Electric Jet Ski Conversion

[DaveR]

Originally Posted by leonardv9240

hello i am the owner of enve marine, we build a 10, 12 and 20ft hovercraft and are getting into larger custom yachts that are hybrids, I believe their to be a market for what you are doing with this electric drive, I believe you need lithium polymer batteries which have have great connections for,, if you can get one proven , I am sure we could do something on a larger level, we are looking to mass produce a electric waverunner , with performance and good battery life. Environmentally friendly ,, respond back and well get to talking if their is interest,

I agree with Leonard, hybrid boats will be wave of the future. I have been designing and consulting in hybrid vehicles and power generation since 1998 and the advantages that we are seeing with land base applications will be just as much as an advantage in marine applications. Leonard, if you’re serious about hybrid marine applications send me a note. Your links on your website were not up and running yet to contact you.

All I can say to the originator of the thread is keep working on your boat project as you first thought. If you keep working on it you'll find innovative solutions along the way.

Over the last 20 years I have generated many patents from my ideas that companies have made many millions from and most of them I was told by others that it either won't work, we tried it before, there is no market for it, or you just are not an expert in the field to understand. Well they did all work and the companies have made a lot of money and we advanced our products along the way.

Things change as the years go by, technologies change, methods for solutions to problems change. If this was 1960 every engineer would have laughed at the design of the stealth air plane saying you would have about as much of a chance to make a brick fly. Technically a Stealth shouldn't able to fly, but the modern advances in control systems and feedbacks controls allow the computer systems on board to control the flight surfaces in such a manner that it does fly.

Stick with it! You’ll find a solution that works for you and your kids and you’ll have fun along the way. Sure you could use a gas engine, but that is not the challenge you were seeking. I agree with the one post, use the gel mat batteries at a minimum because of the leakage of a standard lead acid battery.

Please let us know how it all turns out. I for one would like to see a picture or two of the project, it sounds cool.

[marshmat]

I would love to see what the thing could do with the Li-Poly battery pack from a solar car. Those things have some serious power density (5 kWh plus from a 25-30 kg pack).

I seem to recall reading, Dave, that Lockheed's aerodynamicists were alternately laughing and cursing at the F-117's originators throughout the concept phase. Right up to when the thing left the runway, a lot of them really thought it had no hope in hell of flying. But it flew anyway (albeit with an awful lot of help from the computer).

Looking forward to seeing some updates on how it's coming. I still don't think it's a good hull for it, but I'm curious to see how it turns out if the project's still on.

[electricman]

Im doing a conversion to electric on a polaris 650 ski right now..Im running a 6000 RPM electric motor,direct drive in mine..This should give me close to the factory speed on the water..My motor is running on 36 volts..Lithium ion cells..

[stopoilwars]

I Have A Polaris Sl650. I Removed The Gas Motor. I Am Planning To Use The Same Jet Ski Prop. I Need To Match The Shaft On The Jet Ski To An Electric Motor. What Should I Do. So Far I Bought 2 12 Volt 90ah Sealed Agm Batterys. I Have Been Using A Electric Motor With 30lbs Of Thrust To Push My Shuttle Craft And Detachable Polaris Slt 780 But The Motor Could Only Hold Me In One Spot Against The Current Comming Out Of The Harbor In Long Island Sound. Very Dangerous Situation If I Did Not Have Gas To Back Me Up........i Love The Way The Shuttle Craft Moves With No Noise When Its Powered By Electric. Ant Wait Ill Next Season....i Will Work On The Conversion This Winter......again Please Help!!!

Ev

[marshmat]

Hi Ev,

The power absorbed by a jet pump's impeller is proportional to the cube of the shaft RPM. You might find that some impellers have a "power rating", eg. 12 kW. This is, usually, the power the impeller will absorb at 1000 RPM. How much power will it absorb at 3000 RPM? Take the cube of the ratio: (3000/1000)^3 is 9, 9*12 is 108. So that impeller absorbs 108 kW at 3000 RPM.

If you know the peak power of the jet ski's old engine and the shaft RPM at which that occurs, you can reverse the calculation to find the impeller's power absorption at whatever RPM you like. Or, you can find the impeller's power rating, and use the ratio of your motor's peak output to the impeller's power rating to calculate the ideal shaft RPM with your electric motor. That will allow you to select a suitable belt or gear reduction ratio between the new motor and the old jet pump.

If you just hook it up direct drive to the existing impeller, and the new motor's power/rpm curve is significantly different from the old, you'll be very disappointed. Doing so could overload the motor and prevent it from reaching the RPM at which it makes its rated power- all you'd get is a lot of heat, and terrible performance. Impellers have to be matched to the RPM and power level at which they are operating.

A further note; please do not capitalize every word of your posts. Proper sentences should be used on here; capitalize only the first letter of each sentence and the first letter of any proper nouns, etc.

[stopoilwars]

I am looking for a water cooled electric motor that does 8000 rpm..........any suggestions? The only motor i found was from green motor sports based in theU.K..

Please Help

Other companies have said " it will cost 50,000 to re-engineer the warp 9 motor to function under water.

Whoever has a submersable electric motor will rule the EV marine world!!!!

[marshmat]

I thought you were talking about converting a jet ski to electric. Why would you need an underwater, 8000 rpm motor? If NetGain's WarP9 is about the size you're thinking of.... well, that doesn't match with what you just asked about. Can you post a little more detail on what you're planning, how much power you're trying to get / how much speed, what you've already decided, etc?

[stopoilwars]

I Have A 1996 Shuttle Craft Jet Sport Boat

I Have A 1994 Polaris Sl 650 Hull And Jet Pump.

I Have 2 90ah 12 Volt Agm Sealed Batterys

I Was Thinking Of Converting The Shuttle Craft By Placing Electric Motors In Either Side And Putting Props On Both Sides.

But, First I Want To Do Testing With The 1994 Sl650
I Already Have The Hull Nice And Clean. The Dirty Gas And Oil Engine Has Been Removed. I Need Someone To Help Me Adapt The Shaft On My Jet Pump To The Shaft On A Electric Motor. The Removed Motor Was 100 Hp.................the Motor Will Get Wet After The Installation. I Want The Best Motor For This Aplication. A Sealed Or Submersable Motor Would Meet My Needs....any Suggestion? Wether Its 2000 Rpm Or 8000 Rpm I Just Want Something That Will Not Fail If Placed Underwater.

Please Help

Ev

[RSALVAREZ]

some one still workimg with the electric watercraft? i use a gokart motor direct drive on a js 550 sx hull and works great with 4 optima battery´s for 40 minutes at full or wot, then recharged with solar panels in 2 hours, better batty´s will perform longer, i did no did many matematics, just disasemble an electra motorsports gokart and install all on the ski jus for experiment and work

[tdc1258@shaw.ca]

The thing every one is forgetting is that an electric motor is all torque, it will produce the same torque all the way threw the rpm range, that is what makes it so much better than gas.
Another thing is it uses amps instead of gas, the amps go down acording to the amount of torque you need, less torque less amps, and longer charge life.
if you want more torque reind the motor with more windings and if you want mor rpm less windings. just remember the size of wire designates the heat at wot. The smaller the wire the more heat, but you can use more windings. the bigger the wire the cooler the motor but less windings.
Now if you dont want to rewind the motor the use a bigger wheel it will deliver more water and the electric motor will handle the torque needed to spin it. its just like a car if you want a certain speed you have to figure wheel size, how far do you want that vehicle to move with oe revolution of the motor, then what power do you need to turn it. Stop trying to match a gas engine to an electric motor, it will just confuse you because there is no formula that you can use to do that. Its all speculation.
Either try the hit and miss metod or figure it from the start. How much water do you want to move to get this boat on plain, what size of prop do I have, how fast do I need to turn that prop. how mch torque do I need to turn that prop at that speed, rpm is just the amount of volts you want to put to the motor, more volts more rpm. Keep in mind that the higher volts you put to a motor at full torque meens the motor gets hoter.
If you can keep the motor cool you can put all the volts you want to it and it will just go faster.
Another thing to rember the higher the votage motor you use the lower the amps, the lower the amps the longer the run time.

[Jason Adams]

These folks are all correct. A jet propulsion system needs RPM not torque. The truth about electrics is they have a torque advantage over gas but when used in boats special low speed props are usually employed to take advantage of the electric motor's torque advantage. Launches with low resistance displacement hulls are employed as well.

You are trying to use a planing hull with a jet propulsion that is not suited to low speed operation. If you are married to the idea of using this jet ski with electric the idea of using a trolling motor and pulse-width controller is about the best idea that has been put forth already by a wise forum member above.

Save your money and effort go gas or trolling motor with this hull.

[canadaru]

i have recently done this with a Kaw. 650sx stand up, i used a electric radiator fan out of a 1989 VW Golf GTi that had two speeds, the lower speed is always on and i have the second speed connected using a relay activated by the start button. i used two car batteries connected in parallel and a solar charger mounted to the arm of the ski. I wrapped the motor with copper tubing and then wrapped that in Dynamat (a sound proofing material available at best buy, i used it b/c it is mostly a tar-like substance with metal backing that provides great insulation). I connected a small self priming 12v water pump to the copper line and used existing water taps to provide cooling for the motor The batteries last me about 30 minutes and takes an entire day to charge by solar or can be hooked up to a quick charger and done in about an hour. I also have a small lawn mower battery attached via a secondary battery switch available at advanced auto, i installed this for "emergency" power so that i dont end up completely stranded. I plan to install a digital voltage readout on the shell somewhere. The ski isnt very fast but its still very fun. The pickup is not anywhere as good as gas. If you connect the batteries in series the motor is much faster thus making the ski faster but the battery life is reduced to about 10 minutes and im not sure how safe it is for the motor. I also have a fan motor from a 96 Passat GLX that has 4 speeds but i have not tried it yet

[gonzo]

That seems like converting a Ferrari to pedal power. The purpose and fun of a jetski is to go fast and maneuver aggressively. Otherwise, why have and unconfortable seat and a passenger behind who you can't talk to without contorting?

[Rangerspeedboat]

Instead of converting a jetski to electric, just put a smaller motor on it. A little horizontal shaft engine connected with pulleys or direct drive. Theres no reason for overcomplicating things with electric motors.

[canadaru]

well i converted mine with things i already had, my motor had gone bad and i live on a lake that does not allow gas powered vehicles so its all a plus for me. Sometimes its good to be green