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Discussion Starter · #1 ·
OK, here we go. I dont generally share my projects with the community, but I think I could use some input on this one.
I'm constructing a 2F1R electric trike with a minimum of donar parts, mostly axles/spindles and control arms from an 87 turbo coupe and wheels from a 2003 ford focus.
I've purchased a ImPulse 9" motor for the project...I have yet to receive it but hope to soon. The motor is a bit large, but i'm hoping to use a single stage reduction to the rear wheel, this may help me achieve that.
I have the front suspension components in hand...except the parts I need to make, I also have the chassis materials on hand, 2x4x.125" and 1x3x.125" rectangular steel tube.
I'm hoping to come in around 1500lbs, driver included, and have room for 12 cells of whatever. and i'd like to be able to drive 24 miles round trip at minimum.
anyhow, the design is still in process, but you can see a basic layout attached, and no, I dont have a body designed yet, but i want it to be totally open, more of a climb ON rather than a GET IN design.


Thoughts?
 

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A couple concerns.

1) Where do your feet go? I undertand the climb on rather than get in, but the seat is mounted pretty load to be above the batteries. Maybe it's just the forced perspective, but the seat looks really close to the back end of the batteries.

2) If you're using lead acids, which is what appears to be pictured, I think you're in trouble for weight. FLA run around 70ish pounds, meaning 12 is 840. That leaves you 660 lbs for everything else. Driver, motor, controller, etc. are going to take up a good 300. 360 for frame and tires sounds pretty optomistic, but I'm not super familiar with the actual frame weight, so I could be wrong.

3) holy #$%^#$ it floats!!! J/k.
 

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Discussion Starter · #3 ·
thanks for the comments rillip.
1. there will be foot platforms on the outside of each frame rail, you straddle the batteries
2.I was looking at exide golf cart bats, GC-145-6V for size and weight on them was 40+ lbs....think i'm headed the wrong direction already? I'm a bit confused by all the bat info out there..and in here for that matter, i'm definitely doing lead but am a little wishy washy on what to go with, so i settled on these dimensions. anyhow, you're probably right...but a guy can hope cant he?
3. LOLOL...yep thats my secret, no friction!!!! someone told me it was better that way....er something.
 

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Discussion Starter · #4 ·
oh and as it sits now, i get an estimate of 443lbs sans bats, motor and me, but the chasis isnt nearly complete yet.
 

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Ah, I didn't realize you were going for 6v batteries, those would be smaller than the 12v I was thinking of. 72 volts is a respectable size for such a light vehicle. Make sure you get high Ah batteries if you want to get any sort of range though - lower batteries means higher amp draw. You'll also need a higher rated controller.

But I think the weight and cost offset of the batteries is more than worth it for this weight. Many bikes that I've seen have used 48-72v systems so that seems pretty on track. That gives you 45 x 12 = 540lbs + 300 lbs of you and stuff, leaves about 660 lbs for the frame. That 300 lbs kind of depends on how big you are, but for something this light you won't need a big motor. Yhou should be really close to that 1500 mark, depending on the frame and your glutius maximus.

I used to want to make a traditional hovercraft because I thought (I was young!!) that with no wheels it must have almost no friction...

Edit: make sure you leave room for a 12v accessory battery if it's going to have any sort of radio/lights/fan (doubt you'll have wipers based on what you've said here). You can go with a little 12v motorcycle battery for this though and hook it up to a dc/dc converter, which is common. You won't need a deep cycle here, you won't be pulling high amps for these.
 

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Personally, I would like to see you with more than 72volts in that thing. 120volts or so would be sweet! If you only need to go 25 miles, you might as well get amazing performance for those miles. Plus, you might need that extra power in order to have a direct-drive system that works well.

By the way, what are your monetary restrictions for this project? If you don't mind the question.

Regardless, this seems like a great project. I am looking forward to hearing your progress! Make sure to keep us informed.
 

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Discussion Starter · #7 ·
hey guys,
thanks for the comments, i really appreciate them.
you know i once read somewhere that it wasnt what voltage or amperage you ran that gave you range, it was simply the amount of lead you had...so if i were to run 12v lower capacity bats it wouldnt be much different from running the same weight of high capacity lower volt cells....dont know how true it is, but I may end up going with a 144volt system....who knows, i'll see what lands in my lap.

as far as controller, i'm hoping to build an open source controller for it, should give me plenty of room for power.

funny you should bring up my glutimu maximus, its not real big, but i am...nearly 300 lbs of solid....well, not much solid..anyhow the 1500lbs is probably not going to do it...but i'll work with whatever i get, and there are some areas where i can lighten it up. I should have gone for 2x3x.125" for the main rails, but it to late for that now :)

as for financial restrictions, well, their fairly sever, and getting worse every day, I sold my truck to buy the motor. (i have another car) and I lost my job about 2 months ago....well, i know where its at, its not like i LOST it, but i let it go away. so whatever i can do on unemployment i guess. before i lost my severance pay i bought my chassis material and the car parts. even if i cant finish it for quite a while, i'll have plenty to work on.
 

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I don't know about the amount of lead you have being the range factor. However, it does make sense because more lead would decrease the amount of peukert losses you would have on a smaller set of batteries. For this reason, more batteries is going to give you more range not proportional to the amount of capacity they have. That said, it only makes sense that higher efficiency lead acids would carry you further. Another thing to think about is that from what I have seen, EV's generally become more efficient at higher voltages. 144v might not be unreasonable because you can run it at lower amps. With 12 lead acids of reasonable size you should be able to get your 25 mile range goals. Especially with the light chassis as you have.

So even if 1500 pounds isn't doable including the driver, that's fine. Just build everything except the driver as light as possible, then if you are having range issues you know that theres some weight that can be cut out of the glutes :D

Not having money might actually be sort of a blessing. This way you wont find yourself wasting money on unnecessary things. Plus, with all that free time you will be able to scrounge for used parts! As long as you have enough funding to barely get it done, it will get done, and it sounds like you do.

Anyway, best of luck for the next steps!
 

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Discussion Starter · #10 ·
Guts, yep thats why i read all through your post and studied your pics. :)

so, today i spent building a cheap layout table...well i dont have it done yet, but 3 more legs, fasten the top on and coat the top with something to keep it from absorbing water and warping. I'm making it out of wood, 2x6 framing, 4x6 legs, 6 of them....down from 9 :) and 2 layers of the flattest 3/4 ply money can buy...for 18 bucks a sheet. I've got levelers for all the legs, so hopefully it will be sturdy and steady enough to make a good fab table. heres the question.....i dont have any sheets of steel big enough to cover it, and i'll be welding on it...is there a waterproofer/sealant that will not burst into flames? I guess i'll go looking. i just dont want it to warp from a water leak, which the machine shed seems to have a few, but only when it rains... wonder why that is?

oh and i'm trying to get a rear axle made, sent a print off to moser to see if they could/would do it...havent heard back, otherwise i'm afraid i'll be making my own, which sounds dangerous. but i think i can, just barely, get the tbird axle mounter on centers in my lathe and grind bearing seats if i have to. raise your hand if this sounds like a bad idea...? anyone???
 

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Food for thought ....

The new (2008) Honda Goldwing swing arm I'm using I bought off Ebay for $225. It came with a new wheel and tire as well. I then sold the wheel and tire on Ebay for $185 because of the custom setup I wanted to run instead. The math worked out pretty well.

If you keep the wheel and tire, $225 for the whole deal is hard to beat - can't get much custom machining done for that price. New swing arms are available on Ebay all the time, Honda and others, because of conventional trike conversions being done.
 

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I got everything but the driveshaft, brand new, brake , wheel, tire, frame, for $119.00 on Ebay, last year. Need to find the Driveshaft and bearing and boot. Gold Wing 1800.
 

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Discussion Starter · #14 ·
yeah, i looked into that, end even did the hunt on ebay, but to be honest, i'm not really attracted to the idea, i'm sure they work fine, but i just dont care for them....sounds like a hell of a deal financially, for the arm anyhow. what did your wheel and adapter cost ya?
 

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yeah, i looked into that, end even did the hunt on ebay, but to be honest, i'm not really attracted to the idea, i'm sure they work fine, but i just dont care for them....sounds like a hell of a deal financially, for the arm anyhow. what did your wheel and adapter cost ya?

Had the adapter machined at a local shop for $125. I believe the custom offset wheel (16X8) was $150.

I went with the one sided swing arm because it allowed me to put the size tire on the back I thought would look right without going with a $$ widened swing arm. This required being very careful about the proper backspace for the wheel so it would work with the adapter and the swing arm and then offsetting the swing arm to the right to compensate for the wider tire, allowing the tire to track in the center line.

Yeah, I know this isn't the proper way to make tire decisions for EV's as that wider tire has a lot more rolling resistance, but there's a cool factor I had to figure in. A skinny rear tire on a street rod - themed vehicle just wouldn't be right! And since I'm not shooting for a lot of range or speed I figured it was an OK sacrifice to make.
 

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Discussion Starter · #16 ·
hey, rat rodding isnt about efficiency!

went and picked up my motor today!!! super excited, but it wont spin using a 12v 6 amp charger, so i figured i'd try a gel cell i have sitting around.. any thoughts?
 

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hey, rat rodding isnt about efficiency!

went and picked up my motor today!!! super excited, but it wont spin using a 12v 6 amp charger, so i figured i'd try a gel cell i have sitting around.. any thoughts?
Keep it at low volts until you have load on it, or it will spin to death. Without any load, there's very little self-limiting built in with the mottor and it will over-rev. But 12v won't do it any harm.
 

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Discussion Starter · #18 ·
yeah, i was keeping that in mind......didnt want to do ANYTHING to toast that motor, pretty much the last of my cash is in that motor ;).
anyhow, finally got it to spin, i wasnt sourcing enough amps for it to power up, tried a 12v gell cell, a little one, it still wouldnt run,but i could get a spark off of my clamp when i went to connect it. so i wired another matching cell in parallel with the first, and she spun right up, pretty thrilling for a first timer with no electric car experience :D...its the little things right? well little and expensive.
thanks!
 

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My wife is demanding my attention (shopping), so I have only scanned the comments so far, but I am in exactly the same position as you but a good bit further on. I have the drive system and completed chassis, most of my bodywork and plans for almost everything else including battery choice. Leave a message here for me and I will be happy to discuss things in tedious detail! Breifly 6*12V 110Ah batteries weighing 151.2Kg (335lbs) should give me a range of upto 40 miles. Aerodynamics count for a lot so consider some bodywork. Also why so much weight-kit cars are usually built using 1 inch square by 1 sixteenth box section and weigh more than 1500lbs including the engine. I'm using a ladder plus spaceframe superstructure using one inch with 50mm by 25mm by 3mm for the ladder-got to go now!

Cheers,

Duxuk.
 

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It sounds to me like the frame weight estimate is to high for this; I think you could have that frame down to between 150 - 200 lbs and be much closer to your target weight.

On battery voltage it mostly depends on how many RPM you are going to need out of your motor; amps = torque and volts = RPM. the other issue is Pukarts affect, ( I am probably not spelling that correctly) for the same watt hours in each pac a higher voltage lower amp pack will get beter range than a lower voltage higher amperage pac.

How fast do you want to go?
 
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