# Planning my ultimate summer car



## ausgolfer (Aug 1, 2008)

Hi everyone. Am relatively new here(few days old) and this is my first post(been busy reading and learning).

*Anyway a bit of background:* I am a mechanical engineer, with decent hands on skills, but I am the first to admit I know bugger all about electronics and electric motors.

*The vehicle:* well this is going to be a long term project, what I have is a meyers manx body shell. Am not using a beetle floorpan as usual. But am going to fabricate my own chassis and suspension which I have designed already. Just haven't built. Here are some pictures of the very little I have at the moment. I am intending this to be used on the road and street legal.

























Anyway have been wanting to build an EV for quite a few years and thought why not this car.

Ok so obviously I have a few ideas of my own(which may be way off target) but *am very open to thoughts/interpretation and suggestions.*

*My ideas:*

*Batteries and Controller:* No idea am learning.... But what I do know is I could mount a few batteries up front under the fiberglass hood between the suspension arms. And quite a few more above the proposed motor in the rear, under where the rear seats would be.

*Drive:* What I would like to do is use one or maybe even 2 motors coupled directly to a conventional differential in the rear. Possibly in the configuration of one motor either side and just forward of the diferential with the coupling facing towards the centerline of the vehicle. Should really draw a diagram....

*Weight:* Well I'd like to make it around 750kg(1650lbs) total or less. Considering an original meyers manx weighs in at about 450kg leaves a lot of room for batteries. Also the lack of a gearbox would help in the weight department.

*Performance:* Don't laugh just yet...I would like something quick.... I know it'd cost but I can worry about that later once the chassis is built. If it could be something similar to that "aerial atom EV" (think it was an aerial atom in the you tube clip) Given the low weight of the vehicle it might be possible. 

*Range: *Would like it to do 100kms(62miles)maybe more. Again the low weight, I hope, would contribute to greater mileage, and not like one would be accelerating to maximum speed all the time.

*Other ideas: *Am thinking a small diesel powered generator mounted above the batteries at the back could get me out of trouble at times. If one was planning a long trip once they arrived they could set the motor using a turbo timer and have a partial charge by the time they return to the vehicle for the return trip that or just borrow an extension lead.

What are surge magnetic motors? are they worth looking into?

Read a little about the variable brush timing rings a member is producing might be beneficial to performance and mileage??

Is it wise to have no gearbox meaning when reverse is needed one has to reverse the electric motor/motors? is that a problem? Also a lack of gearing could be an issue but if 2 motors were used combined with low weight might be less of an issue??

Anyway I'll stop with this essay and would love to hear your thoughts and ideas.


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## skullbearer (Jul 9, 2008)

Well, a couple things.

Batteries: Gonna have to go lithium probably to get the range and performance you want.


Drive: Considering your target weight, two smaller DC motors run individually to each wheel would eliminate your diff completely and give you the same power, and you still would only need one controller.

See this thread about that.


Weight: The motors are probably going to be about 60-120lbs depending on the power and model... your controllers and other equipment according to the generic numbers I've seen will run you another hundred lbs or more. That all said, that's A LOT OF BATTERIES for your target weight.


Performance: Lots of batteries = lots of performance, or lots of range, or something in between. You're not drag racing in 1/4mile increments, so I'm suspecting you want something inbetween.

This will probably be in a 96V/120V setup with the motors in parallel for max torque (assuming you have the two motors) and then 192V/240V with them in series for max rpm and speed, since you aren't going to have a gearbox.


Range: You might find your range is significantly more given the amount of batteries you can hold, if you go with good lithiums.  That or your performance is significantly more... hehe.


If you're going to lug a diesal gen around with you, you might look at setting the vehicle up as a semi-hybrid... or so I call them. Have the generator automatically started whenever your DOD reaches a certain point, or at the press of a button to extend your range further. If the generator can produce even just half of your cruising power needs, you can nearly double your range, or charge the batteries in just twice the time you used to expend them (at cruise). If you match your cruise requirements, you could concievably run it as a series-hyrbrid, in which the motor provides direct power and the batts are charged on any extra, or discharge for any additional needs.


Anyone thought about combining a diesal-hyrbrid with solar? You could have a smaller generator and you might not even need it most of the time.


Let me dig up some links here... darn, sorry, someone was supposed to have sent me a bunch of links to some solar cell companies that made good solid modular cells for satellites that are about 3x4inch modular pieces at about $4 per watt for 20% efficient, and $8 per watt for nearly 30% efficient ones.

The 30% make (they claim) about 320W per square meter in bright daylight. You buy them, piece them together (they actually connect together and are semi-flexible, and you end up with a + and - connection at any corner), and then put on a special super-clear coat so they are weatherprotected but still work fine. Were designed originally for satellites, but I can't find the two companies we were looking at via google atm.


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## JAFO (Aug 2, 2008)

skullbearer said:


> This will probably be in a 96V/120V setup with the motors in parallel for max torque (assuming you have the two motors) and then 192V/240V with them in series for max rpm and speed, since you aren't going to have a gearbox.


*So, you can setup several banks in series, then place them in parallel ?*



skullbearer said:


> Let me dig up some links here... darn, sorry, someone was supposed to have sent me a bunch of links to some solar cell companies that made good solid modular cells for satellites that are about 3x4inch modular pieces at about $4 per watt for 20% efficient, and $8 per watt for nearly 30% efficient ones.
> 
> The 30% make (they claim) about 320W per square meter in bright daylight. You buy them, piece them together (they actually connect together and are semi-flexible, and you end up with a + and - connection at any corner), and then put on a special super-clear coat so they are weatherprotected but still work fine. Were designed originally for satellites, but I can't find the two companies we were looking at via google atm.


I would love that link for these, have the idea for range extension via solar
since I live in Arizona, w/ 360 days of SUNSHINE...


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## TX_Dj (Jul 25, 2008)

ausgolfer said:


> What are surge magnetic motors? are they worth looking into?


All I've seen about this "surge" crap that you find on youtube posted under the guise of "electric vehicle technology" is a perpetual motion scam, some nut-brained kook who believes the laws of physics don't apply to him.

I've seen his video on youtube, and it's quite apparent to me that he has no clue what he's talking about. He can't even explain the components in his "surge-powered vehicle" which everything he points to are basic electric vehicle conversion parts that any converter should know how to explain properly. He also claims there are no batteries in that car, but never proves it... 

My money is on batteries for the win, over-unity for the fail..


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## ausgolfer (Aug 1, 2008)

Thanks *Skull* great ideas.
I had thought of the motor per wheel thing but was unsure that it'd be too much unsprung weight?? 

Am keen on the small generator and Solar cells on say a cuved roof(well something more modern than the fiberglass square roofs you see on some manxs, am thinking two big curved roll bars running from a virtual a pillar to the rear strut towers). But think I'd avoid coupling the diesel motor directly to the wheels. And would still be happier to plug in the vehicle to charge overnight, and have the diesel motor purely in emergency situations.

And like *Jafo* said bring on the liks 

Thanks for the clarification *TX_Dj* about the surge motor, thought as much, you just can't get something from nothing, but always safee to ask a stupid question when you're new ha ha.

I was reading the* plasma boy racing* site last night and noticed that the "blue meanie" had similar but slightly less perfromance and range to what I would hope for, and it was using AGM batteries. Since my vehicle would be lighter I suppose with a simiar set up I could increase performance and range.
Am still unsure of all the pro's/cons of these AGM batteries(still learning), but they look similar to the oddessy batteries sold down here. Which are about $400 AUD a pop and say one used 12 thats nearly 5K for batteries which seems reasonable compared to some that I've read on here...

I also read that the "white zombie" now uses a 25kWh lithium ion pack although they don't mention any sort of range. Does any one have any info on the approximate cost and range at least for comparison on these? Also what configuration do they come in? the only large Lithium ion pack I can think of are those in small Electric pushies(which seem to be a long thin rectangular shape).

Anyway am off to read the bit about "in wheel motors" 

Thanks again for all the input looking forward to more.


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## ausgolfer (Aug 1, 2008)

In vehicles where you change from parallel to series is it done manually? Via a button or switch or is it done automatically via the controller?

I imagine driving a vehicle like this would feel like it was changing gears albeit somewhat smoother??


Maybe I could run 2 AC motors(low RPM is the idea I'm getting) in the middle of the vehicle facing the rear, side by side, each with a 90 degree drive on them to power each of the wheels via an driveshaft and CV joints to avoid unsprung weight.
It would eliminate the complexity/weight of the diff and two motors driving the same diff.

Good idea? bad idea? Am I getting way off track?


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## JAFO (Aug 2, 2008)

Correct me please if I am tracking wrong here:

Series and parallel are referencing the battery layout, right?

Some nice info is available in the FAQ here and this to:

http://www.usbattery.com/usb_config_6.html


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## joseph3354 (Apr 2, 2008)

as an engineer i am sure you are familiar with the KISS principle.multiple motors and such will complicate your build.maybe if you had a vw or audi transaxle for it you would be able to go with a straight DC conversion.less complex and less expensive.an AC conversion would work as well,but more complex ,more expense.you could acheive your range requirement with AGMs or lifepo. good luck with your project!


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## joseph3354 (Apr 2, 2008)

JAFO said:


> Correct me please if I am tracking wrong here:
> 
> Series and parallel are referencing the battery layout, right?
> 
> ...


i believe he is refering to the motors.running dual motors in parallel will produce more torque,then switching to series will provide higher rpms.


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## TX_Dj (Jul 25, 2008)

Yes. This is how the White Zombie works with John's "Siamese 8" motor combination. 

He uses the two motors in either parallel or series to provide either a higher torque or higher speed, and this works similar in effect to a 2-speed transmission. One configuration is used for the launch and first few hundred feet of the track, then the contactors switch and reconfigure the motors in the other configuration, giving the ability to wind out to maximum speed.

As for the question about the range of the Zombie, I don't know that answer. It is still technically a street legal car, but it is designed to stomp unsuspecting ICE drag racers who scoff at an electric as a slow vehicle. They can make several runs without recharging, but typically do top off the pack.

I don't know if he still is, but John used to be extremely active on the EVDL. If you ever get a chance, search the archives for his stories about his raccoon problems about a decade ago. John's stories are always a hoot to read.


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## skullbearer (Jul 9, 2008)

I shot an e-mail off to the guy who was supposed to send me those solar links originally. I was working with him and a couple others on a solar ev project to be funded through SMUD, but I had to leave the project when it was beginning to turn out I was going to be doing 90% of the actual design while fighting some younger guys 'cool' design ideas, such as putting a wind turbine on the vehicle in a port where air would be allowed to flow through and was reduced from its intake size so the air would be moving faster.


I don't know how many times I explained it would create more drag than it would produce energy to counteract. Anyway, they were bright guys just fixated, and I really hope they do well with the project.


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## ausgolfer (Aug 1, 2008)

Such a shame when some people just can't be told.

On the project front, have decided to take a short cut buy getting myself a cheap beetle cabriolet disposing of the body*(can avoid the need for engineering if it's already registered as a VW roadster/cabriolet)*, and applying my suspension design and additional torsional strength designs to the beetle floor pan.

Then I'll either use the beetle style gearbox or put something else in it's place.


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