Its a large and confusing world. Help?

[jpullen88]

Hi,

A few years ago i looked into converting my old bike but it just looked to be too much hassle for too little. I think the problem was hub motors weren't readily available, it was not cost effective and the batteries were big, heavy and did not hold a lot of juice. Well it seems things have changed at least to a certain degree. I have tried searching myself and that is how i stumbled onto this forum. It seems you guys (gals too?) have been in the game for quite some time and have acquired a bit of knowledge about certain things.

So if you could reply an answer or give me some guidance i would really appreciate it.

you see, im on the fence about converting my 09 Giant Defy 2 roadie into electric or buy a new bike and convert that. The new bike would either be a 3 wheeled (2 in front) recumbent or a front/back shock mountain bike. Both new bikes would have disc brakes, as my road does not and stopping can already be problems when i hit over 20 mph.

my road bike is as follows
700c wheels, currently using a type of aero tire that is very narrow - is it possible to get a wider tire to accommodate the extra weight while still using the 700c rims?
bike alone weighs about 18-25 lb's
has v brakes
I have a rack/milk crate already and the rack is rated for 40 lbs i believe (definitely over 30)
bike has no shocks other than carbon fiber fork and seat post
I weigh around 155 lbs and am 6ft tall as it seems rider weight makes a huge difference in performance

The environment is gainesville, FL (go gators!) and this area is hilly for florida but overall pretty flat. Most hills go up 50 ft and then drop 50 ft shortly after.

This is what im looking for.
Speed of around 40-45 at the top end
Range of around 40-50 miles
acceleration needs only to be moderate
I will be pedaling

should i get a bike with shock absorption and possible wider/grippier wheels (like a typical hybrid bike or mountain bike) or would i do fine with my road bike?
I know you theoretically can get any amount of mileage you want, you just have to keep adding batteries (is this logic correct until diminishing returns kicks in?)

Thank you big big

 

[swbluto]

Unless your roads consist of race-track type of smoothness, you'll probably want to ditch the road bike. Above 30 mph, high-pressure "feel everything" tires on a bike can make handling dangerous on bumpy roads and higher speeds aggravate that trend. In that spirit, yes, you'll want wider tires but you'll also, more importantly, want suspension.

For 40-50 miles of "one way" range at 40-50 mph, you'll need approximately 40wh/mi. * 50 miles = 2 kwh. While not impossible, it's not going to be cheap. And if it is cheap, it's going to be prohibitively heavy (Think 100+ pounds of lead). Either way, you're looking to add a minimum of 30 more pounds to your bike. As far as battery cost for something other than lead, expect something around $1000 to $1750 dollars depending on what battery you get and where you buy it.

 

[TylerDurden]

This is light-motorcycle territory. A downhill bike might be strong enough, but the geometry might be skittish. A 'bent would be fodder for crazy Florida drivers (redundant term), they will never see you at those speeds.

I estimate more power and capacity are required, >2.5kW sustained, drawing from >3kWhr pack.

A pack that size will need to be some lithium chem to be light enough.

Fairings would be a good idea.

The build will not be easy or cheap.

 

[jpullen88]

ok so that doesnt sound like such a good idea, especially on the road bike. Would you recommend a MTB due to being easier to spot vs a bent? Also, the diy kits that i have seen online, what can i expect out of about $1000-$1500? I know this is a difficult question to answer. Is there a good rule of thumb in estimating distance/max speed/etc by looking at engine watt rating, battery v/ah rating and other factors?

Is a 500w engine big enough? Is there a difference between two identical battery packs other than distance on a 48v/20ah vs 72v/20ah vs 48v/10ah, etc. Maybe top speed or acceleration but then you have to consider your controller? I have a basic understanding of volts/amps/watts and how they relate to one another.

 

[nomad85]

Speed of around 40-45 at the top end

- A 9x7 9c hub motor will do 40mph with 20s of lipo

Range of around 40-50 miles

At what speed?
Forum member tostino has a recumbent that will do 45 mph in florida, you might want to see if he is local to you.

 

[TylerDurden]

tostino:
New Port Richey

http://endless-sphere.com/forums/memberlist.php?mode=viewprofile&u=6165

 

[jpullen88]

new port richey is pretty far from me unfortunately. I tried reading through the manufacturers to avoid/go to threads but they seem wickidly unorganized and impossible to find something if you dont know what your looking for. I only know of ebikes.ca. Can somebody post a list of good websites to search on? The motor list thread seems equally bad to me. It reminds me of reading chemistry books because I don't know the lingo.

 

[Drunkskunk]

ok so that doesnt sound like such a good idea, especially on the road bike. Would you recommend a MTB due to being easier to spot vs a bent? Also, the diy kits that i have seen online, what can i expect out of about $1000-$1500? I know this is a difficult question to answer. Is there a good rule of thumb in estimating distance/max speed/etc by looking at engine watt rating, battery v/ah rating and other factors?

Is a 500w engine big enough? Is there a difference between two identical battery packs other than distance on a 48v/20ah vs 72v/20ah vs 48v/10ah, etc. Maybe top speed or acceleration but then you have to consider your controller? I have a basic understanding of volts/amps/watts and how they relate to one another.

Mountian bike at a minimum. Not just to be visable, but to handle the power being put through the frame. You really are in motorcycle teritory at 40mph+ A bike frame isn't ment to handle those speeds for long. TylerDurden is right aboput a DH frame. it could handle the speeds, but the handling sucks above 35mph.

a 500 watt motor can handle run ups to 45mph or more when modified. It can't handle those speeds for very long, but for hole shots or zipping down to the end of the street, they can be fine. its all about heat management. to sustain the 2500 watts you'll use at 45mph, you'll need a 2500 watt motor.

As for reasonable expectations, $1000-1500 will buy you a kit with battery capable of 25mph for 20 miles or so. If you want more, you won't find it in kit form.

As for a good rule of thumb, at 20mph and 36 volts you need about 1 amp hour of battery capacity for every mile you travel. as speed increases, the power needed increases eponentialy. 20mph uses about 500 watts. 40mph will need 2000 to 2500 watts.

 

[ryan]

I spent about $1500 for my rig (a DH donor). $1000 for batteries and $500 for motor/controller/throttle,CA. If you don't need torque, you can use a x5 5303 or 5304 for increased speed. I've been up to 45mph with some gravity assist on my 5305, and have travelled up to 45 miles (including at least 3,000 feet of climbing) on one charge. If I was on level ground, and didn't have to get anywhere quickly, I'm sure I could easily travel 50-60 miles on a single charge.

My motor, controller, throttle were bought used (1000miles on them), but were originally part of a kit (Phoenix Brute). But I bought the batteries from Headway, direct through Victoria... ($800US plus ~$200 shipping).

Apart from the raw goods of the ebike, I probably have about $400 in extra "stuff" -- $150 for the rack, $50 for pannier packs, $125 for chargers, and $75 for wires, anderson powerpoles, and other miscellaneous items and tools. Not to mention the cost of replacing broken items (I thought I could get away with a cheaper rack at first... so that's $50 down the drain).

I hope that helps.

Here's another source for new parts: http://www.crystalyte.us/

 

[dogman dan]

Yahoo! all you want is 45 mph for 50 miles? Is that all? Me too. But I got it with a roketta 150 scooter. Used, it was $700. Too bad our dreams don't come true eh?

But seriously this time, 25-30 mph is pretty easy, and carrying 50 miles worth of battery at that speed is definitely doable. That speed is more like 1000 watts, but motors called 500 watt motors do it all the time.

The simplest easiest route there lately is a 9 continent motor. Another good source for one besides ebikes-ca is E-BikeKit .com

The 9x7, 36v motor kit comes with a controller that can handle up to 60v, which allows the use of 48v lifepo4 or lipo batteries. At 48v, the motor will go 27 mph pretty reliably. Put it on a mountain bike with 26" wheel.

Another option is from High Tech Bikes. There you can get an aotema motor, often sold as wilderness energy kits. This motor is a tad faster, and does about 30 mph at 48v. A third option from ebikes-ca is a 2806(9x6) motor that is also a bit faster than the 9x7.

Trying to go faster, which is totally possible, will make 50 mile range very very difficult to carry that much battery. But a very practical solution for a 48v bike would be two 48v 15 ah lifepo4 batteries from pingbattery .com About 30 pounds of battery, It could be carried in a pair of panniers for better balance. You'd have about 40 mile range at top speed. Slowing down to 20-25 mph would give you the 50 mile range. With that much battery in the back, a front hub helps balance that out.

At this point, the problem is not so much how to get the big battery but how to carry it, especially with a bike with full suspension that has no triangle. For this reason, lots of younger guys with less back problems than I, run a hardtail MTB and carry lots of battery in the frame triangle.

I cannot advise strongly enough to start out with a more moderate bike, like a 9c on 48v, and get a handle on the problems before attempting a 45 mph bike. After a few months of riding on a 30 mph bike, you will understand a lot better what you want, what you need, and what the cost of a fast bike will really be.

But if you must go fast, then here's how. 9 Continent 9x7 motor, 72v controller( see Lyens in the for sale section), and 5s lipoly bricks from hobby city. 4 bricks in series will get you 72 volts, and going about 40 mph. ( see the 40 mph club thread) Four 6s bricks would get you to or close to 45 mph I think. This is what I'm working on now for a race. But to own enough lipo to go that fast for 50 miles would cost thousands.

For the hundredth time, a pic of my current commuter bike as an example of a bike with 60-70 mile range. With a ping 36v 20 ah and a ping 48v 15 ah battery in the rear, I can go about 25 miles at 23 mph on the 36v pack, and then another 20 or so on the 48v pack at 27 mph. 15 mph travel gets me into the 70 mile range area. About 25 mph is the max speed I want to go with that big a load on the rack.

 

[amberwolf]

It may be difficult to carry enough battery on a standard bike frame to do 45MPH for 50 miles, and it likely won't handle very well with the weight, unless you distribute it just right. And it won't be cheap to do it, either, as the higher power-to-weight ratio batteries get more expensive fast when you need that much of it, plus a charger or chargers to refill them in a short amount of time.

Another potential issue you should check into is the legality of riding that fast on an assisted bike; it's not legal everywhere (even though usually riding a regular bike that fast *is*), so be prepared for anything that comes of that.

 

[dbackmtb]

jpullen88,

You can't go wrong with Dogman's advise. He can speak lingo with the best of them but he doesn't need to, he's very clear on your options. It worked for me and I couldn't be happier on his recommendations!

 

[dozentrio]

a 500 watt motor can handle run ups to 45mph or more when modified. It can't handle those speeds for very long, but for hole shots or zipping down to the end of the street, they can be fine. its all about heat management. to sustain the 2500 watts you'll use at 45mph, you'll need a 2500 watt motor.

True if you are not cooling the motor. I am running about 1500-2000W through a 450W motor, and only blowing some air through it. It gets warm, but never more than warm. Running at 44.4V now, going to 55.5V as soon as my batteries get here. I am confident I can run 2500 continuous. But this is very inefficient, as a lot of the power is wasted as heat. Cooling the motor only moves the heat off the motor to the atmosphere, it does not cause the motor to not MAKE the heat. I predict I will hit about 38 mph using maybe 1500W at that speed (peak power consumption during acceleration, due to my gearing choices.) I chose my motor purely because it was cheap, and I never intended to go as fast as I am when I bought it. If I could decide again, I would pick a 3kW RC motor in a heartbeat. But yes, make sure your frame can handle the speed.

 

[dogman dan]

Yeah, after you figure out how to carry that much battery, then you get to start figuring out how to sustain that heat. In my climate, a 45-50 mph bike better have lots of holes in the cover. Motor heat will depend on lots of factors, but monitoring the temps inside the motor would be a must do thing for a bike that fast.

Part of why I suggested a 30 mph bike, at 48v, to find out about all the other problems invovled, including the legal issues and attitude of local cops, first before attempting a really fast bike. Or,,,

Find out where John in CR gets his 5000 watt hubmotors, and put one on a motorcycle frame so you can legally register and insure it as a motorcycle.

30 mph commuter, youbetcha. 45 mph commuter, pretty shaky ground, legally, range wise, liability wise. It just isn't a bike anymore at that point. The one I'm going to build is strictly for the track.

 

[justadad1957]

i agree with dogman on that

looking at a close to 50 mph "bicycle" is for the death race kinda stuff not really for normnal city streets

still trying to fly low and keep our heads down

 

[jpullen88]

thank you for all the replies, especially dogman =)

So i think you all are right, 40-50 mph would be pretty scary on a bike. There is a hill in gainesville and if i pedal like a mad man all the way down it i can get up to about 35-40 on my road bike. That's pretty scary, how could i forget about that? lol.

Would you recommend a front hub instead of a rear? I saw you said go that way for weight distribution and you have that setup, dogman. Also, some types of batteries don't live too long if you continuously discharge them past 50%. Do the lithium type batteries do this? I saw the ping battery guy stats you will get at least 1000 recharges. Is that 0% to full 1000 times? If thats the case then i may be able to get by with a smaller pack so i can ride 25-30 mph for ~20 miles.

One last thing, how exactly does the pedaling work with the motors? To put simply, extremely simply, i pedal w/o motor and go 10 mph. Then i turn motor on and run it going 10 mph w/o me pedaling. So if I pedal and run motor I will go ~20? Im sure it would realistically be more like 15-18 mph because of some circumstances out of my control, but is that essentially the jist of it?

 

[nomad85]

Not in my experience, what will happen is you will go as fast as you set your throttle, period. (maybe 2-3 mph+ if you really pedal)
What will happen as you pedal is the amps used will go down (which could raise speed, since less amps=less voltage sag=more speed) resulting in longer range.

 

[Drunkskunk]

I saw the ping battery guy stats you will get at least 1000 recharges. Is that 0% to full 1000 times? If thats the case then i may be able to get by with a smaller pack so i can ride 25-30 mph for ~20 miles.

No battery can handle 100% discharge all the time. Really good lithium can handle doing 100% discharge on a few rare occasions, but doing it can shorten the life of the battery. Its best to not take a Lithium battery below 80%.

One last thing, how exactly does the pedaling work with the motors? To put simply, extremely simply, i pedal w/o motor and go 10 mph. Then i turn motor on and run it going 10 mph w/o me pedaling. So if I pedal and run motor I will go ~20? Im sure it would realistically be more like 15-18 mph because of some circumstances out of my control, but is that essentially the jist of it?

It works something like that. But the motor putting out enough power to go 10mph, and you peddling enough power to go 10mph combined won't equil 20mph. the problem is that wind resistance isn't linier, the faster you go, the more it increases exponentialy, so doubling your speed takes roughly 4 times more energy. combined your efforts would be more like 12-13mph.

However, if you run the motor for distance, enough to go 10 miles, and you can pedal 10 miles distance worth, the combined effort would give you 20 miles distance.

 

[dozentrio]

This shows how fast you will go under a given power. I think average person can maintain 150 watts for a pretty long time? I heard somewhere that Lance Armstrong and co. can maintain 400watts continuous.

Wind resistance is exponential (square law, I think?), but the coefficient depends on a couple of things. Commonly estimated by drag coefficient, and largely dependent on frontal area, and the smoothness of your surface (cyclists tend to not be very smooth, compared to an aerodynamic shell). If the airflow is laminar or turbulent also makes a big difference. I feel like I'm babbling a little bit. The point is, that chart is valid if you assume you're on a road bike, and compares aerodynamic position vs normal position, or something. Hope that helps

 

[jpullen88]

No battery can handle 100% discharge all the time. Really good lithium can handle doing 100% discharge on a few rare occasions, but doing it can shorten the life of the battery. Its best to not take a Lithium battery below 80%.

I think i have seen around here people say you try and figure out approx how far you need to go. Say this is ~10 miles round trip. Then i should shoot for a ~20 mile range battery pack. That would make sure that i never, or very rarely, use more than 80% of the batteries total capacity, correct?

Oh btw, how do you guys rate the wally world 100-150 dollar special bikes? I have an aluminum road bike w/o suspension and seems i should look into a mtb. Do i need to drop a nice wad on bike to convert or will i do fine /w a steel framed beater from Walmart?

 

[amberwolf]

If you're not looking for suspension, an older cromoly (chrome-moly, chromoly) steel frame bike is easy enough to find used in good condition for probably less than $50. Many could take whatever front suspension fork you want to use on it. Some can also be found with rear and/or full suspension cheaply. Front suspension forks can also be found used, just look for the steel forks that people pulled off their MTBs when they put higher-end forks on (that are often aluminum).

All would be lighter than the walbike and probably stronger/stiffer, as most of the walbikes I have seen in person or owned are thick/cheap steel that weighs significantly more for less strength/stiffness.

If you intend to put batteries in the frame rather than a rack or front/rear panniers, pick the bike with that in mind, so that your rear suspension doesn't interfere with that.

 

[dogman dan]

Lots and lots of factors come into play with bike choice. One of the main things about the bike is that the best bike is a piece of crap if you ride it out of adjustment. If the derailurs are out of whack, the brakes rub, and spokes are loose the bike will be trash. On the other hand, a cheap wally world mongoose can ride pretty nice if kept tuned nice. This results in wildly different evaluations of what kind of bike is the minimum.

I ended up going through a pretty predictable progression on my bikes. Starting with a schwinn trike, and carrying 40 pounds of lead batteries, I started having big problems with my lower back, and bending up wheels. My route to work has these really big bumps on the bike path for water to cross the path. Fine at 10 mph, but at 25 mph, you get airborne. The 30 miles a day ride length was a big factor here too.

Next was a cheap mongoose full suspension bike. A real trash bike, but as long as not asked to carry too much weight, it worked suprisingly well for 5500 miles. This bike has really crappy suspension, but the up side is that the front forks dropouts are very strong steel. So no worries about the front hub motors. Fitted with a 15 pound lifepo4 battery, the bike has decent balance, and the primitive suspension keeps the wheels from falling apart so fast. As I began to own more battery and try to ride longer distances, I found the frame was not so strong, and loading up the rear panniers became a big problem.

Now the bike in the pic. A very expensive bike new, I got it pretty cheap. It's frame is nice and strong and it easily carries 50 pounds on the rear rack. Sure, handling is dramaticly different then, but a corner at 25 mph is still ok. This bike creates a whole slew of new problems to solve though, because of the alloy frame. The cheap bike had steel on either end, and only the main section of frame was alloy. On the giant, it's alloy on the whole thing. Experience with steel bikes is a good idea to start with before tackling installing a motor on alloy bikes. Or tap into an experienced E bike builder if one can be found nearby and pay him well for the install.


The in between bike Amberworlf mentioned is a great place to start though. Priced new for around $200-$300 , hardtail mountain bikes may still have the steel front fork lowers even if the frame is alloy. Or at the lower end, the whole bike may be steel. Some of the schwinns at wallmart are a good example of this kind of bike, with RST front forks. Great choice for a front motor, since the forks can handle it, and you might scare one of these bikes up at a garage sale under $100. Or even cheaper if the bike has no suspension.

Pedaling the bike is another story. Some of my tests suggest that at speeds of 25 mph, pedaling enough to increase the speed to 27 mph can take a 100 watt effort of pedaling. On a light bike, if you weigh less than 150 pounds, 100 watts would get you 15 mph, but on a heavy ebike, and my weight of 180, just getting 2 mph more is hard work. So it's pointless right? WRONG!

You will gain a lot of range by lowering the watts the motor needs to go 25 mph. On an hour long ride, if the motor needs 100 watts less, that's a full 100 watthours. That can be 15-20% of the battery capacity, so range can be extended noticeably by pedaling briskly in a high enough gear. Above 25 mph, most mt bikes cannot be pedaled though, since they are not geared as high as a road bike. Even more dramatic range extension is done by simply slowing down. The range at 20 mph is much much longer than at 25 mph.

Another thing about pedaling or slowing down, is that it dramaticly lessens the strain on the battery, helping it to last longer. The 100 watts you supply means the battery takes it that much easier the whole ride.

On bikes with 36v batteries, a real good rule of thumb for battery size is 1 ah per mile. This rule insures that the battery is big enough for 80% depth of discharge on your ride most days despite hills, wind, etc. I get about 23 miles out of a 36v 20 ah battery when riding full speed till it's 100% discharged. Slow down to 20 mph, and I get 30 miles. Easy to see why so many ebikes are designed for speeds under 20 mph.

A 48v battery will let you go faster, so figure about 1 ah per .75 miles at full speed at 48v. That's about 27 mph on the 9 c motor.

 

[jpullen88]

The more i read the more it sounds like i would do better with some type of suspended trike or even four wheeled quike (i know, wtf right?). Adding one or two more wheels just seems like it would enable me to drastically increase range because id be able to carry a lot more batteries. Also, i would think, it would be either equally or more stable than a bike at higher speeds. This type of design could be dramatically more aerodynamic but you would be harder to see. However, what if you made some type of F1 breakaway pod? That way the driver is contained in some hardy ball so if struck by a vehicle it just rolls a hundred feet or so and then you crawl out saying that was a wicked roller coaster. Further, you could put insanely high gearing in it so that you can still pedal when going 30-40 mph (mostly just because i like pedaling, lol). What are the pros/cons of doing it on a mtb vs doing it on a trike (tadpole/delta)? You guys probably think im a quack now.

 

[Drunkskunk]

You guys probably think im a quack now.

Yes.
But we're all quacks here. Some of the best ideas came from general quackery

a 3 wheeled recumbent trike like a delta (one wheel in front) or a tadpole (1 wheel in the rear) would be more aerodynamic. and since wind resistance is the biggest factor on how far your battery will take you, you would go further.
But you're below the sight line of drivers. Out of sight, out of mind, out of luck.
4 wheeled bikes are illegal in some places. If you put a motor on one, the courts may decide 4 wheels and a motor is an unregistered, un inspected, uninsured car. Check your local laws real carefully.

Those Safety pods work by letting the car be destroyed around them to absorb the energy. They use the mass of the engine, suspension, and chassis to absorb and redirect the energy of the crash. If a car hits you in an unbreakable pod on a bicycle, you'll hit the inside of the pod as hard as you would have hit the grill of the car unless you have something to transfer the kinetic energy of the impact into.

 

[jpullen88]

Yes.
But we're all quacks here. Some of the best ideas came from general quackery

good to know, lol.

a 3 wheeled recumbent trike like a delta (one wheel in front) or a tadpole (1 wheel in the rear) would be more aerodynamic. and since wind resistance is the biggest factor on how far your battery will take you, you would go further. But you're below the sight line of drivers. Out of sight, out of mind, out of luck. 4 wheeled bikes are illegal in some places. If you put a motor on one, the courts may decide 4 wheels and a motor is an unregistered, un inspected, uninsured car. Check your local laws real carefully.

Excellent point, i hadnt thought of the laws associated with a 4 wheeled bike, and to think i just took a class in criminal procedure =(. I get the feel ebikers have been here before. Considering safety, speed and range. You get more speed/range with the bent but less safety because your out of sight. I see why many people choose mountain bikes. Also, its cheaper.

Those Safety pods work by letting the car be destroyed around them to absorb the energy. They use the mass of the engine, suspension, and chassis to absorb and redirect the energy of the crash. If a car hits you in an unbreakable pod on a bicycle, you'll hit the inside of the pod as hard as you would have hit the grill of the car unless you have something to transfer the kinetic energy of the impact into.

After posting, i researched the pods a bit more and found that to be the case. In many circumstances average cars are meant to break and crumble in certain areas in order to dissipate that force you speak of.

Do you suggest i stick the motor on the front or rear wheel? I always thought rear would be an obvious choice but is front better in order to spread out the weight load?