Recent content by eP

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 ?

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...

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...

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...

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...

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

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

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.

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)

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...

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...

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...

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.

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...

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).