Search results

Date Relevance Most replies

  1. eP

    2 brushed motors 1 controller with "Turbo" button

    So once again i have to ask the previous question: how much really you want to spen on batteries ? Is that really good choice to go to mid 60's % inefficient second drive system to save $100 ?
  2. eP

    2 brushed motors 1 controller with "Turbo" button

    What do you mean by high performance ? High power in and high heat dissipation ? If you start with high 70's motor efficiency then you end with mid 60's efficiency of whole system i'm afraid. It doesn't mean high performance for me. So are you going to use lead acid batts for your setup...
  3. eP

    2 brushed motors 1 controller with "Turbo" button

    Cheap, 80% max. efficient motor is fair enough as the backup IMO. But primary motor should be 86-88% efficient at 1.5 - 2kW power out power level unless you don't want dissipate too much heat. For 80% efficient primary motor you would need a lot of dense gears to keep efficiency at decent...
  4. eP

    Using RC motors on E-bikes [Archive]

    HV RC controllers are expensive for the sake of marketing reasons IMO. They are targeted for niche expensive models which need also expensive motors and batteries. In EV worlds we need much cheaper energy batteries, cheaper motors and more controllers (the same extremly powerful) per vehicle...
  5. eP

    Using RC motors on E-bikes [Archive]

    columns are mph 1,5 etc up to 50 rows are slope % 0, 1 etc up 18 Load datas are from :http://endless-sphere.com/forums/viewtopic.php?f=3&t=3981&p=58768&hilit=watts#p58768 I hope that help :wink: edit That spreadsheet is for advanced users mostly. Anyone can modyfy it , add some...
  6. eP

    Using RC motors on E-bikes [Archive]

    Hi all I've just made a little spreadsheet for right gear ratio choice. Lets look what i've done:
  7. eP

    Using RC motors on E-bikes [Archive]

    It should works out to around 1500 watts i hope :wink:
  8. eP

    Using RC motors on E-bikes [Archive]

    Ok. It could be an issue. But once again 8k rpm limit is still no problem for me. Maybe heavier (rigid) bell could adress the issue ? Are you sure you get the same loss at each stage ? I'm afraid you get higher loss at first (top rpm) stage.
  9. eP

    Using RC motors on E-bikes [Archive]

    So it is case B as i've supposed. But for that case you still can run them in the right way by lowering gear ratio. As a result you get higher speed range for the same voltage and higher total load adequate for pair of them (to heavy for single one BTW)
  10. eP

    Using RC motors on E-bikes [Archive]

    I don't know why inrunners are better then outrunners in bumpy environment. But i'm afraid high gear ratio gearbox for inruners will not be very efficient too. If i'm wrong let me know such efficient reducer from 20k+ rpm to 200 rpm. It depent on battery prices i suppose. Keep in mind the ESC...
  11. eP

    Using RC motors on E-bikes [Archive]

    If someone don't want wait so he/she could start with less powerful but avalable now ESCs (at decent prices). But if more folks would be interested in this option than cheap homemade ECS is the same way possible in near future as Gary's BMS. That is much easier manageable than decent homemade...
  12. eP

    Using RC motors on E-bikes [Archive]

    I don't think so. If you need really extreme high power - each one choice is very expensive as thay are all niche targeted expensive products. But if we are going to two motor setup than we are much wider options spectrum. And many choices are really money effective. For mainstream products...
  13. eP

    Using RC motors on E-bikes [Archive]

    So lets back to the numbers. What is the cost of Matt's Predator ? What would be the cost of two (40 mm class ) equivalents in power ? The same questions are valid for ESC too.
  14. eP

    Using RC motors on E-bikes [Archive]

    I don't propose two motor setup for the sake of small diameter or weight. Two motor setup is the best choice if someone want avoid super duper 200A amps ESC or the same level expensive 5-6 kW large outrunner. Each one smaller motor is enough efficient for such case (two motor setup). And you...
  15. eP

    Using RC motors on E-bikes [Archive]

    You could buy more watts (for motors and ESC) for the same buks. Two motors are able to dissipate more heat than single one as they have more surface (i assume they are both the same level efficient). In shortest words two motor setup is for people whos want more (power/speed/acceleration).
  16. eP

    Using RC motors on E-bikes [Archive]

    One gear for each one ? :wink: Edit Keep in mind Miles two motor setup is intrisically more powerfull than single motor one. And more power available means less gears we need (smaller span at least).
  17. eP

    Using RC motors on E-bikes [Archive]

    Minimum number of motors could mean maximum number of gears, so it may be not an optimal choice. Especially if these gears are based on manual switching. Two motors could give us more flexibility then 3 gears.
  18. eP

    Using RC motors on E-bikes [Archive]

    It is not the matter of application kind. It is the matter of gear ratio and load level. Let me explain. Let assume case A: one motor setup - overloaded motor 70% efficient (for the sake of heavy overloading) and two motor setup as an alternative 85% efficient each one as they are optimaly...
  19. eP

    Using RC motors on E-bikes [Archive]

    Hi Matt I see you have very little electrical background. The 25% power max gain for double motor setup could be the true only for very deep gear ratio (very high rpm = high Fe_loss to Cu_loss ratio) and too small battery (relatively high voltage sag at power max). So if you want to double your...
  20. eP

    Using RC motors on E-bikes [Archive]

    I didn't said i was the first with this idea (who discovered that). I've only said i was tried to talk here about that idea one year ago. Now i see more and more people like that idea too. :D Motors for masses should be cheaper and cheaper along the time. If upgrade cost would be pretty low...
  21. eP

    Using RC motors on E-bikes [Archive]

    This is true if such cheap motor is unable to work reliable at high rpm. For example motor kv=500, rm(hot)=80mohm, @16V 100A will work this way @4000 rpm. If it could work fine @14 000 rpm at heavy load then as a result you could get much higher efficiency if powered @32V 50A.
  22. eP

    Using RC motors on E-bikes [Archive]

    This is exactly mine one year old idea :) Modular system - one relatively cheap motor for light load (200W cont. 800W peak) for masses, next one for high climbing or high speed for enthusiasts. Best regards
  23. eP

    Using RC motors on E-bikes [Archive]

    Above 2 kW Pout max 2 gears are sufficient up to 40 mph at very moderate span 200%. Above 1kW Pout max 2 gears are sufficient up to 25 mph at 250% span. 3 gears are needed below 1 kW for very special needs excluding racing purposes ( many gears wanted by safe ). Along with time cells would...
  24. eP

    Using RC motors on E-bikes [Archive]

    Good news :) So tell us Matt what is your iddle current for given rpm for all stages.
  25. eP

    Using RC motors on E-bikes [Archive]

    If you are limited to 300W than 500% span may not be enough for you. But at 1500W power out level 250% span is more than enough i'm sure. Show us what is the advantage of 1500W limited motor with 300% span geared hub over 2500W motor with 2 gears at 200% span. Is your 300% span hub allow for...
Back
Top