Chainsaw flashlight (gas engine powered spotlight)

I've been wanting to try this for a while as crazy as it sounds; make a mini electric generator with a small engine and a treadmill motor, add this to some car headlights and you get one very loud flashlight/spotlight. 

An electric motor is basically a generator and an electric generator is basically an electric motor. The chainsaw provides the power to spin the motor and booyah....electricity. I'm sure all kinds of electrically proficient peeps will shake their heads at the methods here, but it's all just fun, nothing serious. 

(I want to add that I squeezed this project out to meet the flashlight contest deadline; it still needs a voltage regulator, a protective shield for the chain and sprockets, plus some adjustments and fancy paint work.)
Final adjustments to this machine, a voltage regulator is not needed if the saw throttle can be incrementally adjusted with a hose clamp. Hook up a multimeter and set the throttle before plugging in the light. Also the gearing in this instructable is way too high, the DC motor sprocket needs to be much larger to slow it down. I can hand turn this DC motor and get 2 to 3 volts, so the chainsaw should barely be running above idle to get the right voltage. This project is a little dramatic; maybe next time I'll use a lawnmower engine ;).

Here we go:

Materials:
1 old chainsaw
1 treadmill motor (DC permanent magnet motor)
1 one-piece 12 volt car headlight bulb
odds and ends tubing, wires, switches (see detailed steps)
bicycle spockets
bicycle chain
motorcycle voltage regulator
scrap wood and screws

Tools:
wrenches
screwdrivers
welder or someone who can weld a sprocket to a chainsaw clutch and treadmill motor flywheel.
jigsaw
.....

(Extra: With a few alterations, this project can be made into a mini generator or a go kart.)
Warning, this can be dangerous. I'm not liable for any injuries or whatnot incurred using the shown techniques. At your own risk and stuff. 

Step 1 Remove sprockets from bicycle and line up best fit

I needed a bike sprocket on the chainsaw and on the electric motor. An old bike somebody threw away worked well for the parts. I used the smallest outer sprocket on the hub to attach to the saw and the larger set behind it for the DC motor. Don't ask me how I got this apart, I'm not a bike mechanic; and all that is left of the wheel is a pile of spokes, ball bearings, and cut up pieces of the axle hub thing. ;)

Comments

[zilcho]

See the problem with this is that most of the time when I use a flashlight its at night and my neighbors would get pretty mad if I fired up an old chainsaw engine every time I needed to see.

[super tubes]

vrom vrom, im goin to blind you!

[lukeyj15]

May I suggest that you replace the permeant magnet motor with a internally regulated car alternator. That way, you will be putting out 13v no matter what. The only problem is a small amount of power is required to energize the fields.
My 2c

[adelfino06]

Also also, at a constant 13Vdc hi intensity chip LEDs become an option (an expensive one though). that would be A LOT of lumens!!

[SirStokes]

Only in America does one need gasoline to see in the dark. Awesome instructable!

[Terivia]

That is one BA flashlight, i want to bring on a boyscout campout. "WOULD YOU TURN THAT OFF?!?!?" "No, we need it to play magic"

[bombmaker2]

I was thinking:
"WOULD YOU TURN THAT OFF?!"

"NO!!!! I got to a good part in this book!"

[quadracer]

You can adjust the carb so it idles high enuff to engage the clutch.

[2 stroke]

yo man is that an princess auto welder by the looks of the gun and ground clamp looks like the flux wire welder they have if so i have their 70 amp stick welder

[nedfunnell]

Awesome build!

[bart245]

That little flashlight project you built there is awesome! Great job!

[wizworm]

You need to take that to Burning Man, that would be a hoot

[snowluck2345]

(removed by author or community request)

[SwaggeringPagan]

Who cares about practicality, gimme internal combustion! Very cool survivalist/dieselpunk rig.....

[TechDante]

this would be perfect for a horror film just the effect of building it then moving around a dark house with the pulsing light and the posibility of the motor cutting out (for teh film of course) to plunge teh character in darkness only for a shocking reveal make this a perfect prop and effect well done

[shortw]

Rob If you use a higher watt bulb ( high beam) 55watts, the bulb is less likely to burn out. Or use 2 bulbs or more. In addition, if you add a 12 volt battery and hook it up parallel to the light with respect of positive and negative, the battery would keep the voltage under control. But you have to add a switch right at the generator/ motor so if the chainsaw light is not in use the DC motor can not drain the battery. Using a battery with your chainsaw generator / motor has an advantage that you could run the chainsaw generator only part time and still have light, if the light dims down just start the chainsaw generator until the battery is charged again. Drawback using a battery with this; the battery could overcharge or heat up after a while. But if you match the wattage of the bulbs this is not a big problem. How many watts does your DC motor have? If you have only volts and amps listed you can calculate the watts. Multiply volt times the amps, that would be motor watts. Then since you use the motor as a generator you have some losses of about 60%-70%= about 65% average Now take the motorwatts and multiply by 0.65 that is about what your chainsaw generator can produce. For example if your DC motor says .... volt= 24V amp or A = 5...... 24 x 5 = 120 motor watts.......... 120 x 0.65 = 75 generator watts........ Now match the light bulbs to the wattage. Or in this case about 60-65 watts. Note: A chainsaw can make up to 12,000 RPM, do not turn the generator / motor with that high RPM it could and will fly apart. Stay within the RPM of the DC motor , that is listed on the name tag.

[robbtoberfest]

130 VDC and 6700 RPM, the other one I have is 90 VDC but no RPM listed. Next time building a system like this I'd probably use a direct drive instead of clutch and put a hose clamp throttle adjustment on the handle. I'm thinking of making a light duty welder with this, but I don't know what to do quite yet.

[shortw]

Use the 130 volt DC ( better choice ), or the 90 V DC and use a 110 volt light bulb about 40- 60-75-100 watts for it ( try and see). Use about 3/4 throttle for the 130 volt Motor, the 90 VDC motor should be about a 1750 rpm motor. With this high a voltage a battery will not regulate the voltage down to 12 volts.

[shortw]

Or the 130 Volt motor could make a good Wind mill or hydro project for 12v application ( low RPM ) . Yeah try it with a 110 volt light bulb, but you may to play with the watts. You got me exited now. Let me know.

[robbtoberfest]

Thanks for the tips. What if I used an old dead motorcycle battery, would that level the voltage?

[shortw]

It depends on the watts of your generator if you can use a motorcycle battery or if it would be better to use a car battery. If the alternator of the motorcycle puts out about the same as your generator I would say maybe yes.

We have to define ' a dead battery ' first.
A Battery That Will Take A Charge But Will Not Hold A Charge After A Period Of Time. This could be maybe used, but first when you start your chainsaw light the battery will not control or balance the voltage, but after the battery starts to create bubbles then it would be ok.' but you could start charging your battery first without the light, then later on switch the light on.
A Battery That Will NOT Accept A Charge( no or little bubbles) At All Can Not Be Used At All.
     It is best to use a battery that is good.
Or the better option would be to get a load control used for windmills.
    The best option would be to use a battery and a car alternator with internal voltage regulator this way you would not have to worry about volts and amps, but a alternator consumes about 40 watts to operate and to function and you need a battery for it to function properly ,  higher or lower RPM would not mater if you stay between 1200RPM ( start of full power) to 4000 RPM of the alternator.......
I like what you done here. Some folks my laugh at you, but I think it is very very very useful and a cheap generator. It could be coupled with a battery and a inverter ( 12V DC to 120V AC ) and it could be used as a emergency generator to have a 120V light and / or a 120 V TV powered..............
Remember 1 HP  = 736 Watts in electrical terms.
Car alternators have between 60 amps to 100 amps, so the max  with a 100 amp alternator would be 12V X 100A = 1200 watts minus the 40 Watts = 1160 watts output. But you would need a chainsaw with about 2 HP or better output.

[AAAdrian san]

thats kool maybe me and my twin juan can do that one day

[memano]

YA

[memano]

cool i have a neighbor that did that to a bike

[shortw]

What is the Volts and Amps of your treadmill DC motor ?
What is the RPM of the DC motor?
I like very much. There are many uses for it.

[treehouse24]

to the Creator this is old news, i mean as a bush man i was hunting one fall day when i left my lights on when i walked away from my truck returning 6 hours later it would not start as the batteries were dead , sitting there i thought it is a 30 mile walk or better yet charge the battery, i used my small chainsaw to charge the battery, taking off the belt from the alternator and the chain and bar from the saw i put the belt over the clutch , making sure the direction of travel was the same , i started the saw hand pulled the belt tight and for a few minutes turned the alternator to charge up, replaced everything and started the truck , when home with no blisters , here is your next how to instruct able, take care thanks, gord, as for the light not practical , yet make it for loggers in the dark led to run off the handlebar heater ,to light you work area, or even cooler two leaser lights triangulated to set at 49.6 feet to make one dot ( saving running a tape to measure the log and cut

[shortw]

It actually doesn't matter what direction the alternator is turning, either way you will have a positive or + on your positive lead or post and minus or - on ground / casing.
The alternator makes 3 phase AC power inside the alternator, that's why it would not matter what direction the alternator is turning . Then before leaving the alternator the power is going through 6 diodes or rectifiers that turns the Ac power into DC.
The reason i said '' actually '' is...
electrical  it don't matter , but you have a cooling fan on it and it matters what direction it has to run to cool the alternator under the hood under constant load and heat.
But for short run or with less load it would not matter either.
I never would had thought to use a chainsaw like that, that is very ingenious and easy to use when stranded.
Thanks for letting us know.

[Lorellai]

Many things on here are 'old news' but people still enjoy documenting their creations or instructing on their own particular way of doing things. Be nice, not jealous!

[treehouse24]

It was not my intention to make a negative comment on someone else's project , it was my intention to give him an idea to up his project to use of an application that probably has never before been demonstrated,such as the leaser lights triangulated to set a distance, but to others that may be old news as well as it was used on ww2 bombers using two lights to to set distance as well,so i am sorry if i offended anyone,

[Lorellai]

I apologise for being so tetchy!

[robbtoberfest]

Good ideas. I really like the laser light idea added to this to measure distance.

[jamilks]

Very Creative! Good for you! Should point out that one of the conditions is that you have a permanent magnet motor...dil-willy, the alternator is kinda a good idea except that you need some incoming power to initially set up the magnetic field in the alternator coils....That's why if you have a TOTALLY dead battery, starting a car with jumper cables may not always work...you need to get some sort of minor charge in the battery.

[mouse23]

Couldn't a n automotive alternator have been used? They have a regulator module on it already. And there are plenty of them around.

[robbtoberfest]

Could be used, but an alternator needs a battery to work....to power the electromagnet inside it.

[mouse23]

To clear up some mystery. From http://www.ibiblio.org/kuphaldt/socratic/output/dcgen.pdf : "It seems like we have a catch-22 situation here: the generator cannot output a voltage until its field winding is energized, but its field winding will not be energized until the generator (armature) outputs some voltage. How can this generator ever begin to output voltage, given this predicament?" file 00812 The answer is "Remanent Magtetism" which creates a little voltage which is fed to the field winding which then will strengthen the magnetic field, creating more voltage etc. Old timers (like me)may know that newly installed "generators" in old cars may NOT work right out of the box. They have to be momentary magnetized by applying 12V to the terminal. This will give them that remanent magtetism. Some new generators may come with remanent magnetisms of wrong polarity which creates all kinds of fun. Therefore one should always polarize one of those generators after installation.

[treehouse24]

i have a chainsaw the produce extra voltage to heat a handlebar enough to charge a an alternator

[havocgtr]

"an alternator needs a battery to work....to power the electromagnet inside it" Really??? I only ask because i have driven a few cars on just the power of the altenator (no battery installed was removed after starting the engine) (it was one of those hey yall watch this moments)

[shortw]

WARNING FOLKS :   do not do that....
Well, I done that too about 25 years ago, that makes me feel old.
In Idle it is ok. If you increase your RPM and turn your lights on You will replace all the light bulbs on your car and that was a old car without electronics.
Without the battery the voltage regulator can not function right and will put too much or not enough power ( volts and / or amps ) out or will be erratic in power output.
In newer cars it is a must to keep the power at steady voltage or amperage.
The electronic circuits could and will be destroyed if you drive without a battery.
How would you like to replace hundreds if not thousands of dollars worth on electronic and electrical items on your car? Like computers ( some Cadillac have 7 of them), sensors, injectors, ignition related items, speed control etc etc....
In the older days it was normal to remove the battery to see if the charging system would work, but mechanics back then would do it only in idle.
But those old days are gone with the introduction of the electronic era of cars and mechanics our days will not do this anymore in fear of destroying electronic items that keeps our cars running.

[Funk_D]

Regulator in the alternator, not the battery. lol.

[Funk_D]

I've wanted to make a generator from a weed-eater and an alternator for the longest time, and all my research says that a battery needs to be used for an alternator to work. If you don't, it supposedly can burn out that regulator that's inside the battery. I'd say if you ran a car on just power from the alternator then it might have been a model that didn't have an internal regulator, as some older ones apparently don't have them. Also on older cars, you don't need the electric system for them to run, just to use lights/radio/etc. Also, Rob, thank you for this idea! Like I said I've wanted to build something like this but never thought to just weld bike sprockets to the shafts and use a chain! I was thinking about some kinda direct-drive thing. I want to make a small generator for camping trips and this helps a lot!