Fast…long range…cheap. The E-bike equation says you can have two of those things but not all three. This article is a way that you can get all three. A 30-MPH, 20-mile range, $1000 electric E-bike. A feat that just a few year ago would have been probably impossible. But because of cheap sourced E-bike components direct from China, it has become possible today.
30-MPH is fast for an electric bike. And 20-mile range is far for an E-bike. There are many manufacturers around who will claim these kind of numbers, but the truth is there are only a handful of bikes on the market currently that can go this fast and this far….and the ones that actually do that are very expensive.
The only choice if you want to go 30-MPH on an E-bike, and have a decent range, and you want to get it cheap, is to build the bike yourself.
The most difficult part of this task will be sourcing. In this article I will show you how to cheaply source all the quality components that you will need to build a $1000 bike. I have no relationship with any of the vendors who I mention below….
To achieve 3o-MPH you are going to need to run 1000 watts to a motor that’s at least 80% efficient. The easiest way to do this is run a 48 volt battery at 25-amps and you achieve just under 1000 watts. You can later upgrade to a 40A controller, but then you are taking a chance of smoking your motor if you run it too hard. To achieve a 20-mile range with moderate pedaling and cruising at a 20-MPH speed you will need roughly 500 watt hours of battery. A 48V / 10-AH battery is 480 watt hours which gets us pretty close to our objective.
Once you have chosen and sourced all the components to complete your build, its time to read our one hour ebike conversion story here to learn how to build your E-bike in one hours time (longer if you’re not mechanically inclined)
To accomplish our goal we are going to start with a used mountain bike. There are many decent mountain bikes for sale currently that are inexpensive. Craigslist is an excellent source for finding a locally available used mountain bike.
$220 Craigslist Donor Bike
This is an example I found off my local SF bay craigslist. This is one of many suitable bikes I saw on the one night I looked but this seemed like the best candidate. For reference sake, here is the text of the craigslist ad of the bike in the above picture :
2010 Specialized Hardrock Disc Mountain Bike – $220
Size: 15″, Rear Disc Brakes only. No front brake. Shifters, gears work well. Leave contact number if interested.
A Specialized front suspension hardtail bike. This bike gets my rocks off. I love hardtail suspension bikes as a donor. Read my story here on suspension choices on donor ebike. This bike is set up for disc brakes. but only has a disc brake on the back. No big deal, we can just move that brake to the front, since our bike kit comes with its own regenerative braking system for the back wheel which will contain our hub motor. So in our case, we only need one disc brake anyway. I highly recommend that your donor bike come with disc brakes if you are going to build a 30-MPH E-bike out of it. Read more about picking a donor bike for an ebike build here.
$350 lifepo4 battery and charger
There are many decent LiFePO4 E-bike batteries on ebay. Before you choose a battery, you should read our article here on lithium batteries so you fully understand what you are buying. If you take my recommendation on a fast, cheap and decent bike, I would recommend a 48V / 10-Ah LiFePO4 battery. It’s known for being a very stable chemistry, and also for providing a long life span. I like a 48V battery because it will easily get you the wattage you need to get to 30-MPH. For this top-speed, its almost mandatory you get a 48V battery, because a 36V set up is just not going to give you enough juice. If you are happy with 20-25-MPH and have a relatively flat commute, then you might be satisfied with a more affordable 36V battery.
I did a search for “48V 10-Ah” battery on ebay and found many good LiFePO4 batteries, shipping straight from China.
In case the link goes away I will post the details here…but no worries, there is always an abundance of 48v 10aH LiFePO4 batteries on ebay and the number is growing every month.
|Voltage: 48 V|
|Lifecycle: >1000 times 85% capacity after|
|Charging Voltage: <59 V|
|Charging Current: 0~1.5C|
|Rated Discharging Amperage:10A|
|Max Continuous Discharging: 10A|
|Maximum Discharging Current:20A|
|Dimension:200x105x150 mm ( 7.9 x 4.1 x 5.9 inches )|
|The pack include :|
|●48V10A LIFEPO4 BATTERY|
Included in this price is shipping from China. This is taking advantage of China-direct pricing, which is very reasonable. This is the safest of the lithium technologies and should easily be good for 500 charges. The battery also includes a Battery Management System (BMS) which will make the battery safer and healthier during charging and discharging. This price also includes a 3-amp charger, which will fully charge your battery in less than 4 hours.
This is a large battery, with 480-wh which is bigger than what most commercial E-bikes give you. However for a more reliable bike you may want to go with a bigger battery, like 15Ah-20Ah because you can take more current out of it without damaging the battery.
With moderate pedaling added, you should be able to get a 20 mile range with this battery. If there is more money in your budget than $1000, seriously consider getting a larger battery. A 15-Ah size would be great, and even a 12-Ah size would be an improvement. The larger the battery, the easier it can supply the amount of current you are demanding from it, and the healthier it will be. Plus, more miles between charges is always good. Don’t even think about getting a battery smaller than 10-Ah, regardless of the voltage
$6 black gorilla duct tape
Since this is a budget bike, we will go ahead and just duct tape that battery in the center triangle using duct tape. This is actually a pretty good solution since the bike will be well balanced with the 10lb battery weight in the triangle. This solves where we mount the battery. Add some strips of scrap foam to everywhere the battery touches the frame, to prevent vibration from rubbing through the batteries thin cover.
$260 ebike kit + 160 shipping from china
The simplest way to build a cheap E-bike is to just buy an all-inclusive kit, so you don’t have to worry about which controller will connect with which motor and throttle. The wire color-codes and connectors are different for each manufacturer. The following ebay kit sold straight from China will come with everything else you need to make an E-bike, including the motor, controller, freewheel cassette, throttle, and even a rear rack bag.
The controller is good for 25 amps which at 48V will give you just under 1000 watts which should get you to 30-MPH on fairly flat ground with moderate pedaling. I found it here on ebay, and the picture above is of the actual kit so you can see what it contains. In case the link disappears you will find many similiar kits on ebay direct from China, probably even better and cheaper in the future. Remember China sells millions of E-bikes every year inside of China to its own citizens, so the price of this stuff direct from China is cheap because its made in such massive quantities.
When you buy any product direct from China with no middle-man you will save some money, but you will also be taking a chance that something will go wrong. Shipping an E-bike kit back to China for replacement or repair is not cheap. So consider paying the extra money and using a US-based retailer with a good reputation.
So lets total what we bought in our $1000 fantasy E-bike buy.
|Donor Bike $220|
|LifePO4 48 volt battery $350|
|E-Bike 1000w motor kit $420|
|Roll of black gorilla tape: $6|
|Total price $996.00|
$996 buys you an honest 1000 watt bike with 480 watt hours of lithium battery, that should give you a 30-MPH top speed and a 20-mile range with moderate pedaling in fairly flat conditions.
Again, to assemble the kit onto the bike, read our One Hour E-bike Conversion story here.
If anyone actually builds an ebike using these sources please keep us informed and be sure to document your build progress with pictures.
But again, this is just a sample of how to source appropriate components for a cheap and fast E-bike build.
Here is an example of a person who built a 30mph bike with less than $900, a respected DIY builder (John in CR) recorded riding in the hills of Costa Rica at high speed: