Leed's little PBJ

[emco5]

I tend to tinker with bicycles a lot during the dark months. Last autumn, I was tossing around some ideas for a simple power system using an RC LiPo battery pack with a friction drive. I wanted to power a bike but keep it as lightweight as possible. Inspiration came from ‘Kepler’ in Australia who has built some functional minimalist designs. While gathering battery data and sources I came across Leed’s PBJ battery. That mini battery with their Bafang 250 watt geared hub was a far more efficient setup than a friction drive. It was also sorted out... plug-and-play. So, I invested some lunch money and got the PBJ package.

There isn’t much labor involved to install a small front-hub system: replace stock wheel with the new wheel, route on/off switch to handlebars, and mount the battery someplace. I wanted my bike to not look like an eBike, though. So, I spent additional time securing the wires with clear tape instead of using zip ties, and hid the battery and controller in a small frame bag. I also laced the motor into a matching rim.

It worked, and I now have several hundred miles on the bike. Leed claims that the little motor with the PBJ will run for 4 miles. I agree with that. If the route has moderate hills, though, and the power is used conservatively when climbing, expect two or three miles. As I’ve mentioned in another thread, a 250 watt geared hub does not generate a lot of energy, it’s an ‘assist’ motor. A 250w mid-drive is massively stronger for climbing, but the PBJ can’t be beat if you want a stealthy eBike. It can ridden on pedal-bike-only paths unnoticed, but I rarely use the motor on those mostly level routes. Where it shines is getting me back home up a few hills, and then it’s a very welcome boost after a long ride.

 

[harryS]

There's lots of good reasons to have a high powered bike, and also good reasons to have a low powered one too. You can ride with a group of slower riders. You get more exercise. And they sip battery power, so a little battery can get you around for up to an hour. And they can look like a regular bike. Nice looking bike in your picture!

Does Leeds upgrade their package with a throttle and PAS these days? Makes for a more versatile ride.

 

[emco5]

..Nice looking bike in your picture!

Thank you. In stock form it was an inexpensive 7-speed, but was upgraded with second-hand components.

Does Leeds upgrade their package with a throttle and PAS these days? Makes for a more versatile ride.

Leed has, so far, refrained from adding complexity to their 250w hub systems. For me, that K.I.S.S approach is the value. The PBJ works great as a simple on-demand boost motor with the on/off button. If it had PAS, the motor would be constantly drawing down the battery which would then require a larger/heavier battery. Pedaling a bicycle on level ground is really not difficult, so having electric assist on that terrain is sort of pointless.

A 250w mid-drive with torque and cadence sensing that routes power through the bike's gearing would turn the rear tire with a lot more muscle. With that design, PAS is worthwhile. But, it's much heavier with considerable mechanical and electronic complexity, and several times the cost of a geared hub.

 

[Ann M.]

harryS, Leeds has other hub motor systems with variable speed throttles if that's really what you need.