Thanks so much for all this great informating, Im going to purchase the ebook for sure! One small question first, though. I’m building a 13s8p 18650 pack from laptop batteries for my bfang 750w 25A pedicab. I already have 45V 15 Ah LiPo setups from china, but want to up my Ah.
Amazing article, just what I needed. Have been doing LOTS of research but have struggled to find any real answers on which charger I should buy for my homemade battery. I am making a 48V 13s4p battery with a BMS (with balancing) like yours but am stuck as to whether I need to buy a normal bulk charger or a ‘smart charger’ that will balance the battery. My question is will the BMS balance the battery on its own or will I need to get a charger that balances also?
Hello Court! I have spent a good deal of time the past few months researching e-bikes. I read your introductory book and nearly every online review you have written over the last year or so. The closest e-bike shops to me are about a two hour drive and are limited in what brands and models they stock (mainly city style bikes). So before I venture out to test drive a few models, I am seeking your advice to narrow down the type of bike and drive train that makes the most sense for my application.
Hey Barry! I really like the Haibike and Specialized models, both offer great quality and have several sizing options. I agree that mid-drive tends to perform better for climbing and offers more efficiency overall but most of the pre-built bikes are limited to 250 or 350 watts and top out at ~20 mph unless you get one of the speed pedelecs like the Haibike XDURO Race or Focus Aventura Impulse Speed. One alternative would be to purchase a kit like the Lectric Cycles e-RAD 500 which is a mid-drive with shift sensing, throttle and a max speed of ~30 mph if you unlock it for off-road use. This ebike kit can be pre-installed on an Electra or Origin 8 or you can have a local shop add it to a bicycle you already own. One drawback here is messier wires but the price tends to be lower and they can even adapt it to fat bikes and other frame types like cargo or cruiser if you want.
China’s experience, as the leading e-bike world market, has raised concerns about road traffic safety and several cities have considered banning them from bicycle lanes. As the number of e-bikes increased and more powerful motors are used, capable of reaching up to 30 miles per hour (48 km/h), the number of traffic accidents have risen significantly in China. E-bike riders are more likely than a car driver to be killed or injured in a collision, and because e-bikers use conventional bicycle lanes they mix with slower-moving bicycles and pedestrians, increasing the risk of traffic collisions.
The Electron Wheel fits most bikes with rim brakes, and doesn’t need any wires or throttles to operate. Just use your bike like you always have, but enjoy the ease of a pedal assist experience. You’ll be hooked after experiencing how the wheel neutralizes most hills and allows you to commute without breaking a sweat.
First of all, NCR18650B cells cannot be discharged at 2C. Those are 5A MAX cells, and really you should keep them closer to 1C to keep them cool and happy. They are economical cells. They do better when in large parallel groups so you can take advantage of their high capacity without the downside of their low discharge rate. They are great cells, but not for low AH packs.
You may have missed the point – I’m considering both front and rear motors together – 1,000W DD in the back (I figure there will be less wear and tear given the action in the looses sand) and a 350W geared motor in the front. They would be on separate throttles and the front motor would only be used very occasionally – if and when the back wheel really digs in. The rider’s pedaling is by way of assistance to the rear motor.My reluctance to deploy a BBS02 is based on:
I figured this would be a critical step I wouldn’t want to mess up. Thanks for the advice on using the multimeter. That’s batteries electric bikes to know as I thought I might need to open up the controller and see which wires went where on that male xlr connection which I guess would be an option too. Thanks again!
I would advise against connecting one battery to the other’s charging port. That charging port, as you correctly stated, is wired to a charging circuit on the BMS which is usually meant to take 5A max, sometimes less, whereas the discharging side of the BMS usually puts out at least 15A, sometimes much more. You can easily fry your BMS by connecting a second battery to its charge port.
Hi Court, great site and appreciate your insight, and obvious care. I am also ebike noobie, but have been doing my homework (hours of googling). Personal specs are, old guy, out of shape (5′ 10″ 270# but physically intact), looking to “upgrade” self. I am a mechanic for living, so nothing technical worries me. You have done great job of laying out the general parameters and options, so now I “get” that, and have evolved to the confused info overload stage. Application would be recreational/touring, hills/long grades are always in play, some trail riding, but no serious mountain biking at all. Range not so much a big deal, and plan to “pedal” for the exercise, assist would be for hills, and overextending (needing a lift back to the barn). Issues for me are quality/durability, and rider stability including push off and simple shifting (as opposed to complicated timing and planning routines). I may also see a fair amount of urban stop and go when vacationing etc.I don’t see myself speeding along at 30mph (scares the bejeebers out of me to even think about that speed on a bike). Lots of questions, but will focus on one … It seems like most of the issues (other than battery, range, regeneration and such) revolve around drive train concerns. I like the idea of the mid-mount, but am concerned about the shifting and stress on chain etc. Can a quality mid-mount add on kit, easily work with an internal shifting rear hub. The idea being simplicity…no front shifter, single cog, and easy rear shifting (especially when stopped, or going slow). I am a little confused over the internal geared options, seems like several methods Including external gear set for more increments). Problem may be the shifting while motor engaged. But I believe the internal shifting (similar to the old 3-speed bikes) can be done while pedaling or not, so likewise would not be affected by motor load. If true, that reduces the need(benefit?) of a motor disengage feedback when shifting. This setup also seems like it would benefit from a torque(? not sure I understand this) aware feedback mechanism (seems cadence ones are not really so great) for the “assist” with a few selectable assist modes. If not applied to an external geared internal hub, then only 2 cogs now, and perhaps can use the gates belt system, which seems like a good (dependable) upgrade (not sure how well gates deals with hard shifts if that is a concern). Anyways, hopefully I have asked a reasonable (as opposed to ridiculous!!) application question. If viable, could you suggest the actual brands/models you would use? Thx again.
I’d recommend going with a cell that can output 10A, giving you 40A continuous power rating. You’ll use less than that, meaning the cells will be happier (and cooler). Something like the Sanyo 18650GA or LG MJ1 would give you good power and capacity (both are around 3,400 mAH per cell).