Anyone convert to an electric bike?

[johnintaiwan]

Sorry if someone posted already but the search function is having problems now.

Has anyone here converted their bike to an electric bike? I see a lot of kits online but they dont include the battery. I want a simple 250-350w  36V front wheel kit. I have found some online but they dont include the battery. Any idea on what capacity battery I would want? I dont know much about how to calculate my needs for this. The kits seem very simple to install, am I missing anything?

Any help would be greatly appreciated.

[MountainBeard]

I'm sure someone will have some better rules of thumb, but to get you started...

Motors are rated in watts which is equal to amps times voltage.  Batteries are rated in amp-hours.  So, if you're looking for a 36V system running at 350 watts, every hour of operation at full capacity will require: 9.7amps (350/36) - or stated, in terms of a battery 9.7 amp hours.

Of course you might also be pedaling, and you always won't be at full throttle so a 9.7 Ah battery should last a bit longer than an hour.  Also, remember that battery capacity goes down when it's cold out.

[Thegoblinchief]

Endless-sphere forum is where you want to be. If he's still active here, PM Ziggurat, but that forum is the holy grail of e-bike knowledge.

[Syonyk]

Endless Sphere is an amazing resource, but is also filled with a lot of slightly bonkers people who think 50mph on a bicycle frame/tires is somehow a good idea.

I commute to work on an ebike somewhat regularly (there are a few hills I don't get along with on my route, and not arriving at work sweaty and needing a shower is a major plus for me).  What would you like to know?

If you're looking at 250-350W, you ideally either live somewhere flat, or are just looking for a bit of an assist on hills.  The nice thing with front motors is that they don't require any work for the rear drivetrain, so are pretty heavily DIY.  Don't put a front motor on a bike with front suspension, though - the suspension systems are not built to take that kind of load, and you can cause them to fail in spectacular and painful ways.

As far as battery power goes, most ebikes pull 30-40WH/mi (watt-hours per mile), give or take.  You'll be on the lower end of that since you have a small motor and won't be able to power up hills without pedaling, so you might be able to size a bit smaller.

What are your goals for it?  In general, figure out your desired range, multiply that by 30 or 40 or whatever, add a fudge factor, and buy a battery.  I'm a big fan of LiFePO4 batteries as they're safer to charge (they don't tend to catch fire when abused), and have a radically longer cycle life (thousands of cycles to 80% capacity instead of hundreds).  They are a bit more expensive up front, though, and they're slightly heavier (which doesn't matter).

I'm running a ~1300W setup with a 500WH battery and I have a 15-20 mile unrecharged range with mostly motor power.  With that type of setup, you design the bike a bit differently, but for what you're talking about, keep the gearing the same and just ride it.

[johnintaiwan]

Thanks for all the advice so far. I started on the endlesssphere and on MMM's post but got in way over my head pretty quickly. Im living in Phoenix now (need to change the screen name) and am mostly just looking to pedal but have a little more speed or assist up hills. So far I have a few bikes to experiment on. I have an old huffy steel frame road bike (will have to change out the drop handles bars) and my dad's steel frame comfort cruiser.

does anyone know of any complete kits (with battery)? It looks like they are cheaper from China but you get killed with shipping and possible quality issues. When I search online there are a ton, but I can't tell which are reasonably priced and which are so cheap they will likely have problems. Im pretty confident I can figure out how to install it, but it is a big purchase and don't wanna spend a ton of money but also don't want to have to replace it after it breaks on me.

[Thegoblinchief]

I have heard excellent things about the ebikes.ca kits, so perhaps look at the parts they have and see if you can get similar with a battery (theirs seem to not have a battery included option):

http://www.ebikes.ca/shop/conversion-kits/direct-drive/crystalyte-front-hs-kit-basic-throttle.html

But have you looked on the used market in PHX? I occasionally see fully built ebikes for less than the cost of the constituent parts here.

When I've asked pro mechanics, most of them say they prefer Bionix kits, but I think those are all geared designs rather than front hubs, and $$$.

[Syonyk]

There are plenty of complete kits from high quality companies.  You don't want to pay the price for them. :p

http://ridebionx.com/ is probably the nicest "Everything together" kits you can find, for a couple grand each.  And not really much power.  But it's fully integrated, can do regenerative braking (slightly overrated, IMO), and is everything you need in one nice kit.

"Powerful, cheap, easy" - pick 2.

How much are you looking to spend on this project?  There are a lot of price points one can build to, and it sounds like you're suited to a lower one, based on your riding style (and the DIY-ness, since that generally cuts costs a LOT).

For a 250-350W kit, it's going to be hard to go very wrong.  It's just not that much power.  Also, really not that much money.

Get a motor/controller together, unless you're going with a brushed motor.  Then one brushless controller is as good as another.

The standard for a throttle now is a 5v hall effect throttle.  It's not an official standard, but everyone uses them.

For a battery, I'm a fan of LiFePO4 batteries, and batteryspace.com has a nice selection.  You can get cheaper with other lithium chemistries, but don't go with anything else.  They're not worth it.  Seriously.

Figure out how far you want to go, and get a battery to fit.  As I commented earlier, if you budget 35WH/mi, you're probably pretty close, but if you're going to be pedaling a lot and using the motor just for hills, you can get away with a lower figure.

Anderson connectors are awesome for connecting battery to controller, and most other connections you have to make.

[BikeFanatic]

I have been riding electric bikes for over ten years.  If you
Need any assistance let me know.
I would recommend a small geared motor. The  BAFANG Bpm or swxt, Or similar.
I second Ebikes.ca also Ebikekit.com in philly.Then there is   a company in China called EM 3 Ev they have really good battery also.
You can get away with a ten amp hour battery 48 volts that will get you 10 12 miles depending how much you weigh and how much you pedal.