Ok boys and girls, I’m not affiliated with any of the sellers listed here, but click through and order something, and I’ll get a little kickback from Bezos.

First and foremost, we have the most popular diy mid drive on the market today, the Bafang BBSHD. Yes it’s Chinese, no it doesn’t have a torque sensor for seamless pedal assist like the high $ European/Japanese/American mid drives. But if you like power and want to run a thumb or twist throttle it’s a good choice. Keep in mind that this may not be street legal in your jurisdiction!

If you want to remain street legal, the Bafang BBS02B is the next best thing. At 750 watts rated output, this allows you to qualify as a bicycle in most of the US. Quiet, compact, cheap, and fairly reliable.

If you don’t need all that power and weight, prefer the feel of a torque sensing mid drive, or want a slightly stealthier drive, the TongSheng TSDZ2 is a good choice.

Next, if you want to go cheap and stone simple, the Voilamart direct drive hub motor is a popular choice, and costs about half of a mid drive. Again, this may not be street legal where you live at 1000W.

Finally we have the trusty Bafang geared hub motor. These are a good choice for a low power, stealthy build that can still climb hills without bogging down. Not quite as cheap and simple as direct drive because of the internal planetary reduction gear, but easier to install than a mid drive kit.

Last but not least, many of these kits have an optional battery that will come with the correct connectors to mate with the motor and controller, but it’s possible with a bit of soldering to hook up any battery of the appropriate voltage and amp output capacity to any of these drives. I’m currently running a Unit Pack Power 52v battery that’s compatible with most 48v motor controllers for a little extra oomph on commuter.

That battery offers plenty of power for my 10mi round trip commute, but if you need or want more range, 20ah or larger batteries are available, and often come in a convenient triangle pouch that lets you motorize a frame that lacks appropriate bosses on the downtube to run a hard case battery. Inside is just a shrinkwrapped brick of 18650 cells with a battery management system (BMS) to keep them balanced and healthy.

Keep in mind that a bigger battery will not only last longer per ride but will last longer over its life for a given use, as deep discharge cycles are the enemy of lithium battery cells. You will also lose range over time as the battery degrades, so a pack that can get you home and back on day one may not have enough capacity after a couple years of use. They say the only time you regret buying a bigger battery is the day you have to pay for it.

If you have a long commute or need to hit a particular range, you can run your proposed setup through an online battery calculator like this one and determine if you have enough juice to get the job done.