Pedal start with a non-hub r/c outrunner, etc :)

[Desertprep]

While reading posts in this forum I have found a comment repeatedly nested in amongst many jewels of information. I want to write this post to address it specifically.

I have read of several people with non-hub motors saying that they haven't had any problems with their motor/controller/battery setup (can I call this a drive train? or maybe power system?) because they always pedal to get the bike started. If pedaling to get a bike started will keep a system from shorting out, doesn't that mean that the controller has probably not been chosen properly? What is the spike voltage/amperage ( the momentary surge voltage/amperage) required to get 260 pounds of dead weight (rider, bike, batteries, etc) going? and how long is this amount of power needed? Shouldn't the controller be chosen to accommodate that power requirement? as well as the amount of power needed when the rider is cruising along at 15mph and suddenly gives it full throttle? Goldenmotor sells a controller that I have looked at often which is probably a huge amount of overkill. It is 24-72v but with about 300 amps - or 500 for the big brother At 8 pounds or so, it is a heavy sucker, but from what I have read in the posts in this forum and a few others, it seems like it would be a bullet proof solution for an e-bike or e-scooter with an outrunner....as long as hall sensors are installed on the motor. The weight outdoes some of the benefit of using an ourtunner in the first place but there are (in my opinion) a lot of other benefits for not using a hub motor besides the weight. I am not trying to put in a plug for this controller - I know little of it or the company - but rather am setting this out as an example to contrast the thinking used by the "pedal first" folks and open up some discussion. Please feel free to put in a plug for your favorite controller

Edit: Gosh, golden motor even sells a foot controlled "gas pedal" for this puppy - how cool!!!

 

[amberwolf]

I have read of several people with non-hub motors saying that they haven't had any problems with their motor/controller/battery setup (can I call this a drive train? or maybe power system?) because they always pedal to get the bike started. If pedaling to get a bike started will keep a system from shorting out, doesn't that mean that the controller has probably not been chosen properly?

Not necessarily--the reason for pedalling to get started could be simply that their system is only designed as a higher-speed but low-power assist, and isnt' geared to work at lower speeds liek start from stop.

Or, like with my DayGlo Avenger with the 36V 9Ah NiMH pack on there, it could damage the battery to let it pull as much current as teh controller and motor actually need for a start frm stop, so I'd have to pedal as well as motor from a stop.

Also, it could be for range--it takes a LOT of power to start from a complete stop, compared to keeping the bike going at speed once it's there, under about 20-25MPH at least. So to help extend range one can choose to always pedal as well as use motor from a stop.

 

[AussieJester]

The reason people using 'rc' esc's pedal/push off to start is because the controllers are a sensorless controller, you cant give it a fist full from a stand still, however, if you simple push off with a foot before applying power or pedal to start it solves the issues as the motor isin't under load while trying to sync with the controller. Once motor/controller are synced you can pile on the power.

KiM

 

[Desertprep]

...or add hall sensors and then use an ebike controller?

 

[AussieJester]

...or add hall sensors and then use an ebike controller?

Yes.. but its not a off the shelf option and you do sacrifice some efficiency.

KiM

 

[gwhy!]

...or add hall sensors and then use an ebike controller?

Yes.. but ................................. you do sacrifice some efficiency.

KiM

Im not totally sure about that :wink:

 

[AussieJester]

...or add hall sensors and then use an ebike controller?

Yes.. but ................................. you do sacrifice some efficiency.

KiM

Im not totally sure about that :wink:

Explain to us all why Burtie is feverishly working on a device to advane and retard timing in relation to throttle potion? while your at it
perhaps you can also enlighten us on why the guys working with the Astro are also working on rotating hall sensor mount
if it was as simply as strapping halls straight on your motor and getting peak efficiency across the range why are
they making electronically controlled hall sensor brackets that move according to throttle position? Please do tell GWhy.

KiM

 

[gwhy!]

It all depends, how your halls are setup initially KiM, When I was playing with sensorless controllers when I first started The Initial current to get the motor running were much greater than when using a sensored controller and wasn't consistent. I know sensorless controllers tweek the timing throu the rpm range which help efficiency/speed but I think its horses for courses , less startup efficiency or less max rpm efficiency now if Burtie comes up trumps it will be the best of all worlds.

 

[John in CR]

pengyou,

You would need to find out if that Golden Motor big controller can handle the electrical rpm of the RC motor in question. Then there's the issue of hall sensors needed too.

 

[deardancer3]

pengyou; IMHO, starting from a dead stop using just your e-motor is hard on any ebike system, hub motor or chain drive. It is one of the potentially largest peak current draws that a system will see. Hard not just on controlers, but wiring, connections, battery cells and BMS.

Because of this, many of us just get in the habit of a small foot start; that little kick to get up to maybe 3mph may mean the difference between a peak current draw of 30 amps for 5 seconds and 20 amps at 3 seconds. Why go around upgrading everything and adding to expense, when it just requires a little thought? When on an ebike you better be thinking anyway. And even if I could start the bike with no human help, doing this repeatedly shortens the range on the system.

Some may desire to make their systems more bullet proof, while some may just make minor adjustments to their riding style according to what components they have. It is an e-BICYCLE anyway. WE all know that the more we remove limitations on the system, the more it costs.

Observers may think by kicking/pedalling to start, it is more bicycle than moped, more politically correct for those that care about such things.

just my opinions.

d

 

[AussieJester]

Because of this, many of us just get in the habit of a small foot start; that little kick to get up to maybe 3mph

Exactly how i do but less speed haha im classed as a incomplete para so you don't need much forward mojo to stop the jitters as it syncs, it just needs the load taken off and its good to go .. I admit though i often start form dead stop, the new V2 Turnigy i use doesn't seem to clatter and clunk anywhere near as much as my V1 when taking off from standstill for some reason..OH and i am using a V2 hv160 now too that could also be contributor possibly?

KiM