Series AC Induction Trike

[JCG]

I've spent the last couple of months building a trike that could be considered on some level as a scale model of a series hybrid car - a separate project that I mentioned a few times before. So here's the full build thread, all in one post. I hope this fits without breaking it into smaller pieces.

Ok, the frame for the conversion is a KMX Tornado (~40 lbs, welded steel).

It is a strong frame, has a lot of available space:

and the square-section members are absolutely great for mounting things.

I got the trike from FFR, and I must say it was a great transaction - thanks very much Tom (VRdublove). I highly recommend these guys.

Since this was to be a series hybrid, the first step was to eliminate any direct link from the pedals to the wheel. A great thing about the KMX trike is the solid "bash ring" on the crank. It is of course set up for normal width bike chain:

I put washers in to space the bash ring from the crank sprocket...

And it was ready to accept heavier-duty ANSI 40 roller chain, which has the same half inch pitch (link spacing) as normal bike chain, but is wider.

I mounted a WindBlue permanent magnet alternator to the crank boom, and this will allow pedaling to deliver energy to the electrical storage system.

There is a charge controller as well, which prevents pedaling from overcharging the system. Not that I'm worried about that.

The entire storage system is 12 VDC. This allows for a lot of fun accessories, but most important are lights:

And of course you need GPS.

I also have a voltmeter "fuel gauge" on the front which I can look down to see, and the Cycle Analyst on the left hand steer bar.

Now, about the motor. This is the critical part from a design perspective. Here, you can see I've mounted a 2 hp induction motor (50 lbs) behind the seat. It is rated for 6 ft-lbs of torque and 1740 rpm at 60 Hz operation. It is wired for 230 VAC, 3-phase input.

The electronics for the motor (controller and power supply) are located right behind it. Here, you can see my shunt resistor along with the inverter 12V leads, and the three motor phase wires. It is so nice to not have to deal with hall effect stuff... wiring was simplicity itself.

Here's a better view of those electronics, stored in the rear basket on the driver's left hand side. The light blue plastic box is a Hitachi 3 HP motor controller (capable of up to 10 phase amps at 230 V), and the blue aluminum-cased unit is the 12 VDC to 240 VAC (single phase) power inverter. It is capable of 1500 W continuous. The little black boxes behind there are small 12V AGM batteries (in series). Their only job is to power the Cycle Analyst.

On the right hand side, we have a 12 V AGM battery, 35 Ah. One set of leads goes to the inverter, the other to the 12 V buses.

To multiply the torque to get acceptable acceleration and hill climbing, I placed a 60 tooth sprocket on the freewheel hub. Thanks to DrunkSkunk for that idea.

With an 11 tooth front sprocket,

torque is multiplied by around 5.45. Rated torque is 6 ft-lbs, but 150% (9 ft-lbs) is available at locked-rotor (dead stop):

So I'll get about 9 * 5.45 = 49 ft-lbs at a dead stop, which matches pretty well with my old BLDC hub motor. Top speed suffers, and at 60 Hz my 1740 rpm gets cut to 319 rpm at the wheel, so I extended the controller's frequency range to 100 Hz to boost the top speed from 20 mph to 33. You pay for that speed with some torque loss in the "field weakening" regime of course. I'll keep an eye on the speed with the Cycle Analyst.

I'm sure everyone saw the ANSI 40 chain on the rear two sprockets as well. Here's something I made that I'm kind of proud of - a threaded bolt-adjustable chain tensioner:

It allows me to get the chain tension just right without needing half links or scooting the motor around on its mounts. The terminal block allows you to access the + and - 12V buses as well as the Cycle Analyst electronics. Here, you see 7 +12VDC slots, 6 Cycle Analyst Slots, and 7 -12VDC slots from left to right. The missing two CA ports are for USB data collection. The plugs are for the lights and to disconnect the CA.

I have a (currently) hand-held throttle potentiometer (0 to 10 V signal) to control the motor speed remotely. I may mount this in the future.

Here's the overall product.

Some video: first, a spinup of the motor (effective 0 - 33 mph wheel speed)

[youtube]jPmKgRxWWnA[/youtube]

The same thing with a view of the motor phase current displayed by the controller. There's a decimal point between the digits.

[youtube]pdER4Bg16CA[/youtube]

I think about the present arrangement as the trike's "city mode," with probably lots of range, but relying heavily on the battery. This is the configuration I'm using for initial tests. When it is outfitted in "cross-country mode," imagine the following. First, replace the 12 V battery with three 16 V, 330 F ultracapacitor modules ganged in parallel for a 16 V, 990 F combination, which still fits in the right-hand rear basket:

That will be the electrical storage buffer. I'll have a rear trailer, the same one as the other bike had, to carry a small 900 W generator (25 lbs) and a battery charger, which can send up to 30 A to maintain 13.5 V over the DC storage system.

The generator runs for 12 hours on one quarter load (~225 W) using two thirds of a gallon of gasoline. The entire electronics system is 93% or better efficiency throughout, and the motor has an 84% efficiency at its rated load. If I run 25 mph at that power draw, that's close to 450 mpg. Pedaling could help that number too, I guess.

So, that's it. The AC motor has a lot of advantages; cheap, long life, easy control, good high-speed torque, no power drop at high speed. Thanks to safe for posting this plot in his thread on a separate board (and thanks for the brainstorming, too):

Link to MotoredBikes Thread

If you can handle the additional weight and space for the AC motor, it's a nice option. Safety is nice, too; although this system has some high voltages inside of it, the only voltage a user might possibly touch is 12 VDC. Not bad.

 

[Grinhill]

Wow, this is a very interesting project.

Well done. I don't think I've ever seen so much electronics on such a small vehicle before.

Sorry if I missed it, but what range would you expect to get with just the 35Ah battery and normal pedalling, no generator?

 

[JEB]

Good looking build, great photos, I did not see a total curb weight posted.

 

[AussieJester]

Congrats on being the first to actually get an AC bike running You are
a pioneer! However....

I don't see the advantages over using a brushless dc motor though sorry? they are simple to setup
all plug and play and only weigh a few pounds, They maybe more technical if you start pulling controllers
apart granted but 99% of the people wont be pulling controllers apart to "see what makes them tick" or
to "improve them" ...that ac motor @ 50lbs weighs nearly (or more even?) than some brushless DC setups.
I honestly can't see it being popular like Safe appears to think it will be ;-S The other alternatives
are lighter, smaller, powerful, NOT 240v and look alot less complicated to setup...

Best of luck with it anywayz... Least you actualy went out and DID it rather than talking about it for
8 pages telling us all how it could be done :-S Are you planning a "cross country" type trip are you?
Hope we get some video along the way of that...maybe a video journal of your 'adventure' even?
Are you working on a new trailer for the generator now? ETA on the finished setup?

KiM

 

[kentlim26]

Impressive, vey impressive build!!
great...thank u for a nice build photos for sharing.

if you have one day get a lifepo4 battery, that one can go for super range.

Cheers!!

kentlim26

 

[MitchJi]

Hi,
Nice clean job!

And it was ready to accept heavier-duty ANSI 40 roller chain, which has the same half inch pitch (link spacing) as normal bike chain, but is wider.

Why run heavier-duty 40 chain between the pedals and the alternator if it's only being driven by the pedals :??

 

[AussieJester]

Why run heavier-duty 40 chain between the pedals and the alternator if it's only being driven by the pedals :??

I'm guessing there wasn't an "off the shelf" sprocket suitable for a bicyle chain to fit the alternators rather large O.D shaft? Looks like something a ICE Go-kart would use?

KiM

 

[JCG]

Thanks all - let me see if I can get a couple of these questions!

- Grinhill: during my hallway/parking lot runs the inverter likes to draw around 18 A from the battery on flat ground up to some pretty fast speeds. I'm going to try and do track tests today or this weekend to get a power vs. speed relation, but for now I'd conservatively say that it would draw (on flat ground) around 25 A (300 W @ 12 V) from the batteries to cruise at 25 mph, the 35 Ah battery would last around 1 hr, 24 minutes (1.4 h) to take you 35 miles on the flat. Hills will shorten that up in the usual way. Again, just rough numbers there. I'll get some track tests to fit power to speed soon (get rolling, drag coeffs, etc.).

- JEB: A can get a curb weight by this afternoon with no trouble, I have a bulk scale in another lab. That'll be the first update most likely! It will definitely be an SUV of an ebike with that motor and AGM battery.

- KiM: The DC motors pack more punch in a smaller size/weight, it's true, though they have narrower application ranges. There's a lot of opinions, pros & cons out there, and ebikes are probably a little too small or light (and slow) to really scream for AC motors instead of DC. AC motors are more tolerant of abuse (especially thermal, since they don't have permanent magnets with Curie temperatures to worry about), though I won't be putting this one to too much stress. As you probably guessed, it was certain longer-term goals that pushed me towards the AC motor. If you want to take real advantage of them, you need plan to go at sustained high (motor) speeds. I like the easy ways to get regen from them, but there's no regen here and regen doesn't mean much on the straight and narrow long-distance ride. There is a Chicago-to-New Orleans trip being planned for four friends and I, with video documentation in the plan as well. It's set for next summer and will be for charity. Four upright bikes, and one recumbent electric trike that will let us recover from long-term upright riding once in a while. That whole thing got me going on this project as of the end of this summer! I'm not doing the bulk of the trip planning; let's hope it gets done... The trike is pretty much ready now except for tweaks. The generator-trailer won't take but a few hours to finish up (already mounted the hitch which you can see above the left-side rear wheel hub).

- kentlim26: Absolutely. a 12 V LiFePO4 battery would give me three times the energy per weight and more charge cycles. They unfortunately cost a bit much for me right now, and I don't have a proper charger either. I'm glad the SLA's are cheap, take a beating, and won't overcharge if I quit paying attention. I guess I'm also focused on the longer-term setup anyway (caps/generator, no batteries except for the CA).

- Mitch: KiM's right, it was originally off-the-shelf issues. I couldn't buy machinable sprockets easily that had the ability to use bicycle chain. ANSI 40 had the right pitch, so I tried using it on smaller existing sprockets (the original freewheel here at first, the original crank on my other bike). That got old and I had to do more machining than I expected for the freewheel hub (boring the sprocket to 2"), so I went ANSI 40 all the way. It's tough, not too heavy, and I have the right tool to break it and add/remove links!

Curb weight and other stuff coming soon. Thanks again all.

 

[fechter]

That's really impressive 8)

I don't imagine the range will be very good with a 35Ah lead battery though.
The charge controller for the pedal input will be unnecessary, but won't hurt.
I'm real interested in the AC motor controller you're using. I've seen similar units for cheap on eBay, some of them much larger in capacity. What is the rating of that one?

Ultimately it would be more efficient to avoid needing the 12v inverter and run a higher battery voltage. Curtis and Sevcon make AC induction controllers for 48v-72v. This would require a different motor or a rewind of the existing motor.

The other approach would be to run a very high battery voltage, like what you'd get off a used Toyota Prius battery. You could feed it directly to the VFAC drive. Most VFAC drives actually rectify the AC coming in, so they can run on DC as well. The only possible mod needed would be the low voltage power supply for the electronics would need to run on DC. If it uses a switching power supply for the low voltage, it could run off DC as well.

 

[AussieJester]

There is a Chicago-to-New Orleans trip being planned for four friends and I, with video documentation in the plan as well. It's set for next summer and will be for charity. Four upright bikes, and one recumbent electric trike that will let us recover from long-term upright riding once in a while. That whole thing got me going on this project as of the end of this summer!

Sincerely wish you all the best hope you raise a shitload of $$$ for charity and have an incident free trip. I very much look forward to viewing the video of the journey...Thanks for the detailed response also...Best of luck.

KiM

 

[JCG]

Thanks for the good wishes Jester. I hope that it works out.

The trike weight actually came in a bit less than what I was expecting. In all,

40 lb frame + 50 lb motor + 25 lb battery + 10 lb alternator + 32 lb other stuff = 157 lb curb weight (76 kg). Getting rid of that battery would be nice.

Fetcher, glad you found the thread. I have seen those lower voltage motors as well, very tempting (but pretty pricey too!). Most of the ones I've seen are well over 2000 USD. The motor I've got, being standard industrial-wound, only cost around 200 USD. But you're right, the inverter/controller combo is kind of weird and probably costs some efficiency.

The motor controller is awesome. I seriously love it. The reason is that it's so flexible. I bought it before I fully realized all of the things you can program it to do - not just overload currents and acceleration/deceleration profiles, but things like variable torque curves, frequency/voltage gains, frequency limits... all with intelligent input terminals that let you do things like my potentiometer to remotely control the frequency (not always a given for an industrial motor controller!).

This one is a 3 hp controller, rated for 10 A at 220 V (2.2 kW). But, I can overload it for acceleration up to 15 A for less than 1 minute at a time (3.3 kW). The power inverter doesn't enjoy that though.

Here's the user's manual. Enjoy.

Hitachi X200 Series

 

[rhitee05]

That is quite an impressive setup. Well done! Seems like you've found the right niche where an AC motor starts to make sense.

A little constructive criticism, if you don't mind:

You're probably not going to make it very far with that AGM battery, as heavy as it is. Running at ~1hp output (750W), you'll be pulling almost 2C (62.5A) out of the battery. Even with a high-quality AGM battery, you'd be lucky to get 1/2 rated capacity at that discharge rate. Even running at 25-30A as you posted, a little less than 1C, you'll see much less than rated capacity. Lead-acid batteries are typically rated at a C/20 draw!

I also suggest you reconsider your plan to replace the battery with nothing but an ultracap. 990F at 16V sounds like a lot, but that's actually only ~127kJ of energy (1/2*C*V^2) - which is enough to let you pull 750W for slightly less than 3 minutes. Actually, the voltage will be dropping that whole time so you won't even get than much out (~77kJ from 16V down to 10V). You could use the ultracap as a buffer to take the high-rate spikes off of the battery (good), but you'll still need chemical storage if you want to have any capacity to run w/o your generator, or to use more than it's rated output for any sustained period. If the generator is enough to cover your cruising draw, you could probably get away with a smaller battery if you're trying to cut weight. Or better yet, look into some of the Lithium options. It's more $$$, but a properly setup system with something like GGoodrum's BMS would be able to regulate charging and discharging as the power draw varies so it should still be mostly plug-and-play. You wouldn't necessarily need huge capacity, either, so that brings the cost way down.

Plus about a million to fechter's suggestion about getting rid of your inverter. Can your motor/controller handle 120V operation? You could reach that sort of voltage with LiPo or LiFePO4 without doing anything extremely crazy and just run the DC bus straight into the controller. Even at 90% per stage, when you're converting power through multiple stages that adds up fast (0.9*0.9*0.9...). Running DC directly to the controller would remove two stages, since the controller internally rectifies to DC then re-inverts to AC (the data sheet you posted shows this). Getting 220VDC would be trickier, but still doable. Running a high-voltage DC bus has the added advantage of lower currents, thus lower losses and thinner wires needed. The Prius battery is a great idea. You could run a small DC-DC converter to power a 12V bus for all your misc electronics.

Overall, great project. A really nice starting point if you're interested in experimenting to see just how much you can optimize it!

 

[JCG]

Good point, rhitee. The discharge rate of 1C might cut capacity to about half of its rated amp hours, that's true. Still, the battery is truly temporary - just there to help me answer that bigger question of how much current is drawn for cruising. With that number in hand, I can toss the AGM and go with the caps. The caps won't ever be used solo, rather only in series with the generator. This particular generator has load matching capability (speeding/slowing revs until load wattage is matched), so I'll take advantage of that by making sure there is just enough ultracap capacity on hand to handle surge (acceleration from stop or from one speed to another) power draw. For the series hybrid, the general design strategy is:

Average power draw: used to size primary (high energy) source (generator)
Expected: ~250 W continuous [charger can deliver up to 30 A at 12 VDC = 360 W]
Peak power draw: used to size secondary (high power) source (ultracap)
Expected: 1500 W for up to 30 s = 45 kJ [990 F caps discharging from 14.5 to 10.5 V yields 49.5 kJ]

So I'll still have chemical storage for range, that is, in the liquid fuel. I fully expect that cruising at 25 mph on flat ground will require far less than 1 hp. Imagine how easy it is to pedal your bike, even if it's a heavy one, along a flat straightaway once it's already up to speed. For example, even a Hummer needs only around 25 hp to cruise at 55 mph at zero grade. Unfortunately, its engine still has to be sized for peak power, and it's that number which dominates the design (say, 400 hp). If the trike follows an acceleration profile that needs around 1500 W for 10 seconds, 15 kJ will do the trick - 50 kJ is overkill.

My old hub motor bike required only about 250 W to cruise on the flat at about 20 mph, and I would be astonished if the trike used more than that considering its superior aerodynamic profile. But, we'll see. I'll try a few cruising tests this weekend (maybe Saturday night) and will get some current vs. speed data.

I have powered one of these types of motor controllers from DC before. Another nice feature of Hitachi controllers is that thave easy access to the DC bus for connecting braking units. I have supplied high voltage DC to these drives and it works quite well, even allowing for regeneration without any special unit, provided your DC source can soak energy up as well as providing it:

Separate ES Thread

The problem is that you need at least 190 VDC for this particular controller or the undervoltage alarm trips, turning the motor off. At any rate, that's lot of batteries - and not to mention scary. You'll need a larger platform than a bike to carry that many batteries and still have a decent amount of total Wh. Your idea is a great one for the car, however. That thing will have 390 VDC storage when the time comes.

Anyway, good stuff. Love the discussion.

 

[rhitee05]

You're exactly right about the cruising power draw, your generator will easily handle that at zero grade. But what about hills? I think there's a calculator around here somewhere, but your power draw increases rapidly if you're climbing even a fairly modest grade. That's the situation you'd want some battery-based storage for, to allow you 15 or 30 minutes' worth of extra power. Say you wanted to be able to sustain 1500W for 20 minutes. If your generator provides 900W, that leaves 600W (50A at 12V) to come from somewhere else. To sustain that for 20 minutes would require about 17Ah of battery capacity (conveniently, pretty close to what that AGM would probably give you). Even the crazy-powerful setups around here only use a fraction of their potential output cruising, the extra power allows for acceleration and climbing. Batteries allow you to reach your peak power output and sustain it for more than mere seconds.

Also, BTW, I was just reading again. You said your generator can provide 30A at 13.5V - that's only ~400W. Assuming you didn't mis-type there, that's not much power for anything besides cruising at zero slope. Even the tiny 200W road-legal setups from Down Under can draw upwards of 500-600W climbing. I'd hate for you to get into a situation on the road where the generator just isn't enough to make you go.

It would take a fair number of batteries to do a high-voltage DC bus, but not as much as you might think. I'll just use LiPo as an example, since it's what I'm most familiar with (see all the various warnings and cautions elsewhere). A 55-cell series of LiPo would get you 231V fully charged and 209V nominal. That's 11 of the standard 5s packs people like to buy, which are 5Ah each. Those packs aren't all that big or heavy (less than 1kg each), and people run setups like 16s4p (64 cells) all the time on their bikes. Even though it's only 5Ah, it's super high voltage, so you've got about 1kWh instead of about 250Wh usable in that AGM (12V*20Ah). All that for about the same weight and size of the current AGM. Harder than just using 12V batteries? Definitely! But you'd probably see much better performance. High peak currents wouldn't be a problem anymore, either - those LiPos are rated for 20C. 100A @ 230V would melt your entire bike!

 

[liveforphysics]

I work with VFD's as part of my job. Until you step up to a flux-vectoring VFD, they are just "dumb drives". If you set the slew rate to ramp frequency faster than your loaded motor can increase RPM, then they slip phase, pull a ton of current while efficiency drops very low. They work pretty decent for pumps and fans. You get zero timing control, and the performance is at the mercy of how smoothly you ramp the signal to change RPM (or limit the slew rate). If you don't like sensors, even an RC sensorless controller could run the motor with active reading of BEMF to know how to correctly set timing advance, and to slow the frequency if it slips a phase.

That conversion from pedal energy to useful mechanical energy is quite an adventure in energy state change.

Here is a tip for an extra few percent efficiency. The VFD runs the input AC power through a full wave bridge with a cap bank and switches from that DC source to the coil to generate the voltage that the H-bridge switches from to create the drive output. In other words, it would rather see DC input. Your inverter would rather skip it's simulating AC output stage and output DC. If you connect your leads from the DC rail of the inverter to the input of the VFD, you get to skip a lot of electrical fooling around.

350wh's of energy and 1500w of power. In RC equipment, all the parts would easily fit in 1 hand, weigh under 10lbs, and have loads better efficiency (and performance from the weight savings). I have a feeling you just wanted to be original in you design, and I congratulate you on that.

 

[recumpence]

I agree this is very overkill and very complicated to do a relatively simple job. That being said, I love the series hybrid concept. I have been kicking it around for quite some time. The big drawback is conversion of pedal power to electrical power, then back to mechanical drive power. That is the primary drawback to human/electric series hybrid. There is just too much loss there to make it worthwhile. Still, I am very impressed with how well you implemented this. There has been precious little research into series hybrid (human to electric) vehicles and, in that manor, this is a great build.

I love to see such a project come to completion.

Thumbs up.

Matt

 

[paultrafalgar]

I've quoted this before, but I think you need to read this from:
http://www.hupi.org/HPeJ/0015/0015.html

Efficiency

The SH drive system does not compare with a purely mechanical chain drive e.g. of a racing bike but was not made to replace such drives, but rather to replace mechanically complex hybrid drive systems.

The first working models of the SH drive were equipped with brushed generators with peak efficiencies of between 55 and 70% and with brushed motors with about 80% peak efficiency. However we were astonished that we rode about as long and far as typical PH e-bikes. This was confirmed when Chapelle and collegues measured efficiencies of PH e-bikes of between 55% and 95%. Thus it is possible to build SH vehicles with better efficiencies than the poorer PH bikes.

So far we only discussed “peak” efficiency. If the average efficiency during the whole trip is considered, the efficiency of SHs compared to that of PHs starts to look interesting.
In urban traffic a vehicle is on constant speed only for a minor part of the travel time. Therefore the advantage of high peak efficiency at one operating point of a parallel PH remains advantageous only if the efficiency at other operating points is also good and/or if the gears are used effectively to stay in the optimal region.

People not trained in optimal operation of traditional bicycle gears often pedal off their peak efficiency because humans have a quite narrow peak of high efficiency at some power levels.
A major advantage of the SH is that the system can react more quickly than mechanical gears. The efficiency of the system can be maximized electronically at every moment. The human being can be optimally loaded: the "load-leveling" capability of SH's is very advantageous from a physiological point of view. This was borne out by the author and colleagues and by Daniel Couque (who constantly pedals a generator while manually operating the throttle of the electric motor of his velomobile). The experiences are too few to draw final conclusions yet, but it cannot be easily discounted that the physiological advantages of a SH could over-compensate the disadvantage of peak efficiency of a SH compared to a PH.

 

[317537]

Although you put a lot of parts to make her work its all placed and spaced idealy. I like these projects that just come together out of most things one has at hand.

 

[JCG]

Thanks all for checking in. I need to send a personal message or two to ask some specific questions now. But, here's the reward for reading... Saturday after our football game my friend David and I took the trike down to the running track across the street from my office and ran it for a few miles. I need to tighten up the tensioner a bit but everything else worked better than I thought it might. One hilarious thing was that the GPS kept telling you to turn, the wrong way, as you went around the track. "Turn right, then turn right..."

Most importantly: the motor drew only 17-19 A from the battery (say, 12.5 V) for a power draw of around 210 - 240 W in the vicinity of full speed.

Dave was impressed. Ah, that e-bike grin.

Here's one of his passes around the curves.

[youtube]VVs9a0sMQpE[/youtube]

 

[recumpence]

Please understand, I was not trying to criticize your build in my post. I am all for this project. I merely posted the promary reason more series hybrids have not been built. That aside, I love it! For its weight, it sure seems to be efficient!

Matt

 

[JCG]

Please understand, I was not trying to criticize your build in my post. I am all for this project. I merely posted the promary reason more series hybrids have not been built. That aside, I love it! For its weight, it sure seems to be efficient!

Matt

Matt - you have nothing to apologize for... you're one of the good ones anyway! At any rate, I need all comments... or else I can't learn from others' experience. More than anything I appreciate the interest - it's what makes this fun! Thanks for posting, I'll try to keep updating.

 

[paultrafalgar]

I KNOW that you're doing this as a transition to an "electric car" project, but I still have to stamp my foot and trow a tantrum about it being TOO HEAVY! 50LB MOTOR! 2 HP! It would be SO INTERESTING to do it with an Agni motor and Lithium batteries!
There I said it

 

[JCG]

I KNOW that you're doing this as a transition to an "electric car" project, but I still have to stamp my foot and trow a tantrum about it being TOO HEAVY! 50LB MOTOR! 2 HP! It would be SO INTERESTING to do it with an Agni motor and Lithium batteries!
There I said it

:lol: Thanks Paul - I can always count on you!

Cheers
Jason

 

[grindz145]

Wow that's an incredible project. It would be awesome if you passed through western new york on your journey (Im sure not likely) but I would love to see it! It would be cool to see mods to increase the efficiency of the whole system

 

[JCG]

Thanks Grindz,

Though New York state might be a bit out of the way , if you find yourself in the Washington DC area before next August, come on over for a look. As for the mods, one thing a project like this shows you is what you'd do if you had a million dollars and could design from the ground up:

- custom wound motor (lower rpm, higher torque, lower voltage)
- water-cooled motor to reduce total weight
- vector controller with built-in regen

One mod to work on starting this afternoon - replacing the concept of the battery charger (350 W max, inconsistent control) with a 645 W current-controlled device (fixed 15 V, 43 A max) to feed the caps. Should make the long hills less of a problem! Thanks for getting me moving on that, rhitee...