Thread: The First electric jetski!
10-29-2009, 10:06 PM #1
The First electric jetski!
Hmmmm.interesting thought! I do have this 94 sl sitting around basically junk. Well it needs a engine and complete cdi to run it again. I was thinking how could WE-lol- make this thing run on an electric motor! Or is there a way to make like 4 12-volt batterys into a A/C and run a fat electric motor in there and connect it to the drive shaft somehow? welding ete... A totally silent jet ski! I wonder how fast or quick it would be? Plug it in and your ready to go the next day! No gas! Allowed on quiet lakes! lol
Any thoughts? How "fast" is a electric motor like a 1 horse? would it even move it? I know when ya turn one of those 1 hp bench motor, man that thing spins fast! Probably not enough torque to move the water, impellor and weight of the craft. But I dont know for sure. You'd have to make a mock up of just the motor and impellor with shaft and try it out. Yikes, that would be dangerous! A big ol electric motor with a 2 foot shaft and a killer blade on the end of it. Damm that would be good for mixing jungle juice in a barrel! lol
10-29-2009, 11:02 PM #2
electric motors have constant torque.. at 1 rpm you have the same torque as 1000 rpm.. so yo can run an aggressive impeller.. the bigget challenge is going to be finding batteries that will deplete and recharge without being destroyed (lithium ion..). which is going to be expensive. it can be done but without cutting edge batteries and deep wallets you probably will be limited on your success.. maybe take a prius battery and similar motor.. then you have corrosion issues, electrolosis.. anything can be done but how much are you willing to spend..
10-29-2009, 11:09 PM #3
Sure, it's possible but I don't think you would have much longevity. Also, I think you would want to stick with DC motors because you can ramp those up to max RPM whereas an AC motor is 0 to max instantly. If you had a motor with any significant power I would be concerned about cavitation.
You would also be adding some mongo weight to the ski. I would say the engine, exhaust, and a full fuel tank might weigh around 200 pounds. Even to get 48 volts you'd need to hook 4 batteries in series at 70 lbs each. So right there is 280 lbs. The motor, if it has any decent power, is going to be about 50 lbs or more. Basically, you're adding a whole bunch of weight to the ski.
Now, consider what would happen to all those electronics if you roll the ski Bye Bye birdie!!!!
Also, DC motors don't turn a whole lotta RPM, so you would need some kind of reduction gear, like a 2:1 or a 3:1 to get the drive shaft spinning fast enough to get up some decent speed.
Overall, I don't think you'd have a ski that would go very fast or for any reasonable length of time. Now, having said that, it would be kinda cool to build one just for grins. Maybe a sort of water scooter just to putt around Hey, if ya got the time and the cash, why not?
10-29-2009, 11:14 PM #4
How about nuclear power?
I predict that cars are eventually going to be nuclear powered. This will eliminate the pollution problems as well as the diminishing supply of fossil fuels. All you would have to add is water!
10-29-2009, 11:15 PM #5
10-29-2009, 11:42 PM #6
I'd love to find out the range of that thing.
I know of some research done about hybrid / electric watercraft and the conclusion was that is is highly unfeasible due to the power requirements. Electric snowmobile... now were are talking, but watercraft ... i doubt it.
But you don't really need to be an engineer to figure that out, you can get a pretty good idea of the power requirements from the fuel consumption of any skis.
10-30-2009, 12:25 AM #7
- Join Date
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haha anybody catch that sounds of it comeing unhooked , at 1:03ish it sounded like a real one at that point maybe a quite real one
10-30-2009, 12:35 AM #8
Here ya go, it's a long read, but some of these guys are powering some stuff with lithium ferriite (A123) cells, like from a dewalt 36v drill
yer gonna need a big speed controller, preferably for a brushless DC motor. prolly a gearbox as well to step up the impeller rpm, but you could use a crazy tall prop since the motors make so much torque. for the gearbox, I would look at an arctic cat sled gear box. lite and compact, able to change gearing easily. you can hook it up backwards if needed to make the gear ratio work right for the elec motor.
The problem with the a123 cells is the low MAH rating, I think its like 2200, so you are gonna hafta run a couple packs in parallel to get time and distance out of a charge. The place to start would be to see what kind of gearboxes and ratios would be available to reach a target prop rpm for cruising, then you calculate backwards from there to figure out motor KV and voltage required to spin the motor to the right rpm.
really quite easy to calculate, but pretty hard to build.
10-30-2009, 02:49 AM #9
Nice job beaching the ski at the end. DOH!!!
10-30-2009, 06:57 AM #10
Did you see how fast that was? lol That was neat but that ski is way to big for this project. I was thinking along the lines of 4 big sea-gels,a inverter and a 1 hp motor with a potentiometer as the throttle for it. Everything else the same pretty much.
Weight wise would be 4-65 lb batterys, ! 15 lb 1 hp motor and the coupler and shaft. A few wires here n there. thats 275 there abouts. Could you just adjust the thrust with a dump on the back nozzle to redirect the thrust? Kinda like a reverse cover or something like that? to keep it from movong forward?
Lithiun ion would be the way to go on this but too pricey! D.C. motor would be better to control too. The gear reduction could be made for it. doesnt sound impossible.
Well just a thought to brainstorm on. Lets hear what others have to say or think about this stuff!
Basically it will come down to how fast you expect to go and for how long. no speed laws will be broken! or records.! And like ya said, it ya flip it ,your done.
Maybe in the future, they will have 100 mph jetskis with lithium batteries in them than run a 100 miles! That would keep the green people out there happy! no noise or gas or oil burning.
Howcould you connect the Impellor to the shaft from the DC motor? IT has a slot on the shaft and the other has a spine?
If you used a reduction gearbox, could that be fashioned to accept a dc shaft?
Ok how about this for simple.. Just cut the end of a bad crank where the driveshaft goes into the splined open shaft of the crankshaft. That way you have an instant coupler. Then take a pulley and slide that on the dc shaft and weld it on there. Then weld the pulley and the other end of the coupler ya just made and Poof! , it's all connected!. well maybe use a steel shim or whatever instead of a pulley. I was just trying to think of something that would just slide on the shaft to accomodate the slot in the DC shaft.
Anyone with me so far? So theres your motor/impellor pump asbly already done. We'll worry about props/ pitch later. You would need to make a cradle for the motor to secure it in place with adjustment for alignment too left/right/up/down/fwd/aft/pitch too. But I guess that wouldnt be too hard. .you could use a motor off a 5 hp compressor and use the frame that connects it to the tank as a cradle for the motor in the jetski, then bolt it down once aligned. batteries? heres the biggie,man those things are heavy too. Hull would have to be striped out inside. everything goes,lol gas tank,hoses,electrical,rubber hoses.holding compartment,would ya need a fire extishgusher still by law? I doubt it.
Would ya put 2 up front and 2 in the back one the sides? Use like #2 gauge subwoofer wire. Would you change the voltage or would you want too? or could you? would that destroy a air compressor electric motor? I'm cluless when it comes to electrical stuff like this. Put them in series or parallel? I'm just trying to use stuff around that I have. I really dont want to spend lots of money on it. just for fun.
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