Yes you can convert just about any ordinary bicycle into an electric bicycle.
In US about half of the e-bikes on the road were once an ordinary bicycle. (In europe less so, because they are less DIY there)
Many brands of electric bike were made as on ordinary bike frame and the electric bike factory added motor and the battery.
You need to think about where to put the motor and battery.
If you have any rear wheel gears other than the very ordinary screw on gears then you probably won’t want a rear hub motor. There are not many rear hub motors that can keep your casssette gears ( if you have those) and they are more expensive.
If you have rear sprung suspension then you can’t add a rack above the wheel to hold the battery.
Otherwise you can have the motor in front or rear wheel, or centrally near the pedals ( See E-Bike Motors – front, rear or mid) and the battery on a rear rack or attached to down tube, seat post or anywhere else it fits.
There some forums where enthusiastic devotees of DIY conversion describe (brag about) their conversions. For instance Endless Sphere
There are countless videos on YouTube about bike conversion. Just search those words and there are so many to choose from. If you need to you can get confidence from a few of those. But probably you won’t need to because converting your bike with a basic front or rear wheel conversion kit is quite easy.
There are many shops selling a basic conversion kit. There are also many on EBay. Many of those will not be in stock locally and will come from China. You can get a conversion kit direct from many sites in China yourself, but do make sure about what you order.
You will see a picture like this
These include a hub motor and a “controller” that connects to it and either or both a throttle and a pedal assist sensor. One or a pair of brake levers are usually included. They replace the brakes that you had and are added safety because they stop the motor when you brake. They are not essential but recommended for safety. If you have a brake and gear shift combined you can keep them but they won’t stop the motor. Increasingly an LCD screen showing speed, distance and more is included.
Most of the conversion “kits” will include a battery. However most shops will sell the wheel and controls separately from the battery. The battery is the most expensive component of a conversion. In general any battery of appropriate voltage and capacity can be matched to the controller of the motor. You are likely to get a better total price if you shop for battery (and rack or attachment) separately.
This year 2014 “smart wheels” will start to be produced. These are all-in-one conversions and may be a suitable simple easy conversion for some. See Smart wheels – a simple easy conversion
Next posts : E-Bike Conversion – Front or Rear Hub
E-Bike Conversion – Central Motor