Apologies for jumping around below, might've left info out here and there as JellyBeanThePerfectlyNormalSchmoo has been very unusual and pestering me for attention frequently all day/night; can't really say no to it.
Given the choice, I would prefer solutions that are either open source, or that are supported by open source projects (I realize that there's no such thing as "open source 18650s", but if a controller or BMS does have such option with a good community behind it, I would love to support it. If no such thing exists, it would be nice to support a company that has a good reputation within the community when it comes to support, customer service, repairability, etc. Again, I am referring mostly to things like controllers, BMSs, etc.
There have been OS BMS projects, but I am not sure if any of them are extant, or how many were finished (at least enough to use or further develop). Some that aren't on this forum show up in this search:
but I don't have any info on them, such as this one
www.diyelectriccar.com
and some on Github.
This is the only completed one I know of here on ES
Update 01/11/2021 : Look on our website for latest hardware and updates: www.ennoid.me Hi, I'm looking for an open source BMS (Battery Management System) which would allow me to develop my own electric vehicle lithium-ion battery pack for voltages range from 48V and up to 400V. The problem...
endless-sphere.com
besides the very old Fechter/Goodrum LiFePO4 unit.
Controllers have many OS options; see later in the post for more of that.
Companies with a good rep for all those things I don't know of any. Grin Tech (ebikes.ca) is the best one I know of, but even they drop the ball on support sometimes; nothing they make is open-source but they do actually design some of their own stuff. Their controllers these days are all potted for better reliablity, like the Phaserunner, etc., so not exactly the easiest things to repair. They don't make BMSes (they did make them in their LiGo batteries but those were discontinued because of parts unavailability)....but one of their best most useful products is the Cycle Analyst v3, if you need system monitoring and limiting/etc. Justin_LE (creator of the CA) used a customized version of one to build a "weight shifting controlled" eskateboard, for instance:
Bit of Background: This project is about 9 years coming to fruition. Back at the early days of the UBC electric bike club we go ahold of an Exkate with badly sulfated lead acid batteries, so took it as a project to upgrade with a state-of-the-art (in its day) 'F' cell NiMH pack. After some...
endless-sphere.com
Both the GoPed ESR and the GoQuad will be ridden for fun around the neighborhood (paved). The GoPed might see the occasional "errand", but I won't be relying on either for any type of serious commuting, so I would like to select a battery configuration that favors supplying adequate juice to high performing brushless motors as opposed to longer range (if I also get good range, that would be a nice bonus).
Things that for fun are much easier to do than things that have to be really reliable over long ranges or long times. Usually more expensive, but easier. :lol:
If the riding environment is flat, smooth pavement, then the things that affect performance are weight and torque. Then as you get faster (above 15-20mph especially) the speed you want to go begins affecting it by air resistance since these are anti-aerodynamic things to ride, requiring more and more power to continue accelerating.
On a small system, two motors is often easier to get sufficient torque vs just one higher-power one, but has the disadvantage of added weight and complexity and cost (second controller, etc).
Fair point. I almost included the following sentence in my original post, but removed it in an effort to keep it more concise, I guess I should have included it. Here goes: Right now my main scooter is a GoPed ESR PPV (the one with suspension and the dated, but powerful brushed "Torkinator" motor powered by four large LiPo packs). It will do 27mph on a flat surface (I weigh 180lbs) and 31-32mph downhill. I find the acceleration and top speed to be... meh. Not sure what higher performing electric scooters are capable of doing, I did see a video of someone doing 70mph on one, which I think is insane with such small tires. What is a good, respectable speed range that is easily achievable with today's parts?
You can reach any speed you want if you have the money for the parts that can produce the power, at least if you are willing to carry the battery in a backpack so you can fit the other stuff on the scooter.
So a better question is: what speed do you need it to reach, under your specific riding conditions, terrain, wind/etc., and your riding style?
How fast do you want it to reach those speeds?
How big a budget do you have?
Knowing the first two, stuff can be found that will do it. Then you can decide if it fits in that budget :lol:
Is it reasonable to aim to build a scooter with good (better than Torkinator) acceleration that will do 40-50mph on a flat surface and able to climb the occasional hill reliably, without burning out? I just want to have fun around the neighborhood and have the ability to accelerate up to a good speed every now and then. I hope this helps to give a better idea.
Reliability will depend on the design of the parts--if they are made for *more* power than you will use them for, within the speed range they were meant to supply that power in, then they'll be reliable enough, as that will keep the heat down, which is what kills these things.
If you use parts (including batteries) that are used near their limitations, they'll be less reliable over time than stuff that's never used near it's limits, especially since most of the things you can get in this hobby (?) are built using parts that can barely handle what the things themselves are rated at, if that.
Speed...my questions always start with...do you feel safe on one of these at those speeds? Can you reliably stop very very quickly in unexpected conditions without smearing yourself across the pavement when someone or something suddenly appears in front of you where they cannot simply be avoided? Do they handle and maneuver well at those speeds? Can the tires on them handle those speeds long enough for your usage needs? (tires heat up more the faster they roll, smaller tires means less place for the air to expand into, etc)
FWIW, you can use the motor simulator at ebikes.ca to see what it would take (even with just bike parts) to get up the hills' specific slopes at the speed you'd like to do it at. Then you'll have an idea of the power your system must have to do it, and you can then overbuild it to be sure it would reliably do that.
You can also play with the simulator to see how it works with systems in these situations that are designed for speeds much higher than the hillclimbs would be at, as that changes the available long-term power during the climb.
I touched on that above (the open source/repairability/etc part). Not sure what other features are available.
Well, common feature sets of controllers would be things like displays that allow you to see what's going on (speed, battery info, trip info, power, etc., and change settings without hooking up to the controller, or multiple levels of motor power, control over each of the levels, etc. A few may let you do some of hte other things you mention below.
Other features might include variable Regen braking (vs on/off), either via throttle or a separate braking control, better dual motor control via inter-controller communication, etc.
For the GoQuad, I imagine that a dual motor setup (should that be the chosen route) would require more sophisticated tuning in order to send the right amount of power to each motor depending on conditions/turning, no? For both conversions, it would be nice to be able to do some sort of configuration of the power delivery curve, etc.
VESC has many variations and is probably the most well-supported OS controller.
This forum has a number of OS controller designs like MESC (not related to VESC), some VESC-related designs, some very high power (car-level), some low power (kickscooter / esk8 level), many in between, etc that include software and hardware and control and powerstages, and others that are just software to flash onto commercial controllers like KunTeng and LiShui, etc., and another (Lebowski) that is just a brain chip to run the powerstage of your choice. Most of these are FOC controllers, with better motor control than the typical cheap brushless controllers will have.
For the battery packs, I would love a good BMS that allows me to take good care of the cells, monitor them and extend their life as much as possible. I would be open to build a battery pack from scratch, but if a good company makes quality, pre-built packs that are well received by the community, by all means.
Personally I prefer building with large-format cells from ex-large-EV packs, as those are usually well-matched to each other, and already in good well designed enclosures, and able to handle medium to high currents easily without stress. Places like Batteryhookup are good sources for them, as well as your local junkyard might also have them now and then, or wrecked cars on Craigslist or your local equivalent.
Though I'm sure there are some, I don't know anywhere other than perhaps EM3EV that builds their own packs well with potentially good customer service, etc, but my direct experience with their packs is limited to greater-than-decade-old designs using large-format EV cells. There's numerous threads discussing pack vendors / builders; opinions vary significantly in them.
