boat, you can charge it up at home from some nice, earth-friendly, coal burning power plant from 50 years ago with no emission controls.

    1. Been there, done that. :)

      Hooked up a 1 HP gasoline powered water pump engine to a car alternator. Instant hybrid boat. It was notoriously inefficient though – and the engine was too noisy.

  4. Very clever idea, but I wonder how long the drill would be able to stand up to the abuse that it would receive, plus the high duty-cycle (e.g. on for very long periods) operation.

    (to add my two cents to the motor vs engine debate, if it isn’t converting potential energy from the flow of heat into kinetic energy, it isn’t an engine)

  5. How about just using a cheapo 12V bilge pump (sparkfun sell one) which is putpose designed for shifting water. Mount it on the hull of the canoe with some rubber suckers and off you go.

    Or there’s always the 70,000BC invention called the “oar”.

  6. Neat build and a neat idea that inspires other ideas. In fact, given that Hackaday has posted hacks based on themes before, I think a series of rechargeable drill motor hacks would be awesome. But…

    If I see one more wanker arbitrarily attach the word “green” to a project, I think blood is going to start spraying out of my eyes and ears.

    What is green about a cheap electric drill (manufactured in a 3rd world country with no regard for worker safety, proper disposal of chemicals, or factory emission controls), a tiny rechargeable battery pack (that is not only inefficient, but full of toxic chemicals,) and a plank of pressure-treated wood (saturated in more toxic chemicals.) Let’s not forget all of the oil-sourced plastic implicit here… And then what…? After after an hour or two of accumulated use the intermittent-duty motor and gear train self-destruct and the whole enchilada ends up in the trash. Seriously… this is “green”?

    Back in the 50’s, marketing types decided that “atomic” was a word that people associated with high power and futuristic design. For a while, everything from toys to laundry detergent to chewing gum had the word “atomic” associated with its promotion or advertising. This imagery was directed at easily manipulated people with disposable income.

    Nowadays, the sucker word is “green.” “Green” is a word that allows certain people to absolve themselves of their guilt over being alive. “Green” projects, products, and policies enable these people to sleep soundly at night, deluding themselves into thinking that they’ve “saved the earth,” while what they’re actually doing is dumber and more eco-destructive than what they were doing before.

    Again, I have no issue with this project. I like it, and I want to see more like it. It’s just the arbitrary and superfluous use of the cursed G-word that raises my hackles.

    1. No kidding. You want a “green” way to power a boat? How about a sail, or some oars? Either way you have something that can be made out of goods available anywhere (cloth, wood) and will never run out of power.

      1. @N0LKK
        Sir or madam, I don’t know what kind of fishing one does with such a small motor-engine. In lake fishing it’d scare the fish off, out on the sea you’re not going to pull in a marlin with anything running a trolling motor.
        If you’re running this motor/engine, you’re not fishing at all but on your way to it.
        Fishing trawlers I know of but fishing trollers not.
        Get out there early in a canoe with a can of corn and a net (game wardens frown on this practice.)

  7. Wow! I must have missed the mention of “green” in the video, or on Barthos’ web page. Grinding flat for the chucks to grab on might help them not to loos their grip in prolong operation. Assuming a reversible drill, and a right angle adapter designed to be used with reversible drills the chucks are are appropriate for such use. Engine Vs. motor the only time I enter that debate, is when I realize doing so can really wind someone up that is really fervent about it.

  8. I’d agree that drill motors and gearsets aren’t meant for continuous use, but any reasonably decent drill will have a lubricated all-metal gearset, that is designed to take some impacts when a drill ceases, and the full motor torque when the drill bit is stuck, both of which don’t happen in this application, so it will probably hold up for quite a while, if you keep it properly lubricated.

    The motor will get hot, but that could be fixed with a few extra vent holes and a fan for a little additional airflow. If the current is regulated, it will take some extra voltage for higher speed without wearing out to quickly.

    The bearings in the motor, which usually are slide bearings instead of ball bearings, and the brushes are probably the parts that will wear out first.

    Drills are cheap to come by second-hand, because the battery is usually the first part to fail. The stock batteries are far to small for this purpose anyway, and there is no requirement to use a compact, original battery when using the drill in this way.

    Just make sure the whole thing stays dry and clean, as water and dirt will destroy it very quickly.

    I guess the point isn’t to design the best, most efficient, and reliable drivetrain you can, but to use the parts you have available to build something reasonable.

  9. @karl You do realise that Top Gear is a British show, of which they made a fairly flaccid American (and a truly woeful Australian) version. Saying “the British Version of Top Gear” is like saying “the American Version of Coca Cola”.

  10. Ok, maybe on the end of this line of ‘overwhelming’ and ‘serious’ comments, a ‘late’ comment of the maker of the project.

    SparkyGSX – Drills are cheap to come by second-hand, because the battery is usually the first part to fail. The stock batteries are far to small for this purpose anyway, and there is no requirement to use a compact, original battery when using the drill in this way.

    What to do with all this 1.000.000 cordless drills with NiCad. battery’s laying around for years in the makers shed?
    Take the cells out of the battery box and bring it to the intake station. Make in the battery box a socked for plugging an external 12V gel/lead battery. That’s what I did; recycling and re-use of a mostly unused cordless drill because of the battery.
    Recycling is ‘eco’ as is re-using! The wood I chooses was impregnated with wax without any ‘toxic chemicals’. The wood is sustainable, because they plant a new tree for the one they cut. You can call this a ‘eco method’. @PI – I just change the name to ECO and you feel already better, is’t it? When you don’t have a

    A cheap electric drill (manufactured in a 3rd world country with no regard for worker safety, proper disposal of chemicals, or factory emission controls), a tiny rechargeable battery pack (that is not only inefficient, but full of toxic chemicals,) then you are a non-hypocrite. The point is; Can I repair, re-use, recycle the existing stuff ? Many comments about the lifespan of the drill. Don’t worry, let it be a one- or two year use before ‘destruction’; we have a lot of fun with the canoe and the re-used cordless drill on the waters. It’s a fun project.

  11. At the moment I’m trying to make a motor for my Kayak, sick of getting cramps and being stuck on the lake…I purposely bought a 6000 rpm high torque dc motor rated at 12 volts 5 amps max, I have a 7 amp hour battery and a 12″ by 12″ high efficiency solar panel rated 15 volts at 4 amps, I should only need about 1500 Rpms and have voltage regulators….Let me know what you think, I’ll at least have power at camp…my Kayak should only need 4-5 lbs thrust…

    1. Just some thoughts…

      First, solar panel manufacturers are ludicrously optimistic when specifying power. When they say 60 Watts, they mean on the planet Mercury, on the equator, for 5 minutes either side of noon. You typically get around a tenth, rule of thumb, of what you’re promised in a non-optimal setup. In an optimal setup, see “noon, Mercury”, etc.

      If you don’t have a gearbox, you should probably have bought a motor that had the right torque / speed specifications. Sure you can reduce speed with a motor controller (not a voltage regulator, that’s different) but you’re losing most of the power capacity of the motor.

      12V at 5A is 60 Watts. 1 horsepower is 745 Watts. So that gives you about a horse’s ankle worth. 1 catpower, maybe.

      I’d save the solar / battery setup for keeping your camp lit up and music playing. Your components are all mismatched for each other, and for your application. If you really wanted to, you could perhaps electrify a kayak but the solar panels would have to stay on the bank, you’d need way too big. You really need some plans and advice to follow from someone who’s done it before.

  12. Success!!! my sewing machine motor has more than enough thrust at a 1/4 of it’s power rating (Tested it in the sink) so my two small 12 volt batteries should last about 10 hours, if I step it up to the full 24 volts my Kayak will be going like a bat outta hell…now to make a mounting bracket…and my solar panel has more than enough power so on sunny days I have no range limit

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