Thinking of converting a bike to electric - where to start?

[atomicthumbs]

I've decided that an electric bike would be better than a car in terms of costs and mobility for me. I'm not sure where to start in selecting parts or a kit, though.

I live in an area that's both hilly and flat - most of my commute is flat, but there is one long, steep hill that I'd have to go up on the way back. I'd also like to take it up to the open space fire roads around here.

I'm not sure where to start; there are too many parts, and too many prices and values. I'm planning on getting a non-SLA battery, but I'm not sure what kind to choose. I've also heard that chain-drive motors have advantages over hub motors, but I'm not sure what they are and if it's worth getting one.

I have a 2006 Schwinn Mesa GS hardtail bike, with a front suspension fork. Would it be good for conversion, or is it a better idea to buy a different bike? Can rear hub motors and/or chain motors be used on bikes with rear suspension?

 

[spinningmagnets]

Is this the model? do you have a front disc brake (or, at least the FDB flange mounts)?

 

[atomicthumbs]

Pretty sure that's it. I don't have a disc brake, and the shifter (and maybe the derailleur) on the rear aren't stock because my brother managed to break the derailleur off on a rock, but it's pretty much exactly the same as in the picture.

 

[torker]

How far is your commute? How steep is the hill? Welcome to the forum..

 

[atomicthumbs]

My commute's about 8 miles each way. Not sure how to properly quantify the hill's slope, but it appears to drop 400 feet over about a mile according to Google Maps' topo view. Might not have done that correctly, so it might be steeper; it's Sir Francis Drake Boulevard in this map. I'd also like to take it up in the fire roads to the southeast of that view, but I'd probably be walking it up those as I'm not an avid mountain biker

 

[spinningmagnets]

Welcome to the forum. Lots of choices as you've mentioned.

The Bottom-Bracket (BB) drives like the Cyclone/Elation are somewhat pricey, and the Cyclone has some weak components that will likely need to be replaced soon, and then with an upgraded part. They are noisy, but the chains give the motor the use of the bikes gears, and will give you both good top speed and good hill-climbing. If you can put up with noisy and expensive, that may be the ticket for you. If yes, I highly recommend getting the 650W kit at a minimum. Heat will be the big issue, and the 650W kit has a separate controller, instead of the integated motor/controller that cuts out from heat quite easily, due to its inability to shed heat well. Also buy the extra aluminum fins for the motor. (getting everything installed and adjusted is quite complex, are you mechanically inclined?)

If you only had a flat commute, you could get a pleasing 23-ish MPH from a reasonably affordable 36V pack using the popular ebikekits.com version of the 9-Continents (9C) 9X7 hubmotor, but it is not a good climber, it will slow down on steep hills and get hot. Direct-Drive (DD) hubmotors can run near-silent, and are very reliable due to their simple construction. IF...you are willing to give up a high top-speed, you can get a DD hub that is a good hill-climber...

The 9C (and its clones) has a popular winding called the 9X7 or the 2807. The "7" in both numbers refers to how there are 7 wire-turns on each stator tooth. There is only so much room for copper on each tooth, so you can have more turns of thinner wire, or fewer turns of thicker wire. I believe they are readily available in 6-turn, 7,8,9,10, and 12. A low number is higher speed-per-volt applied, higher number is lower speed per volt, but less bogging down and heat on hills.

If I remember correctly from reading here, an 8X8/2808 (meaning 28mm magnets/8turn) using 48V will climb reasonably well, and still provide around 23-MPH on the flats (I believe cell_man is selling these). No way to know how it will do on your particular hill, but if you need a better hill climber than that, Ypedal is selling a 6X10 that runs about 19-MPH @ 48V? but will climb even better(edit: Torker is correct in the post below, it is Methods selling 8X8 and 6X10 http://endless-sphere.com/forums/viewtopic.php?f=31&t=24515 ). He has an even slower 5X12 which I suspect would run near 15-MPH @ 48V, but you should be able to get near 20-MPH on 5X12 with a more expensive 72V battery and controller. Much is dependant on your budget and preferences.

Quote from Dogman:

9 continent 2807 kit with 22 amp controller will reliably do 27 mph using a 48v 15ah pingbattery. Range at that speed will for sure be 15 miles

Quote from drunkskunk:

9X7 @55.5 Volts 22A controller, 29mph top riding speed
6X10 @55.5 Volts, 22A controller, 24mph top riding speed

I have no experience with these, this is just info I gathered for my own research. Plan on using 48V and then choose the slowest motor-winding you can live with. If you get a Ping battery, use a 15aH size minimum to avoid voltage sag.

9X7 from ebikekit.com
http://e-bikekit.com/ebk-system.html

8X8, 6X10 from methods
http://endless-sphere.com/forums/viewtopic.php?f=31&t=24515

8X8 from cell_man
http://www.emissions-free.com/catalog/i14.html

9C info from ebike.ca
http://www.ebikes.ca/store/store_nc.php

A review and comparison between the 9X7 and the 6X10 (8X8 performance is halfway between the two)
http://endless-sphere.com/forums/viewtopic.php?f=4&t=18782

Here's a spreadsheet to show the top speed of the various 9C windings per volt applied (also various wheel diameters):
http://endless-sphere.com/forums/viewtopic.php?f=3&t=21390&start=165#p367364

 

[torker]

Just to clarify Methods is the one selling the 8x8 and 5x12 motors.
Like Spinningmagnets said though a direct drive hub motor will be a compromise between speed and hillclimbing. A 6x10=slow- would be a good climber but 20 mph. max. at 48v. A 5x12 is even slower but would be an awesome climber but the ones Methods has are laced to a 20" rim so not the best for your bike. Those are just a couple examples. There are also geared hub motors that climb a little better than a direct drive but won't take higher voltage as well. A chain drive setup like Cyclone is the best of both worlds because it runs through the gears so the motor stays in its happy zone up near its max rpm. Electric motors don't like to lug. That is why direct drive motors suffer climbing hills.
Lots to consider I know. Depends on how much mechanical skill you have and how fast you want to go.

 

[atomicthumbs]

Thanks for all the information!

(getting everything installed and adjusted is quite complex, are you mechanically inclined?)

How complex are we talking here? "Know how to use tools" complex or "fabricate your own parts" complex? I know how to use a lathe, bandsaw, drill press, welder, etc. but don't have access to any of them right now. There is a community bike repair thingy near here which might help, but I've never been there.

Taking a look at the website of said bike repair place revealed this; are any of those kits a good value? I'll probably buy one online anyway, and they don't offer either of the chain-drive kits you mentioned.

Is the LiFePo battery in the eLation kit a good value, or should I find something else if I end up buying it?

 

[spinningmagnets]

This is the battery I'm recommending for a 9C hub, based on what I have read, I will be buying one in 2 months. Ping 48V, 15aH, $500 (Cyclone 650W is a 36V?)
http://www.pingbattery.com/servlet/the-12/48V-15AH-V2.5-LiFePO4/Detail

As for a BB-drive (made famous by Cyclone, Taiwan is very hilly), the freewheel inside the BB is known to wear-out early (you need the upgrade $100 ENO), This BB-freewheel allows the motor to spin the chain while the pedals are still. You must remove the pedal-axle and replace the BB parts, Heres an example:
http://www.cyclone-tw.com/
Cyclone parts swap-in pictoral:
http://www.cyclone-tw.com/3chkit.htm

 

[atomicthumbs]

So a bottom-bracket mounted motor would necessitate me replacing the freewheel in my bike, or is this replacing a part that would come with the motor?

 

[torker]

It would be replacing a part/freewheel/ that comes with the kit with a better freewheel as the ones that come with the kit have not held up very well. If you search this site for Bottom bracket/ cyclone/mid-drive you will find info. Basically when you run a bb-drive it comes with a longer axle for your bb and a freewheel that replaces one of your crank gears so you can drive the crank without pedaling. Otherwise the motor would drive the crank all the time.

 

[spinningmagnets]

Heres a review of a 650W Cyclone
http://endless-sphere.com/forums/viewtopic.php?f=4&t=7436&p=113154

and, the 500W Cyclone
http://endless-sphere.com/forums/viewtopic.php?f=4&t=506

Its my undestanding they are the same kit, but the 650W has a different winding to provide the same RPMs at the higher 36V (500W is 24V), and the 650W controller is separate so the motor and controller both shed heat better.

Here's the thread I've been looking for, good pics of a Cyclone install...
http://endless-sphere.com/forums/viewtopic.php?f=28&t=14479

Plus, when you want to upgrade parts, heres the freewheeling-BB thread from the non-hub resources stickie (thanks Miles!)
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=7192#p165215

 

[auraslip]

Look at cell-mans threads in the for sale new section about geared hub motors. I

He also sells a123 packs, which while pricier than ping per AH have a higher C rate. For example, you wouldn't want to run a 48v15ah ping on a pc 9x7 from ebikekit.com. You could, but you'd have to limit the controller to only draw 15 amps (1c). That'd be a slow, unfun ride. This means you'll need the 20 ah pack. Which cost me like $800, and weighs 20lbs. Overkill. I get about 35mile range on my 9c + ping 48v20ah. I've never run out.

For $600-700 you could get a 48v11ah a123 battery, which would be perfect for your commute. As a plus it'd be LIGHTER by a lot, and a123 are 10c. That means you could pull 100 amps out of the battery pack!

With ping you'd be stuck with a big reliable battery that'd you'd have long after you've decided to upgrade to something MORE FUN, and believe me YOU WILL !

With the a123 pack you could get an extra 24v pack to upgrade to 72v with no problem.



Start modest though. Building a bike over 25mph is expensive. You gotta upgrade stuff like brakes, tires, and lights. Around 20mph efficiency takes a nose dive and the price in battery really increases. I might start off with a 36v pedal assist. A very quick pedal assist though

 

[dogman dan]

I think an 8x8 from Methods would be a great choice for you. Just a bit better motor for hills. The Ebikekit motor is fine too, for the street hills. 400' of vertical in a mile is no problemo for either of those motors. Run it on a 48v 22 amp controller and 48v battery and you should be happy enough. You could hardly go wrong to just go to Ebikekit.com and buy the direct drive kit.

However, if you want lower speeds, and even better hill climbing then the 6x10 motor is very nice. Better is defined not as faster, but rather by the motor can climb steeper hills without stalling, and overheating. So the 6x10 is slower, but makes it up longer hills without melting. Perfect for those fire roads.
Top speed on the 48v battery with the 6x10 motor is about 19-20 mph.

Rear motor on both of these, since you want to ride dirt. Front hub is great, I love it, but only on pavement. Front hubs spin too much on dirt.

The cellman gearmotors are not aimed at climbing fire roads, but would do the street rides you speak of. His direct drive motor is comparable to the ebikekit motor.

Battery is another topic. Giving the hill climbing, you'll prefer 48v. If you have a long ride to do, the 48v 15 ah lifepo4 from pingbattery is one excellent choice. Very trustworthy vendor selling a good product for daily commuters with long rides. 15 pounds of weight.

For a lighter, cheaper, but still very very powerfull battery, many of us go for the lipo from Hobby king. A tiny little 5 ah pack can weigh less than 4 pounds, and still crank out the amps at 45 volts. This would be a pack made of two 6s 5 ah lipo packs. Not much range, but a lotta wow for a 4 pound battery.

In any case, mount the battery in the triangle of the bike. The pingbattery may fit , or not depending on the frame size.

How long a commute? About .75 ah per mile of 48v battery is my rule of thumb for battery size.

 

[auraslip]

Cell_man just posted in his sale thread wrt to a 16s4p a123 pack - 48v9.2ah - $450 + shipping + charger. The 15ah ping is $500 + shipping. They should come out to the same price. Dogman and I both love our pings but if I could go back in time (and if cell_man was making packs a year ago) I would have definitely gone with the much better a123. It's the best lifepo4 battery at this current time. Only thing better is Lipo - but that's a whole lot of complication - a diy lvc - and a charging setup - Not very good for plug in play charging like at work. And the chemistry has a 300-500 cycle life vs lifepo4 at 1000-2000. So if you are replacing a car with a bike, it makes more sense economically in the long run. Also maybe in the short run, depending on how much you spend on chargers, but I'm no expert in that area.

Dogman, what's the deal with the mac geared motors? They're more powerful then the $150 geared hub motor kits right?

 

[atomicthumbs]

Would the eLation 300W kit be a good fit for me? I'd like to buy that 15ah Ping battery, but then I'd have to build my own housing (unless there's one available).

 

[jimw1960]

Making a battery housing is something you will have to deal with for any battery or motor kit. Here is a good thread where folks show a variety of solutions. http://endless-sphere.com/forums/viewtopic.php?f=3&t=12847

 

[auraslip]

Here's a nice summation of battery housing choices.