Postby nutspecial »
Awesome! Wow, you just can't go wrong with a full rolling chassis for 150$. Bicycle brakes, OR a wheel, Or bars and seat are like 150$, EACH lol. Does she weigh about 150lbs before electric?
Thanks for the input, I really don't know either. I'm pretty sure you just want the best balance of volts and amps to get to target wattage, while maintaining a usable reduction. The slower kv motors definitely like alot of volts, but I'm not sure about the >60kv LR types. I'd think you'll be fine with 6-8kw and 40mph. On my bike I just notice the motor starts getting warm in the summer when I'm burning amps but going slow. Never measured the temp, but guessing I back off around 150-170F. It really depends on how you wanna ride- If you're not too hard on it with high amps and low speed, I think the bht would get you moving to 60mph no problem.
I'm planning on gearing down from my current ~40mph topspeed on a heavier build though. For a dualsport maybe not, but for offroad I don't wanna sacrifice the low end performance (and climbing usability) of 0-30mph by gearing higher.
Postby skeetab5780 » Thu Jun 01, 2017 7:48 am
It was actually a complete dirt bike for $100 I got lucky, this is a generic bike you can buy on Amazon for $1500 (best part is I have the engine on craigslist for $150) so when I sell it this will be a wash
And I spend $50 on renthal bars and grips and a #41 chain
Controller is ordered so that's another $235, motor I already owned but I have about $400 into it roughly
I need to buy a scale to weigh it, also need some metal stock to weld my motor mount...hopefully I can grab this stuff today if I have time!
Postby nutspecial » Thu Jun 01, 2017 12:45 pm
Awesome! Alot of times, if you go to the metal supplier (who often also does at least some fabrication), you can ask a -worker- for some offfalls from the dumpster, for a little $. Worked for me the one time I tried, in fact they just gave 'em away. Also, some scrap yards will re-sell metal for pennies on the dollar. I got about 1000lbs of nice I beams, channel, and tube that way.
Ps, I just looked at that controller and it's nice! 300ph amps should be more than enough at 35mph gearing. I was running 200 and when I switched to 24s I turned it down to about 160 iirc- it was a little much. I can't see how many battery amps it supports though to compare with the other controllers. Guessing maybe up to 80a supported? Let us know if/when you find out.
In my understanding the battery amps are the power (combined with the battery voltage). Phase amps are how high of an amperage pulse the controller gives the motor FROM that initial wattage.
///btw, if the bht isn't enough, what do you think of this motor? http://eastgem.net/d7500.html
Looks like it weighs close to 15 lbs, but it does have a faster wind. Would have to hit it with a 24fet (120-140a) to approach 10kw (controller side).
Postby skeetab5780 » Thu Jun 01, 2017 2:58 pm
Hmmm I've never seen this motor before even though I own the d3000w model, they are tiny... This 7500w motor looks pretty nice! Its similar to the Golden Motor 3kw weight but rated at twice the torque and more rpm's!!!
I may have to buy this if the BHT is not enough!
Thanks for the tip that is a good idea, my brother is a welder but he lives like an hour from me. His work may have a pile of scrap that's perfect!
Should be about 120a constant 300a peak, I started a thread for this over in the non ebike section.