It's time to continue with the affordable methodology in the task of converting a common bike to an electric vehicle. Lithium-ion batteries use a well-understood technology that provides different specifications, but the most important ones for an average user are charging cycles, voltage and current. No rechargeable battery last forever, even they experience some issues like self-discharging in dependency of several elements. Lithium-ion doesn't lose too much per month and you could expect more or less 1000 recharging cycles. The battery will work, although has lesser capacity.
Then, someday the user needs new batteries, so the procedure is to buy the 18650 model and install the batteries by him or herself even without using a single screwdriver! That way the inversion could last, as any other should, enough for the entire life. Or with another new bike, the same conversion kit!
Now some performance calculations with these 18650 batteries. This battery has 3.6V, so for instance, assuming a pack of 10 batteries for an electric bike, the voltage adds up to 36V.
The state of the art as of today in capacity are 3400-3600mAh, or with other words, 3.4-3.6 amperes-hour. A ten pack adds up to 34-36 amperes-hour. That means, as you probably know or guess, that the battery pack is capable of giving 34-36 fixed amperes during one hour. After that, it would be empty!
For getting the power the formula is straightforward: Power is equal to current multiplied by voltage thus selecting the 3400mAh ones, 34 * 34 = 1156 watts-hour for approximately $145 / 105€. That's a good price for these batteries nowadays, and for a top capacity. With less amperes-hour (about 20Ah), that price could easily drop 50% or more.
After having the batteries, it's time for acquiring the conversion kit! Here or there, the price shouldn't surpass $150/110€. The necessary pieces are the enclosure for the batteries, the DC motor and the throttle mechanism.
Nevertheless the prices are only assured for the battery pack. Other places could present a 500% of the aforementioned price or more. In part three of the article we are going to provide some other suggestions and sources for purchasing at an interesting price in our opinion, and without being nor minimally related to the web sites!