How to design a turbo boost

[Chalo]

I have a 55 T largest chain ring + a 11 T chainring on the free wheel. Trying it pedal it without the motor on the highest rings would be excruciating lol.

Running in the 11t for very much of the time will be excruciating to your chain and sprockets. The only reason 11t works on pedal bikes is because you spend so little time using it.

On the other hand, ghost (make-believe) pedaling isn't too hard on your drivetrain. But you can easily consume more energy as increased drag from your legs stirring the air flow than you add by pedaling.

 

[DogDipstick]

I can tell you how they did this in Circa year 1900. When they needed an equivalent of this, " trbo powa" you speak of.

Its not a new concept.

into the weeds with new big ideas, maybe spen

just run a 72v system and raise the level when you want to go faster?

This is pretty much how they did it.: Way back then.

With cell end connections. Switching. Voltage goes lower, Operator connect(s) another cell. On and on, and so forth.. Keeping voltage at the desired level. For the load. Then they designed some cool automated systems to do this too: in some power houses and DC generation systems.





i was thinking bout it. Just today as I was playing with a Arduino. Conceptually.

Like a throttle, action, that increased the voltage, of the system, linearly, with the load, on the motor.

PLC and PID A/D converter inputs and... shit.



On the aside:


55/11?

Wouldnt the same link, hit the same spot, on the same sprocket, every time (time measured in revolutions, minutes per... ) ?

........the issue isn't odd versus even... it is that the ratio is an integer (5).

Hmm. IDK.

 

[DrkAngel]

Somewhere past 20mph, wind resistance in proper pedaling stance is more of a detriment than sustainable pedal assist can compensate for.
Near 30mph it requires 250w pedal assist to match benefit of tuck position on a mtb. Same pedal effort as sustaining 18mph.



Add 250w "Human power" to "system B" to verify Motor Simulator
Play with "human power" to gauge pedal assist near 30mph.

 

[Chalo]

I can tell you how they did this in Circa year 1900. When they needed an equivalent of this, " trbo powa" you speak of.

Its not a new concept.

Yeah, but they weren't doing it with BLDC motors. That sort of changes the feasibility.

I have seen such trickery-- effective or not I don't know-- employed on cheap assed Unite brushed motor scooters and the like. PWM controller plus a bypass circuit straight to the battery.

120 years ago, they weren't using PWM. I guess they were unbalancing their battery packs on purpose by the method you described.

I still want to see the results of Mark J connecting a BLDC motor directly to the battery in pursuit of turbosity.

EDIT:

Ah, I see you're responding to the new revised original post. His original original post said he wanted to juice the motor by bypassing the controller and connecting it directly to the battery. I guess he figured out how stupid that would be, and changed the top post without noting what it originally said. That means a lot of the discussion that follows (including what I wrote above) doesn't apply to the revised post.

 

[E-HP]

Somewhere past 20mph, wind resistance in proper pedaling stance is more of a detriment than sustainable pedal assist can compensate for.
Near 30mph it requires 250w pedal assist to match benefit of tuck position on a mtb. Same pedal effort as sustaining 18mph.

30mph pa.jpg

Add 250w "Human power" to "system B" to verify Motor Simulator
Play with "human power" to gauge pedal assist near 30mph.

The data appears to indicate that a zero cost, yet effective design of a turbo boost is to start out riding in MTB Upright, and when you want the turbo boost you shift to MTB Tuck :thumb: . On top of the extra speed you get the added bonus of more range .

 

[MarkJohnston]

I have a 55 T largest chain ring + a 11 T chainring on the free wheel. Trying it pedal it without the motor on the highest rings would be excruciating lol.

Running in the 11t for very much of the time will be excruciating to your chain and sprockets. The only reason 11t works on pedal bikes is because you spend so little time using it.

On the other hand, ghost (make-believe) pedaling isn't too hard on your drivetrain. But you can easily consume more energy as increased drag from your legs stirring the air flow than you add by pedaling.

meh, ghost pedaling stinks. yeah i have four 7 speed flywheels. I'll just burn them up. chains are cheap. :lol: i can rarely peddle up with 1000 watts pumping through the motor. 40 mph gets jittery a lil.

 

[DrkAngel]

The data appears to indicate that a zero cost, yet effective design of a turbo boost is to start out riding in MTB Upright, and when you want the turbo boost you shift to MTB Tuck :thumb: . On top of the extra speed you get the added bonus of more range .

Pedal assist is greatly effective at starting speeds, important when you want to beat cars when the light turns green. Even on my 675w 20mph "geared" eBike, often it'll take cars half a block to catch up. Though, click shift might be needed as I shift through 5 speeds in 5 seconds.

While 250w of sustained pedal assist will give you an additional 3mph, to 30mph ...
(800w output motor of above's motor simulation)
The same 250w pedal assist will increase your acceleration:
643% (46w to 296w @ 1mph)
352% (99w to 349w @ 2mph)
276% (145w to 395w @ 3mph)
229% (193w to 443w @ 4mph)
202% (243w to 493w @ 5mph)
186% (291w to 541w @ 6mph)
175% (332w to 582w @ 7mph)
165% (385w to 635w @ 8mph)
157% (435w to 685w @ 9mph)
152% (480w to 730w @ 10mph)
...
134% (728w to 978w @ 20mph)


"Turbo" might be most easily applied via standing start, transitioning to crouching on lowered seat as 20mph threshold is passed.

Please note, also.
Pedal assist can be especially effective as eBike slows on uphill grade!

 

[E-HP]

"Turbo" might be most easily applied via standing start, transitioning to crouching on lowered seat as 20mph threshold is passed.

I believe this transition is what they refer to in the industry as "turbo lag" :lol:

 

[4πr^2]

Hello,

I want to build a small and lightweight but high voltage battery. The point of this battery would be to over volt the motor temporarily to get a ton of speed i.e. 50 mph just for 5 or 10 minutes. ...

bwa ha ha lulz! Sounds like your best bet is to just design a system to go 50mph for 10 minutes. Put a DE-rating switch in it to cut back the power, then flip the switch upside down so 'On' is actually 'Off' and label it 'TURBOZ BOOST!' or 'NOSSS!

This is pretty much done for you if you get a sur ron and put the switch in that wire that everyone talks about cutting.

 

[Chalo]

Running in the 11t for very much of the time will be excruciating to your chain and sprockets. The only reason 11t works on pedal bikes is because you spend so little time using it.

yeah i have four 7 speed flywheels. I'll just burn them up. chains are cheap.

There aren't a lot of 7 speed freewheels available with 11t high gear. The ones I'm aware of are DNP Epoch and are of poor quality.

Just understand that the 11t sprocket wears quickly, then transmits that wear to the chain, which in turn transmits the wear to the other sprockets and the front chainrings. You can get a chain checker and replace chains before they're completely toasted, but that won't reverse the wear on the 11t sprocket that started the cascade.

I have a couple of old Shimano 11-34 freewheels in pedal bikes that have lasted a very long time, but I almost never use the 11t sprocket.

 

[markz]

Which ones wear the least or a good compromise?
12, 13, 14?

There aren't a lot of 7 speed freewheels available with 11t high gear. The ones I'm aware of are DNP Epoch and are of poor quality.

 

[MarkJohnston]

Running in the 11t for very much of the time will be excruciating to your chain and sprockets. The only reason 11t works on pedal bikes is because you spend so little time using it.

yeah i have four 7 speed flywheels. I'll just burn them up. chains are cheap.

There aren't a lot of 7 speed freewheels available with 11t high gear. The ones I'm aware of are DNP Epoch and are of poor quality.

Just understand that the 11t sprocket wears quickly, then transmits that wear to the chain, which in turn transmits the wear to the other sprockets and the front chainrings. You can get a chain checker and replace chains before they're completely toasted, but that won't reverse the wear on the 11t sprocket that started the cascade.

I have a couple of old Shimano 11-34 freewheels in pedal bikes that have lasted a very long time, but I almost never use the 11t sprocket.

mmmm there's a $30 11-34 on ebay. not sure about quality yet. Will let you know

 

[MarkJohnston]

"Turbo" might be most easily applied via standing start, transitioning to crouching on lowered seat as 20mph threshold is passed.

I believe this transition is what they refer to in the industry as "turbo lag" :lol:

I am on a MTB which puts me in a "sport" motorcycle position.

 

[Chalo]

Which ones wear the least or a good compromise?
12, 13, 14?

There aren't a lot of 7 speed freewheels available with 11t high gear. The ones I'm aware of are DNP Epoch and are of poor quality.

Each extra tooth is a significant step up in smoothness and durability. 12t high freewheels haven't been made in quantity for a long time. 13-34 is relatively easy to find, but 14-28 and 14-34 are by far the most common, and the easiest to find in decent quality versions.

None of them are as good as the 11-28 and 11-34 Shimano freewheels made 20 years ago. I think one of the reasons those were discontinued was because Shimano thought they might take sales away from more profitable and captive cassette-freehub systems. It's easier and cheaper to make a strong, light, durable, and slick hub using a threaded freewheel than one using a cassette. The industry hadn't caught on yet, and I suspect Shimano didn't want to help others figure it out by providing a premium quality freewheel.

SunRace makes nice quality e-bike freewheels with 11t high gear, but only in 9 and 10 speed. There's no reason to avoid those, but there is a good reason to avoid using the 11t gear too often.

 

[MarkJohnston]

Ok Im thinking the only way to do this is to get a very high voltage/wattage controller. I would have two controllers the one I have now and one high voltage one mounted underside the rack.

Basically i would have an on/off switch in the wiring in between my batteries already in parallel. the switch would link them up in serial. Then it would be 112 volts 20 amps. I would have two of those small thumb throttles installed, the high voltage controller on the left hand side. The right side just being the regular every day use as not to burn too much battery too quick.

So basically on some of those flat abandoned desert roads you could flip the switch and easily hit 50 mph+. I can't really find such a high voltage/wattage controller though. i wonder if it even exists ... i am sure it must

 

[wineboyrider]

Used to boost my lifepo4 ping batteries with lyens high voltage 9fet and 6fet controllers. Would go from 36v to 88v. Could be done easily with a dpdt switch and the right controller....

 

[cloudy]

SunRace makes nice quality e-bike freewheels with 11t high gear, but only in 9 and 10 speed. There's no reason to avoid those, but there is a good reason to avoid using the 11t gear too often.

Hi Chalo,
I' have a 10speed DNP Epoch Freewheel with the 11t sprocket on it. I like the freewheel but it's a fair bit wider than my 7speed, leaving less room on my DD hub axle for for torque arms and axle Nuts. I don't like having to skimp on torque arms or not having enough thread for the whole axle nut.

Do you know if there's any way to make these freewheels more narrow, such as by removing one of the sprockets? I've removed the lockring on the freehub but then the whole thing just falls apart and there is not enough thread to make it more narrow. Not sure what other options I have, other than going to (horrible) low quality 7 speed shifters and chains. I like the 10 speed XT shifters I have.

 

[Chalo]

I' have a 10speed DNP Epoch Freewheel with the 11t sprocket on it. I like the freewheel but it's a fair bit wider than my 7speed, leaving less room on my DD hub axle for for torque arms and axle Nuts. I don't like having to skimp on torque arms or not having enough thread for the whole axle nut.

Do you know if there's any way to make these freewheels more narrow, such as by removing one of the sprockets?

I don't think there's any feasible way to narrow that freewheel. Removing material from the outside end would remove the lockring thread.

If the splines are the same as a 7 speed DNP freewheel (which is pretty likely), then you may be able to stack 8 (with an additional spacer) or possibly 9 of your sprockets with their 10sp spacers onto the 7 speed body. But then you'd have a crappy DNP 7 speed freewheel body.

 

[E-HP]

I' have a 10speed DNP Epoch Freewheel with the 11t sprocket on it. I like the freewheel but it's a fair bit wider than my 7speed, leaving less room on my DD hub axle for for torque arms and axle Nuts. I don't like having to skimp on torque arms or not having enough thread for the whole axle nut.

Why do you need 10-speeds on a direct drive hub? Buying a 7 speed freewheel seems to be the best way to go.

 

[Chalo]

I' have a 10speed DNP Epoch Freewheel with the 11t sprocket on it. I like the freewheel but it's a fair bit wider than my 7speed, leaving less room on my DD hub axle for for torque arms and axle Nuts. I don't like having to skimp on torque arms or not having enough thread for the whole axle nut.

Why do you need 10-speeds on a direct drive hub? Buying a 7 speed freewheel seems to be the best way to go.

He thinks 7 speed shifters were never good, I guess.

Me, I'd rather use even a cheap nasty 7 speed shifter that always works than a 10 speed one that needs constant attention. 6-speed Deore XT thumbshifters and a 6-speed 14-34 freewheel, even better. I see 6-speed bikes that have had no mechanical work for 35 years, chain and sprockets completely worn out, derailleur hanger bent, and they still index perfectly.

His point remains that 7 speed freewheels are mostly crap. At least Sunrace 8, 9, and 10 speed e-bike freewheels are pretty nice. I wouldn't trust anything made by DNP based on the freewheels I've seen so far.

 

[markz]

"Turbo Boost"

In case you are late.
:lol:

You should go to Spain, learn to slow down a bit, learn the Spanish walk, 0.5mph. Valencia was nice.

 

[cloudy]

Thanks for the replies,

Back when 7 speed was top of the range, it was excellent no doubt. I've seen 8 speed shifters surviving through the ages and I like how serviceable and free of plastic they were. The reason I was keen to go the 10 speed freewheel was I had an existing groupset and none of the nicer 7 speed things. The new 7 speed shifters I've seen were fairly nasty and I haven't really been able to source any of the older ones. Rare like hens teeth.

Chalo, I like your idea of trying to stack the 10 speed sprockets onto a narrower freehub. Means I need to buy another DNP freehub, one day I'll discover how bad they really are.

 

[MarkJohnston]

Used to boost my lifepo4 ping batteries with lyens high voltage 9fet and 6fet controllers. Would go from 36v to 88v. Could be done easily with a dpdt switch and the right controller....

Can you point me where to get one of those controllers?

 

[wineboyrider]

Do a search for lyen any voltage controller. Not online much here any more.