I was planning this for bike bottom bracket and crank setup but would work the same with a board and Im trying to get confirmation on the electronics
If I were to use a 3-phase motor/generator in a skate wheel with a super low kv that produced 100v even with a slight push, can I connect it through a rectifier and caps directly to the battery?
The battery would be max 90v so a resistance would be formed with the relatively lower voltage battery and current would flow. I believe the much higher voltage of the generated current isn’t a problem and only current is relevant
I think imagining pushing an eskate while holding the breaks is going to be pretty close to the experience trying to push charge. Friction and traction and inertia are all going to make for a horrible experience unless coasting down hill where the lack of control could become an issue too. A vesc regen is going to have a similar output for charging current too and just like with regen it’s probably not going to amount to much even when coasting down big steep hills.
Other than the reduced control and lack of the specific charging characteristics which im assuming you would be supplying via a charge controller after the dc is provided to the battery. Might be possible to implement an mppt charger controller to help improve efficiency but at that voltage you may need to design your own
Yea it’s not really wanted while on a board but was hoping someone could tell more about the simple electronics and whether winding to like 1kv, and producing a very high voltage, would be a simple way to do it going directly from the generator, through the 3-phase rectifier, to the battery. Probably not very efficient but would it work?
Can capacitors smoothen the resistance on the generator side (side if pedal) or would it need many magnet pairs to do that?
The caps are gonna smooth the dc on the rectifier output but you can get better rectifiers that output a smoothed dc already. If you’re rectifier design incorporates cleaning up the dc output already you won’t need additional caps. Google around more advanced rectifier designs or look for one that has a tighter ripple spec but really you should pick your charging circuit and find its dc input preferences and design accordingly. Not an engineer just a pretengineer
Might be able to modify a regular ac charger by duplicating the rectifier circuit to accommodate 3 phase input. Might be easier than starting from scratch
If all you’re doing is charging batteries my guess is no capacitor smoothing is necessary. You just need to push more electronics in than want to come out.
I think the answer to your original question is yes, but 100v at a “slight push” would require a very forceful push indeed.
Somewhere out on the interwebs is a discussion of how much power a human being can generate at continuous output and I think it’s less than a 100w
So then divide your battery’s capacity in watt hours by 100 and that will give you how many hours you have to pedal. Then add 25% for conversion and heat losses.
The downside I think to regen is that the boards don’t really regen unless you are actively braking (correct me if I’m wrong), and for you to be actively braking the hill has to be pretty steep.
I have a run I do every summer, it’s a constant climb for 10 miles. I start at 100%, when I get to the top I’m somewhere around 56%. Then I come all the way back down and I’m usually at 57% Maybe 58
This is my unverified understanding as well, people are efficient at walking not powerful at it. Ive briefly looked into human powered generating power for backpacking stuff and the amount of work for the payoff is almost always mathing to extra batteries are lighter to carry than the infrastructure to charge them with less hassle.
Even newer solar setups maximizing the amount of charging per gram by eliminating every extra gram making setups very fragile and assuming perfect light exposure work out to be more weight than the weight of batteries until about 8-10 days of travel with high usage rates like old gps and sat communication devices in heavy use let alone a means of transportation which is orders of magnitude more. Then there is the time spent setting up and charging where you have to dedicate effort to charging instead of your other goals.
From a prepper perspective solar is going to be smaller and more efficient per calorie of effort as well as requiring less direct effort. A solar panel on your deck (or bike frame) that is charging a pack will likely be smaller and more effective to passively add a couple wh of charge to a pack or bank. If you made a super efficient bike or board you might be able to do something interesting this would also be best for any people powered generation too
Funny story, a long time ago I was surfing the web and I ran across this post about how a motorhome maker was going to add solar panels to their motorhome that would give you infinite range.
I of course posted that wasn’t going to happen but I got a response where the guy actually said that they’d been making motorhomes for a really long time and surely knew what they were doing.
electricity takes a lot of human effort to make but I’m freezing riding around on this bike as the pedals don’t do anything and it was either add non-Newtonian fluid to the bottom bracket bearings or do this. Adding the generator n rectifier seems easy enough. I just hope I can get enough resistance from a motor the size of a bottom bracket with like 2kv.
If your primary mission isn’t avoiding overvoltage, undervoltage, and overcurrent conditions then this seems extraordinarily dangerous. Possible? Yes. Practical? Not really, depending on your ability to create safe circuitry.
I think ur thinking i would do something else. This would just be a small super low kv generator connected to the battery through a three phase rectifier. And a fuse. If the generator put out 90 to maybe even hundreds of volts, then converted to a lumpy dc, then to the battery… what’s bad? The current would be very small.
If you don’t stop the charge when the lithium ion battery is full, any reasonably nonzero charge current can cause major problems, even if it’s small, given enough time.
Rivian is certainly aware of this and definitely has electrical engineering staff ensuring this isn’t happening.
Just don’t pedal when the battery is full. Could maybe even run the generator output through the bms. But simply not pedaling a lot when the bike is stationary seems adequate
As I understand it you can’t “under voltage” it. It’s a generator and it won’t produce any current that would go to the battery if it’s not producing a voltage higher than the battery. It also doesn’t take voltage away from the battery through the diodes of the rectifier
The point would be to over-voltage as that’s the only time it’s going to produce a current that could charge the battery.
By over-current it seems you mean a short as I’m not able to pedal hard enough to produce more than max maybe 1000 watts for seconds and the battery is fine with that
If anyone has a specific way u can imagine how a fire could start doing as I write please tell? @BenjaminF
this would also be best for any people powered generation too
