# 1st EV build, any input welcome



## acornstu (Jun 3, 2008)

I've got a headache from all of the math the last few days. Been weighing the pros and cons of lithium vs lead and all that jazz. And feel free to point me to a newbie thread that may answer some of this but I can't really decide what all I need for my setup, and I figured there's no one better to ask than people who have already done this.

Basically I live about a mile outside of a small town (on top of a pretty steep hill )
obviously the longer range the better. But, bottom line i really need at least 5-10 miles on a single charge in average city driving conditions.

I'm a pretty large fella tipping the scales at just under 250 lbs.

I've come accross a few donar bikes and I believe I can pull off any wiring I need to so a kit would be a waste of money (at least the few I found on ebay)

Since I need plenty of power and would prefer not to pedal (yaya i know, i need to, just don't want to be forced to do it) i'm leaning towards a 48v 1000watt hub motor or better for the front and some lead batteries to cut on the cost.

Really i'm looking for a parts list. Just a rough guess to get me started. or at least a good site or two for cheap and dependable ev bike parts. 

I feel pretty confident that i could build a li-ion pack for my needs. But, in the off chance i screw up i'm stuck without batteries for a while. the initial cost of lithium chargers and premade packs is a little steep (but a link to some would still be very much appreciated) So, if i can get away with massive sla's then it's game on... I think










... and i just found the parts and distributors thread. it's late, i get a little ahead of myself when i'm this tired


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## Amberwolf (May 29, 2009)

With a big hill to always have to deal with, don't use a hub motor or any other direct drive system. Direct drive is great for long flat runs with no stops, but it takes more power (as far as I can determine) to startup from a stop or to run at slow speeds, especially with a load on the motor like you would have with that hill.

Use a motor that drives your bike's existing gearing, so you can take advantage of that, and set it up so that the highest gears get you at most whatever the legal speed limit is for ebikes where you live (it's 20MPH in AZ). 

You may need a double-reduction for the motor, like I have on mine at http://evalbum.net/2961 where it has a gearbox reducing the fast motor speed to around 120RPM. There's a new motor and gearing (not shown on that page yet) that's 135RPM output from the gearbox, with the chainrings setup from it to the drivetrain input that give it around 100RPM max. Better torque, lower speed, for startup and hill climbing. 

I originally had a planned setup (before I was given the powerchair motors/gearboxes) using a treadmill motor at around 3000RPM, which would have used a 3:1 reduction with it's original belt drive that then drove a 10:1 scooter chainring reduction to get me down to around 100RPM. That would have been the input to the regular bike drivetrain, where the pedals also input to, as they do now. I still want to try that out, as I never road tested it (just bench tested, where it worked fine). 

Then you can get much better range out of it with smaller batteries, otherwise with the hub motor you will be pulling much more current out of it at low speeds trying to go up that hill. 

You may also want to gear the bike lower within it's regular drivetrain, by using smaller front sprockets (it's usually harder to get bigger rear ones than smaller front ones).

If you use a trike instead of a bike, you can gear down as low as you want, because you don't have to balance it, so you can go as slow as you like up the hill.  My next one is planned this way for this reason, primarily because I often have to go pretty slow, and there are lots of traffic stops and slowdowns, and with the SLA batteries I have to use I can barely balance the bike at anything below about 8-9MPH. Starting it from a stop without the motor (even when motor and batteries are not mounted on it) is very difficult for me (due to bad knees, mostly). 


One catch with running the motor thru your bike's drivetrain is that it will not be able to do regen, because of the freewheel in the rear wheel's cassette or hub. You can disable the freewheel, but then you cannot coast, and would have to always pedal or run the motor or both. 


Note that 90-100RPM is an average speed for the input to any bike's drivetrain at the pedals; if you typically pedal a lot slower than that, then calculate your motor's output gearing to give you whatever your regular pedalling cadence is.


If you really want to do it with regular hub motors and such, you probably can, but I don't have any idea which ones are good, and which to avoid. 

You might also want to check out your locality's laws on sizes of motors allowed and such, as some don't allow motors that big on ebikes (1HP is a limit I've seen used before, which is ~750W). 

Disc brakes would be a safe addition to whatever bike you use, because going down that hill with the extra weight of the motor and batteries (especially if you use 48V SLA) is going to be a potential adventure every time if you don't. 

Even on a flat, at 15MPH, with my 120pound bike and 150 pound self, stopping suddenly is quite a challenge. It's only got a front rim brake right now, but even with rear rim brakes added it would still not stop fast enough, and the wear is quite significant. I want to use disc brakes but until I can find a free or extremely cheap donor bike with some, they're out of the picture. 


For lithium batteries, I'd check with Dave at EVComponents; they seem to be the cheapest I know of, since they are essentially doing huge group buys every few weeks or so. 

Other than that, one of the most well-known of the small ebike battery makers with a good reputation is Ping Battery on ebay. I have not bought anything from any of them yet, but in all the reading I've done in the last couple of years, the best batteries for the best reputation (not the cheapest, though!) is Ping.
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## acornstu (Jun 3, 2008)

hmm, well thanks a lot. i've got some more to consider it seems. and for your disk brake problem i'd keep an eye out for a donar bike as you are, but also for any junk scooters kids have tossed. that's where i got my front disk brake and with a little work i think it should fit my bike nicely. as it turns out my budget is going to be around $400 give or take. I'm probly going to have to go over a little to get the power i need. speed isn't to much of a problem, nor the laws around here. i live in BFE 50miles from the nearest person with an ebike or more. so most likely i'll get by with it for a month before the cops get upset and make me park it or tag it. i really doubt i'll get a ticket since i know a lot of them but, you never know. in the mean time i'm trying to figure out all this b.s. for making your own vin numbers and getting it tagged as a motorcycle. i've considered building a trike or finding one cheap, but i'll probly start with the two wheels so i can take the sidewalks and hide from 5.0


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## ithinkidontknow (May 14, 2009)

Amberwolf said:


> Use a motor that drives your bike's existing gearing, so you can take advantage of that, and set it up so that the highest gears get you at most whatever the legal speed limit is for ebikes where you live (it's 20MPH in AZ).


In researching for my project, I found that in some states it is actually illegal to have a variable gear drive for electric bicycles or mopeds. This is the case in Washington. Even if you don't go over 20mph (or 30 for mopeds), they still want it to be direct drive to the wheel. I don't really know the reasoning behind this, it may be because they are worried about people having bikes with potential to go way too fast but I couldn't really say for sure. 

Anyway, I would say look into the laws a bit more before putting something together that you can't drive legally. Best of luck though!


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## acornstu (Jun 3, 2008)

that's strange. thanks for the warning. i'm sure someone will pull me over and make me parked the damn thing


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## Amberwolf (May 29, 2009)

That's definitely strange, and not something I'd ever heard of. I won't bother asking the rhetorical question of "why?" because when legal matters come up there is often enough not a good logical reason, and trying to figure it out makes my head explode. 

Do you have a list of states that include such laws? Or is there a site out there that already lists them that I have not yet run across? I'd like to put it up as a warning on my Electricle blog in my links section if there is, so that people in those states don't try to do what I am currently doing here in AZ (where I am unaware of any laws against such a thing, and I've done quite a bit of research on motor-assisted bicycles for my area!).
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## ithinkidontknow (May 14, 2009)

I just stumbled across it in the Seattle municipal code when I was trying to read as much as possible about mopeds and electrically assisted bicycles. However, I can't find it again!  

I will keep looking because it may have been in the Washington code or something but I swear that I read that which is why I ended up deciding on a single gear drive. So for now, take my words with a grain of salt because I could have dreamt the whole thing up.


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## acornstu (Jun 3, 2008)

yeah, i've just got a pretty good idea that even though most of the cops in town are cool that i'm going to get told to park it because it's a "motor vehicle"


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## ithinkidontknow (May 14, 2009)

Here are quick summaries of whatever the laws are where you live. http://en.wikipedia.org/wiki/Electric_bicycle_laws
Hopefully this will tell you something. As long as you stay educated on the rules, you shouldn't have any issues with cops.


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## acornstu (Jun 3, 2008)

well thanks for that . i've done a little more research too and found nothing on kansas. but, from what i've read they let the city decide wtf they want, and all it will take is one cop on a bad day to tell me to park it. and if i decide to fight they'll just change the city regulations before i even get to court so it won't matter. not trying to be mr. negativity here but i'd hate to build the thing and not be able to use it. i guess i'll just have to go and ask all the cops in town if they have a problem with it before i start working on it. who knows, i might just pawn my jeep and build a motorcycle if they push me to far


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## elevatorguy (Jul 26, 2007)

I know most states limit you to about 20 mph for an assisted bicycle, that is what I found in my state.
The bike I build did 27 and had range of 20 miles at 20 mph, I think your requirements could be met although I don't know how big of a hill you have to deal with.
I used 18 AH batteries at 36 volts. I left the pedals and chain on so it would be a assisted bike, but rarely used them.


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## acornstu (Jun 3, 2008)

even though i was persuaded to do without the in hub motor, i may still decide on that. i'll be using a 48v 1000 watt front wheel motor. i found some 10ah batteries and will try it with that. if need be i'll purchase an additional rear hub 48v 1000 watt motor and more batteries. even though it will be pretty heavy if 2000 watts of motor can't haul my big but then i need to pedal and drop a few anyway. plus i don't really need to go over 20-30mph anyway so i'll play with the gearing until i'm happy.

thanks for the help guys


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## Amberwolf (May 29, 2009)

And if you do later choose to do a geared motor drivetrain, you can still use a hub motor to drive it, it just gets more complicated since you're rotating the body of the motor while holding the shaft in place.  But it means you could mount the gear (or belt) on the casing instead of the shaft.
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## acornstu (Jun 3, 2008)

i recently found a 2000-3000 watt in hub motorcycle motor, wheel, and tire for about twice what the 1000watt in hub bicycle motor would cost. i believe this is my best bet as i can just toss it on the front forks (i have an old dirtbike front end.) i'll still have pedal control and later perhaps an electric motorcycle


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## Amberwolf (May 29, 2009)

I suggest that you beef up the fork's dropouts, though, if it's a regular bicycle. If they are aluminum, replace them with good steel. 

I've occasionally heard of even just 1000W (or less) front hub motors tearing out of forks before, so I can only imagine what might happen with something that's twice (or more) that power. 
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## acornstu (Jun 3, 2008)

oh no, lol i heard that also. i'll be using the front fork assembly from an old dirt bike (i believe it was a 250cc bike.) and although it's a little heavy i think it'll be safe. i've been down before and the last thing i want is the front end exploding. thanks for the help guys. i'll let you know how it turns out in a few weeks


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## Amberwolf (May 29, 2009)

Ah, I see you said that before, but I somehow missed that about the fork. 
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## john818 (Aug 1, 2008)

acornstu said:


> not trying to be mr. negativity here but i'd hate to build the thing and not be able to use it. i guess i'll just have to go and ask all the cops in town if they have a problem with it before i start working on it. who knows, i might just pawn my jeep and build a motorcycle if they push me to far


Asking cops might be a good idea, but you should probably check with your local DMV too. They should have a better idea of what's legal and what's not.



acornstu said:


> even though i was persuaded to do without the in hub motor, i may still decide on that. i'll be using a 48v 1000 watt front wheel motor. i found some 10ah batteries and will try it with that. if need be i'll purchase an additional rear hub 48v 1000 watt motor and more batteries. even though it will be pretty heavy if 2000 watts of motor can't haul my big but then i need to pedal and drop a few anyway. plus i don't really need to go over 20-30mph anyway so i'll play with the gearing until i'm happy.


My 2 cents: Rather than going with two hub motors, I'd do a motorcycle. It's going to have better brakes and a strong enough frame to handle the power and weight. 48V x 2 is going to be pretty heavy with decent Amp-Hours, and I might be wrong here, but controlling the two motors might be more complicated than it sounds.


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## Dink (Jun 3, 2010)

The police are no help. State Patrol maybe. They just enforce not make laws/codes. Check the revised code for your state. I found them online, on state gov sites.


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