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Macosie
13 July 2018, 0715
Though we'll be living in Canada, my wife is Filipino and we have a place in Palawan, Philippines.
I own a Yamaha RS110f which used to carry all three of us (when my kid was little), but now we will need a sidecar to legally move all three of us arojnd the city.
The bike is actually designed and geared to be a tractor for a trike/sidecar rig. It won't be fast but it's practical. Currently, it tops out at 70kmh and with a sidecar it should do 40-50, which is fine for around town.
We have a second property on a dirt road, with a hill and I don't know if my little 110cc will be able to get sidecar up there on its own. So, I was thinking hybrid system to help it out.

Originally, I thought a hub motor on the sidecar would do it, but would the different torques be too much if an issue?

My next thought was creating a 2 wheel drive like on some Ural rigs. Chain drive is on the left side of the bike wheel. A electric motor could be connected to both wheels via drive shafts.

Third option would be dual hub motors with chain drive still on the bike wheel.

Batteries/controller in the side car. ICE on the twist throttle and a thumb throttle for electric, or vice versa for regen.

Use the elmoto for short distances and up the hill. Use ICE when needed. Maybe both if one is not enough.

As you probably can tell, I've no practical EV experience at this point. These are just ideas floating in my head.

I was thinking a 48v system. Would any of these options work?

What do y'all think?





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Stevo
13 July 2018, 1003
I don't think it will turn easily if you put a motor on the sidehack wheel, but a 2 wheel drive on the main bike wheels might be interesting. You also don't want to put a brake on the side wheel.

Depending on what side of the bike the sidehack is on, is how you turn the rig, by accelerating or decelerating. In other words, if the sidecar is on the Rt hand side, when you give it gas, the bike wants to turn right, but if you hit your brakes or decelerate, the bike wants to turn left. The opposite if the sidecar is on the left hand side.

Macosie
14 July 2018, 0041
I have to check on the Ural rig. Both the bike's rear wheel and the sidecar wheel have power. I'm not sure how that affects turning it. Maybe there is slip in the differential?



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Macosie
14 July 2018, 0155
https://youtu.be/Wd4Yav0_U5w

The Ural is a real pig under 2wd, but it's not designed to be engaged all the time, just when needed.

Can hub motors easily freewheel?

If so, then I could potentially set up the 2 hub system to run the 2nd hub only when needed.


Note: a sidecar for the Philippines would be on the right.



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Richard230
14 July 2018, 0602
Ural recommends only using two-wheel drive on their hacks when riding on a loose surface such as dirt or gravel. Trying to use that drive system on pavement results in a vehicle that is almost impossible to turn. The Ural could really use a differential, but that would raise its price noticeably, give one more area of potential failure, something else to maintain and isn't really necessary on paved roads under most conditions.

Macosie
14 July 2018, 2013
That's what I need. I need stability and a torque boost for my steep dirt road.

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Spoonman
16 July 2018, 0250
Hmmm.. in theory I could see this working with the Hub motor on the sidecar wheel alright; but ideally (and perhaps necessarily) the motor itself would have to be an induction or doubly fed machine rather than PM. Reason being that the PM machines will still generate potentially quite a lot of voltage when freewheeling, and could cog; where as the induction machine can freewheel harmlessly.

The theory follows that you spec this "assist motor" to:
A - motor only, no regen
B - set cut in from standing
C - have a fairly low cut out speed
D - be readily overpowered by the main drive wheel so that low speed maneuvers don't suffer from 'solid rear axle' behaviours.

You'll need to have and RPM sensor on the main wheel and control the assist wheel to match rotation.

Macosie
17 July 2018, 2338
You'll need to have and RPM sensor on the main wheel and control the assist wheel to match rotation.

How complicated is this? I like the idea of a lowish speed motor as an assist. I don't know much about induction engines. Mostly what I read about is PM engines. Will have to research.

On the other hand, a hybrid with range extending ice may be possible? If I were to use the pm as primary drive motor while free wheeling the ICE (not sure I can fo that), drain battery, then run off ICE and while freewheel regen charge batteries.

What did you mean by 'cog'?

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frodus
18 July 2018, 0941
Hmmm.. in theory I could see this working with the Hub motor on the sidecar wheel alright; but ideally (and perhaps necessarily) the motor itself would have to be an induction or doubly fed machine rather than PM. Reason being that the PM machines will still generate potentially quite a lot of voltage when freewheeling, and could cog; where as the induction machine can freewheel harmlessly.

The theory follows that you spec this "assist motor" to:
A - motor only, no regen
B - set cut in from standing
C - have a fairly low cut out speed
D - be readily overpowered by the main drive wheel so that low speed maneuvers don't suffer from 'solid rear axle' behaviours.

You'll need to have and RPM sensor on the main wheel and control the assist wheel to match rotation.

Not necessarily true. If the controller is in torque mode, it shouldn't matter. You'd just need to mechanically tie in another throttle so you can control the motor controller. If you push the accelerator, both engine and Controller will increase speed. The controller will not care about RPM, only the torque commanded to it. The more you push, the more torque it puts out. The less you push, the less torque.

Stevo
18 July 2018, 1034
You guys are missin' the point... if you drive the side wheel, the rig will want to go straight. If you wire in some kind of microswitch to the tripleclamps that will cut the side wheel power off when a turn is initiated, that might work. Otherwise, the rig will be difficult if not impossible to turn. That's my experience racing mx sidehacks talkin. Just sayin

Macosie
19 July 2018, 0231
I'm thinking that the 2wheel drive would only work if both wheels are connected. If the bike is on ICE and tge chair us on an electric drive, keeping them synced would be a problem. I could see the sidecar wheel initiating an unwanted turn while I'm climbing up my crappy hill and putting me in the bushes.
Both wheels driving the rig in a straight line is kinda what I need for the hill.



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Spoonman
19 July 2018, 0524
I'm gonna take these in the order they were posted.


How complicated is this?

Incorporating a means of monitoring the RPM on both wheels is easy enough; using that data as a control input for the assist-motor throttle would involve either a programmable microprocessor like an arduino, or a bit of analog circuit design, but would definitely provide the best results. You'd basically wind up installing an ABS rotor on each wheel, these produce pulses of voltage, you then either count the pulses each side and throttle to match (arduino solution), or you time average the voltage and use a differential amplifier to control the output (analog circuit solution). So in total, whilst it's not 'mad skilz' level, there's a bit to it alright.



On the other hand, a hybrid with range extending ice may be possible? If I were to use the pm as primary drive motor while free wheeling the ICE (not sure I can fo that), drain battery, then run off ICE and while freewheel regen charge batteries.


It's an agricultural approach but it could work if you can fit it all in...



What did you mean by 'cog'?


'cog' as in 'cogging'. It's an effect experienced in PM machines where the rotor doesn't spin smoothly, but rather has a 'lumpy' feel to the motion if you were to rotate it by hand. The effect is created by the magnetic forces experienced as the fixed, permanent poles of the rotor pass their current driven counterparts in the stator. Machines which don't have a permanent magnetic field don't suffer from the effect.


Not necessarily true. If the controller is in torque mode, it shouldn't matter. You'd just need to mechanically tie in another throttle so you can control the motor controller. If you push the accelerator, both engine and Controller will increase speed. The controller will not care about RPM, only the torque commanded to it. The more you push, the more torque it puts out. The less you push, the less torque.

Agreed Frodus, if you're happy to operate two throttles simultaneously then you don't need the control feedback from the primary driven wheel, you can just enact the control manually. Definitely an easier approach to implement, although it would take significant practice for an operator to become adept at keeping things smooth.


You guys are missin' the point... if you drive the side wheel, the rig will want to go straight. If you wire in some kind of microswitch to the tripleclamps that will cut the side wheel power off when a turn is initiated, that might work. Otherwise, the rig will be difficult if not impossible to turn. That's my experience racing mx sidehacks talkin. Just sayin

Not missing it - circumventing it. The two standard strategies for avoiding 'solid axle' behaviours between driven wheels are to employ either a differential or independent drive. In the dual throttle implementation Frodus suggests above, you basically drive it like any tracked machine, throttling the inside wheel less than the outside when you want to turn - this conforms to independent drive. In my control based implementation above, one of the prerequisites was that the 'assist motor' should be easily overpowered by the primary motor, this caveat means that the system, even under ostensibly solid axle control strategy, acts more like a limited slip differential arrangement, with the increased torque loading imposed on the assist motor when it is on the inside of a corner serving to limit its influence, and the absence of regen permitting it to freewheel ahead of the primary drive wheel when on the outside of a corner. ;)


I'm thinking that the 2wheel drive would only work if both wheels are connected. If the bike is on ICE and tge chair us on an electric drive, keeping them synced would be a problem. I could see the sidecar wheel initiating an unwanted turn while I'm climbing up my crappy hill and putting me in the bushes.
Both wheels driving the rig in a straight line is kinda what I need for the hill.


The above is correct if you don't have either of the strategies outline above - ie: dual throttle for independent control, or closed loop control which effectively 'connects' the wheels together as you suggest.
The sidecar wheel will only initiate a turn under the former strategy if you throttle it up so as to do so, and it won't initiate a turn in the latter strategy because it is only ever driven to matched RPM with the primary drive wheel.

Stevo
19 July 2018, 0831
Wouldn't a much simpler solution be a hub motor on the front wheel? You would get the benefit of 2 wheel drive without any worries of steering problems.

frodus
19 July 2018, 0850
Agreed Frodus, if you're happy to operate two throttles simultaneously then you don't need the control feedback from the primary driven wheel, you can just enact the control manually. Definitely an easier approach to implement, although it would take significant practice for an operator to become adept at keeping things smooth.


That wasn't really what I was trying to say. You can have them tied to the same mechanical throttle.

But, I didn't recall from earlier, this is a sidecar. So no differential, but a different motor on the outside wheel. Might not work gracefully this way. It would work if the engine/motor were coupled together as a parallel hybrid.

Macosie
19 July 2018, 1116
Wouldn't a much simpler solution be a hub motor on the front wheel? You would get the benefit of 2 wheel drive without any worries of steering problems.

I don't know if I have enough traction on the front wheel to do it, but it is an option I'll consider. I wonder about the feel of driving a front-wheel drive bike?

Macosie
19 July 2018, 1123
Thanks for the detailed response.
I'm not sure about the sensor approach. I think as a first EV application/attempt, it is a bit more than my current skill set.
Nice thing about a sidecar is it can store the batteries, while the ICE remains. The question is whether I would need to replace the swingers to accommodate the chain and hub. That could be solved by Stevo's front hub suggestion.
Dual throttle might work too. I'm thinking I could use thumb throttles, one on each side rather than the twist.

Spoonman
19 July 2018, 1412
You can have them tied to the same mechanical throttle.

I don't expect that would work, you might be able to balance the torque response to throttle with the main drive wheel for one gear ratio on the main engine, but as soon as you'd change gear the two would fall well out of whack. Granted, in the front wheel drive scenario rather than the sidecar scenario, that may not actually cause any significant problems.

As regards the hub motor up front, it's as viable a solution as any of the others, and I don't expect that the traction at the front wheel would be any worse than the traction available to a sidecar wheel.
Also given the nature of the bike, it's not like you're terribly concerned with high speed handling, so there's no penalty to be paid there either.

frodus
19 July 2018, 1423
I don't expect that would work, you might be able to balance the torque response to throttle with the main drive wheel for one gear ratio on the main engine, but as soon as you'd change gear the two would fall well out of whack. Granted, in the front wheel drive scenario rather than the sidecar scenario, that may not actually cause any significant problems.

As regards the hub motor up front, it's as viable a solution as any of the others, and I don't expect that the traction at the front wheel would be any worse than the traction available to a sidecar wheel.
Also given the nature of the bike, it's not like you're terribly concerned with high speed handling, so there's no penalty to be paid there either.

Still not so sure. Hybrids are not widespread, and I imagine it would take some tinkering but I think torque mode (as opposed to speed mode) is a the best choice for this integration.

In Torque mode, throttle 0-100% goes from 0 torque to max torque respectively, not 0- max RPM. It doesn't stabilize at a set RPM based on throttle input. In speed mode, throttle percent = 0 to max RPM, so you can set to a certain RPM and it'll sit there.

The torque you're demanding via Motor controller is going to push as demanded regardless of what gear its in.

Spoonman
20 July 2018, 0332
Yup, that much I understand, and assuming an inline arrangement, there's no problem there - a mismatch in torque between the wheels simply amounts to front to rear drive bias which won't impact on steering. What would, in the axial scenario result in one wheel accelerating faster than the other, in the inline arrangement just means one wheel get's assisted to a lesser or greater degree.

However in axial arrangement, the same method produces a left to right torque bias, which will make the setup a total pig to handle. There's has to be a primary constraint related to RPM for the sake of straight line operation off a single throttle.

Stevo
20 July 2018, 0743
Spoonman and I are on the same page. Yamaha made a 2 wheel drive offroad bike to race Dakar with.http://www.motorcyclespecs.co.za/model/yamaha/yamaha_wr450f%20dakar%2004.htm

Not only is this the best option, I think we can all learn something here if the op goes this route. I've been wondering about 2 wheel drive emc for a while. Just the unsprung weight on the front wheel had me undecided. But on a sidehack, that wont matter so much.

Macosie
21 July 2018, 0131
Lots to ponder here. Thanks everyone.

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