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PostPosted: November 29, 2014, 1:34 am 
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I have been planning out a BEC build 3 wheeler on paper with drawings and such while saving up the funds to get the pricey parts and over the thanksgiving holiday i seen something that threw me for a loop that got me to thinking.. I was at the Flying J in GA truck stop getting diesel when this Nissan Leaf pulled in with this trailer device and stopped at the fuel pump. The guy gets out and undo's a few things and next thing i know he is pumping gas into this trailer device, i walked over to him and asked him what it was and he said is was an EV Extender, that it is an Generator that is supplying voltage directly to the car's battery bank for extended trips... It was nothing fancy like in the picture below.. it appeared home made, but after about a 5-7 minute conversation i got to thinking that this idea would work on an EV powered build for longer drives, the biggest expense in the list of parts i gathered for EV route build was the dang batteries because i was doing a price out for 80 mile roughly range if i was to go EV route and the cost just was insane, so i have always defaulted back to the BEC setup.. but after seeing this the EV idea is coming back to the thinking board.. and doing some readings i am finding that some of these EV Extenders that EV owners are building can generate enough energy to power a Nissan Leaf down the highway and over time charge the batteries to full on just a gallon of gas over 2-3 hours they claim.. because the amount of energy being used on the highway in a Nissan Leaf is 250-380watts....

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So the idea i am thinking is... Since i am truly only looking to get enough juice out of a battery bank to drive it to work and back safely with a few miles to spare, i could reduce it down to something like 20-25 mile range since my round trip to work and back is about 11 miles.. this would dramatically reduce the weight of the vehicle and reduce the cost of the build by nearly half the original cost.. and still have enough energy for a few 1/4 runs or autocross runs....The idea would be to use something like a small Micro-Generator to supply power for long distance riding.. on like a single wheeled attachable trailer that would pivot off the rear tire... I currently have one of those Harbor Freight 900watt generator deals that i picked up for $50 bucks with coupon one day that i use for camping with the family from time to time that gets about 8-10 hours of run time on half a gallon of gas.. i think its rated at like 5-6 hours of run time at 400 watts and 2-3 at 800 watts..

What do you guys think.. i have been thinking of using 2 smaller electric motors mounted at the front 2 wheels for FWD propulsion for maximum traction on a 3 wheel design and just have a weight bearing 3rd wheel in the back..


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PostPosted: November 29, 2014, 1:47 am 
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Gonna need a wayyyyyy bigger generator. 1 kw might get you to oohhhhhhhhhhh 5 mph pushing 1200 lbs. Maybe, with enough gears and a couple of shifts. ..
1 kw on an electric scooter is good for about 27 mph with the right size tire on a long flat road.
There's a lot of switching back and forth between power formats there, more than a little inefficient in the 25+ mile range.
Maybe if you used an old nat gas fired 20-30 kw turbine converted to lpg and put that in the trailer, those are pretty small.

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PostPosted: November 29, 2014, 1:57 am 
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Here's a currently available product. 15 minutes to put in a charge equivalent to 20 miles of driving. http://www.evmobilecharging.com/video.htm

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PostPosted: November 29, 2014, 12:06 pm 
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because the amount of energy being used on the highway in a Nissan Leaf is 250-380watts....


I think you are missing a zero and even then something is not being accounted for.

1 HP = 745.7 watts. Watts are the metric measurement of power and what you will see cars described with in advertisements in Europe.

You can expect the pricing on all of this stuff to be going down. This is certainly doable and having a modest range requirement helps a lot. You can also look at this as being a solution for various driveline issues like rear end ratios, forward/reverse, placement etc. The electrical cable to the motors is easier to route then a driveshaft. Once you start thinking hybrid, you only need a very short range and a generator good for the max speed you desire on level ground.

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PostPosted: November 29, 2014, 12:22 pm 
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storx wrote:
... because the amount of energy being used on the highway in a Nissan Leaf is 250-380watts...

Uh huh. A typical car requires about 20hp to maintain highway speed. Let's be optimistic and say that due to great aero, the Leaf needs about 1/3 of that, or 7 hp. As noted, 1 hp is 746 watts, so that's 5222 watts. But that assumes 100% efficiency, which is never true, so figure an honest 6000 watts, plus reserve, or maybe 8000 watts real world. So, yeah, ditto on there being a zero missing.

A hot button for me has always been how EVs are marketed and discussed. It's almost a religion, where no one challenges the numbers for fear of being cast as "The Enemy." Just as bad, errors (which should equally be above and below actual facts) always end up on the beneficial side, making one suspect the data's been cooked. This isn't pointed at the OP, but at a market that's clearly running as much on marketing as it is on electricity.

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PostPosted: November 29, 2014, 1:01 pm 
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I do apologize, i was a little tired and under the influence when i wrote this posting.. they state over on the Nissan Leaf forums that the Nissan leaf uses between 280-350 watts per mile, with the average person pulling 302watts per mile. I am not sure how that converts over to generator output numbers as they do not specify that but they talk alot about DC charging at Battery voltage with 8-10Kwh generators.. One of the common generators tossed around on the forums that people seem to favor is this little guy...
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24-60v DC Generator 10KW Gas
Max Output: 60v @207amps (11Kwh/min continuous)
750x550x560 @ 90kg
Peak to peak noise (0~20MHz) <200mV

They state that this generator wired up to a step setup to push it to 360 volts allows enough output for HIGHWAY sustained power... I am no expert to understand how this generator is powerful enough to sustain highway driving up to 75mph..


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PostPosted: November 29, 2014, 1:08 pm 
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Is this a cost saving idea or an earth saving idea? Because you'll probably produce fewer total harmful emissions by driving a modern gas powered car all the time than even occasionally using a range extending generator on an EV.

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PostPosted: November 29, 2014, 1:49 pm 
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I am aiming at a Compact single seater like the Scorpion P6 setup but EV instead of Gas powered and multiple posted weights for them is 695-725lbs wet

Doing a little research today, from what i understand the NEWER 05+ Yamaha R1 engines weight is around 190-200 lbs with the R6 engine only weighing about 7 lbs lighter...Correct me if im wrong

So 725lbs - 190lbs puts you at 535lbs
So 535lbs - 5 gallons of gas (44.5lbs) puts you at ~490lbs
So 490lbs - cooling and oil systm (~30lbs) puts you at ~ 450-460lbs

So going off those ROUGH calculations the rolling chasis without the gas transplant would be 450-460lbs and im pretty sure a bunch of weight is not being removed out of unknown..

Not a final kit, as i am still learning about EV's but most EV motorcycle conversions use 48v brushed motors for cheapness and in most sport bike configurations they are using the 8-10hp DC motors and they claim pretty quick acceleration numbers with those engines at MAX amps...but i am thinking of going dual smaller motors for more traction doing FWD configuration like they do on the EV autocross circuits in Australia...

Start Weight ~450lbs
2 x DC Brushed Scooter Motor 48v 5hp continous 13.5hp peak @ 300 amps 24.8lbs ($195) ~50lbs @ $390
Ecomodder DIY Gazzila 600 Amp Motor Controller 4.4lbs ~$75
15 x 3.2v 40Ah 1.5kg $52 (22.5kg (11.25lbs) @ $780) for 25.6 mile range
Image

Which puts it at the 550-600lb range without anymore weight reduced from the vehicle.

If i listed or calculated anything wrong let me know and ill correct it.. this is still a learning experience for me..


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PostPosted: November 29, 2014, 2:15 pm 
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Driven5 wrote:
Is this a cost saving idea or an earth saving idea? Because you'll probably produce fewer total harmful emissions by driving a modern gas powered car all the time than even occasionally using a range extending generator on an EV.


I am not looking to save any money here honestly and the power to charge it would be free since i have solar electric on the house is just a bonus.. i am just trying to figure out a means of getting more traction out of a ultralight weight sports vehicle while still keeping the Motorcycle classification since there are a few people in Florida that have had issues with registering and insuring VW street buggys and locost builds that i have come accross or the insurance is just really expensive... custom motorcycle insurance is very affordable through most BIG name insurance companies..I have a friend who has a custom hand built trike 1 front/2 rear harley powered motorcycle that he pays around $100 every 6 months for liability.... i am not looking to do 1/4 mile runs and i doubt i would do any major AutoX racing.. but i do occasionally attend AutoX car meets and sometimes wish i had a vehicle capable of doing a few times laps out of fun...Also i have become more and more attracted to the EV vehicles.. I have driven the BMW i3, Chevy Volt, and Tesla Model S and they all impressed me tremendously on the torque and acceleration they have.. The i3 was sooo fun to drive with the Instant torque combined with low weight chassis...so i just imagine how much more enjoyable it would be in a 600-700lb vehicle..

The 25 mile range would give me enough range to do like 90% of the driving i plan to use it for while keeping the ultra low weight idea and for the final 10% i could attach like a 50lb trailer/swingarm generator setup for longer rides that take me outside the 25mile range with the benefit of the gas generator being something i could easily order new for few hundred bucks or work on if i build my own DC generator using off the shelf common parts.

The other reason for EV vs BEC is because of the issue of traction of the 3rd (Power wheel) in gas engine configuration, i have seen the Slingshot in person and under moderate acceleration there is no traction in the rear and when they whip around the corner the rear has even more traction problems.. so i figured the easiest way to supply power to the front wheels would be an EV based setup which would give you TONS of traction in such a small vehicle...
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PostPosted: November 29, 2014, 3:06 pm 
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EVs and maximizing traction don't seem very related, but I get why you're asking.

Somewhat related, many or even most autocross organizers won't allow three-wheelers because it violates their insurance, which typically covers only cars (4 wheels).

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PostPosted: November 29, 2014, 3:33 pm 
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Good points on your design choices.
I particularly like the idea of a FWD tadpole with one motor per wheel, I've long felt that would be an easy way to put together a drive train.
Hub motors, inboard with direct drive or a reduction box?
Hub motors and direct drive will give you a higher top speed with a cost in acceleration and higher amp loads accelerating from a stop, reduction boxes the opposite.
Hub motors are heavy but you can get a 6 kw on a GM pattern online easily enough, its just a huge amount of unsprung weight in my opinion.
A fair number of scooter motors in that price range are hub motors which require both sides of the shaft to be supported and have a reaction arm to hold the body in place. .. Which motors are you discussing?
A smallish motor, shaft inwards, to a chain reduction with the output facing outwards would give a longer CV shaft which is a good thing for suspension travel and you can tune the reduction to match tire size.
That way you can also put the motor way up in front so it gets more air flow for cooling.

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PostPosted: November 29, 2014, 4:13 pm 
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KB58 wrote:
EVs and maximizing traction don't seem very related, but I get why you're asking.

Somewhat related, many or even most autocross organizers won't allow three-wheelers because it violates their insurance, which typically covers only cars (4 wheels).


thanks i was unaware of that, but the autox events i normally attend are created by local car clubs in parking lots or like universities or small airports in most cases.. so i have never seen restrictions on the vehicles used.. I kinda want to stay with Motorcycle classed build because i miss riding... but since spinal surgery and such my back cant hold up to the hunched position on any kind of sport bike and you cant exactly ride them aggressive while holding your body upright while on the seat.. I have a KTM Enduro now and my back starts to kill me after about an hour of dirt riding.. but just cruising on it back home from the riding area i am fine with the upright riding position.. so the sitted motorcycle setup with 3 wheels gives me motorcycle size and acceleration with amazing cornering all from the upright sitting position..

Am i wrong to think i could push the weight of the setup closer to the 500lb mark based off the weights of the EV components that are going to go into it? just looking over some EV Gokart builds and they are getting pretty insane power out of a very light package...

Here is one that produces 128hp 481ft/lbs on an 208lb go kart... with an 25km battery range and peak speed of 138km/hour using twin motors and single motor controller
2 x motors 54.1lbs
228 x 280gram batteries 31.92lbs

[youtube]https://www.youtube.com/watch?v=zI0TNk5gLbU[/youtube]

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PostPosted: November 29, 2014, 4:28 pm 
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oldejack wrote:
Good points on your design choices.
I particularly like the idea of a FWD tadpole with one motor per wheel, I've long felt that would be an easy way to put together a drive train.
Hub motors, inboard with direct drive or a reduction box?
Hub motors and direct drive will give you a higher top speed with a cost in acceleration and higher amp loads accelerating from a stop, reduction boxes the opposite.
Hub motors are heavy but you can get a 6 kw on a GM pattern online easily enough, its just a huge amount of unsprung weight in my opinion.
A fair number of scooter motors in that price range are hub motors which require both sides of the shaft to be supported and have a reaction arm to hold the body in place. .. Which motors are you discussing?
A smallish motor, shaft inwards, to a chain reduction with the output facing outwards would give a longer CV shaft which is a good thing for suspension travel and you can tune the reduction to match tire size.
That way you can also put the motor way up in front so it gets more air flow for cooling.


I wish i knew how to use CAD to display my mind.. what i am envisioning is placing the 2 EV motors at the VERY front of the frame facing outboard, then use simple chain and sprocket technology for cost to power CV shafts to each front wheel allowing the use of standard FWD hubs... could even take advantage of the All Aluminum FWD hubs you can buy for Honda's for weight reduction that are already on the market. Then use BMW i3 size wheel setups for reduction in rotating mass while still allowing the use of a standard road tire.. since the BMW i3 wheels are Super Light...19x5 wheel and tires are said to weigh only 25lbs total..
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PostPosted: November 30, 2014, 1:41 am 
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storx wrote:
thanks i was unaware of that, but the autox events i normally attend are created by local car clubs in parking lots or like universities or small airports in most cases.. so i have never seen restrictions on the vehicles used..

Yep, that's pretty common. But have you ever seen motorcycles actually run at them though? Because that is what you are technically proposing. In all liklihood they run similar critical rules and restrictions as the bigger clubs, even if not the same exact classes, simply to make it far easier to secure the necessary event insurance.

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PostPosted: November 30, 2014, 5:33 am 
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Frazer Nash are building electro/petrol taxi cars, they have a small test facility not far from here and I can confirm these things
dont hang about. I think they run a tiny petrol engined generator that just tops up the battery packs with no direct drive from the engine.Go for it :)

http://www.newmetrocab.com/

http://www.frazer-nash.com/metrocab/

Bob

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