Rans Stratus - Recumbent

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Terhathum   1 µW

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Rans Stratus - Recumbent

Post by Terhathum » Apr 10 2021 10:31am

I have a Rans Stratus LWB recumbent that I intend to convert to electric.
My plan is to add a 20" hub motor to the front fork. I am considering the Crystalite H3548F Motor.
I'd like to have the ability to go 60 kph / 40 mph on level ground and be able to travel 50 kilometers / 30+ miles on a charge. I will rarely go that fast, but, I want to have the option.
I'm not planning to do any work on the existing drivetrain or rear end.
Both front and rear wheels have v-brakes. However, front fork is steel and I am considering welding on a flange for addition of a disc brake. Any thoughts on adding a disc in the front?
I live in Wisconsin, so, we get snow and parts of the state are hilly.
I'd like to keep my setup cost, excluding battery, less than $1k.

Seeking recommendations for 20" front hub motor. Battery advice? Any general advice is also welcomed.

Thanks!
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neptronix   100 GW

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Re: Rans Stratus - Recumbent

Post by neptronix » Apr 10 2021 12:23pm

I'd strongly recommend not going with a front motor, as ~80% of your weight is on the rear wheel. You will have severe issues with traction and funny steering on a bike with this design.

Go rear, and try out a leafmotor 35mm "1500w" motor ( closer to 2000w rated in reality ).

ps.. front disc brakes won't benefit you much because the 20" front wheel rotates quicker and therefore brakes better on the vbrake pads. But you don't want a ton of braking force up front.. because you do not have much traction up front.
Regen in a rear hub can be tuned to be very strong.. even in a 26" wheel. You have a lot of your weight sitting on that rear, so that's a good place to have strong braking.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500 MTB.
Monster MTB: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: Heavy duty Cannondale semi recumbent - under construction.
Blue Dream: Maxaraya FS semi recumbent and high efficiency mid-drive - under construction.

donn   10 kW

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Re: Rans Stratus - Recumbent

Post by donn » Apr 10 2021 2:10pm

What neptronix recommends there is just about exactly what I did with my old Ryan Vanguard, and it ran pretty well. Except I left the regen configured to the the usual modest force.

Then I moved the motor to a Burley Limbo, because the Vanguard is such a fine classic ride on its own, and at the higher average speed I really love the Limbo's rear suspension. When I say higher speed, though, I'm just talking about averaging maybe 14mph and very rarely exceeding 20mph, maybe occasionally hit 30mph on a big downhill or some kind of desperate highway situation. Riding like that, of course it doesn't make much sense to set up a system that can make 40mph, though you might be able to get the Leaf up to pretty near 60kph. Especially if you can minimize wind resistance. You won't be able to make it really roadworthy at that kind of speed, in my opinion, but that's up to you.

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dequinox   10 kW

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Re: Rans Stratus - Recumbent

Post by dequinox » Apr 10 2021 2:43pm

You could probably get a BBSO2 to work on this, but I'm with donn and neptronix on this one. A rear hub won't significantly change the center of gravity for which the bike was designed. Put a hailong style battery between your knees and you're all set.
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Terhathum   1 µW

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Re: Rans Stratus - Recumbent

Post by Terhathum » Apr 11 2021 12:52am

Donn, Neptronix and Dquinox - thanks for weighing in! The rear hub seems like a better bet. I'll post a follow up pic, and a few lines about how the project rides, sometime over the next few weeks.

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neptronix   100 GW

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Re: Rans Stratus - Recumbent

Post by neptronix » Apr 12 2021 3:52pm

..honestly another aspect to consider is that without rear suspension, you're gonna have a bad time. I'd aim for a slower top speed. More like 30mph.

..at that point, the leaf 35mm is overkill.
The Shengyi SX2 or a 30mm DD starts to look a lot better at that point.
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500 MTB.
Monster MTB: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: Heavy duty Cannondale semi recumbent - under construction.
Blue Dream: Maxaraya FS semi recumbent and high efficiency mid-drive - under construction.

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Chalo   100 GW

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Re: Rans Stratus - Recumbent

Post by Chalo » Apr 12 2021 5:30pm

Yeah, not only is 40 mph way too fast for a small wheeled bike that doesn't let you stand up on the pedals, but just having that capability will most likely reduce acceleration, climbing, and overall efficiency when it's operating in a more workable speed range.

I think Leaf 1500W is still a good choice, but only if you pick a motor winding that gives you an unloaded wheel speed of say 30-35 mph or less. That way you can have lots of low end pull, but reach equilibrium at a top speed you might actually want to use.

However, no big direct drive motor like that is a good choice if you plan to pedal the thing unpowered for much of the time. In that case, you want a clutched geared motor like MAC, eZee, or Bafang BPM.
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donn   10 kW

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Re: Rans Stratus - Recumbent

Post by donn » Apr 13 2021 9:35am

I haven't tried this, but Grin's Phaserunner type controllers are supposed to be able to be configured to supply a low base level current that just compensates for the core loss that otherwise makes a direct drive a little unpleasant to pedal unpowered. It costs very little in battery power - empirically, in somewhat hilly terrain maybe less than the direct drive's regenerative braking will get back. So that might be a consideration if you'd be pedaling unpowered to squeeze a lot of miles out of a battery charge. (And not if your battery is dead, and it doesn't do anything about the weight of the motor.) With my Infineon clone, unlike the Phaserunner, I'm essentially controlling the motor voltage/rpms, so I can dial in a low assist level only relative to speed - if I hit a grade and the load goes up, the motor will dutifully draw more power to maintain that speed unless I adjust the throttle - which is fine in general, just not suited to the "electric freewheeling" mode I'm talking about here.

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neptronix   100 GW

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Re: Rans Stratus - Recumbent

Post by neptronix » Apr 16 2021 11:06am

Yes but it costs you 25-100w to 'freewheel pedal', depending on speed, wheel size, and motor choice.

If you do a lot of hilly riding then a DD is a pretty good choice for braking on the way down and recuperating some of the momentum energy.

If you use a 28mm wide 9C clone, commonly sold as a 750w motor, you'll have very minimal magentic drag as you pedal. You'll miss out on some hill climbing torque and efficiency versus a larger 35mm wide motor, but it would be more appropriate for your bike.

Leafbike makes the most efficient rear drive motors i know of, and pedaling my 35mm wide leaf was 'almost doable' indefinitely. I imagine a 28mm wide motor would be pretty decent to pedal sans any controller tricks. :)
"Love and compassion are necessities, not luxuries. Without them, humanity cannot survive." - Dalai Lama

My first major build: 1.6kW 8T MAC motor on a Trek 4500 MTB.
Monster MTB: Leafmotor 1500w @ 4kW on a Turner O2 full suspension.
The monster scooter: Heavy duty Cannondale semi recumbent - under construction.
Blue Dream: Maxaraya FS semi recumbent and high efficiency mid-drive - under construction.

Stu Summer   100 W

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Re: Rans Stratus - Recumbent

Post by Stu Summer » Apr 16 2021 6:19pm

FWIW, my Ryan Vanguard LWBR, has a Mac 5T up front and a small 350-500w cyclone mid chain. Yes, it is heavy! I especially like having two independent drive systems. Having the Mac up front has not hurt the handling at all even at low speed. In fact, I like the feeling of solidity at speed. It handles very well. I typically use both motors starting up, the Cyclone as it can use 1st gear of the drivetrain. The 5T is a fast winding and so I don't like to ask it to get me started on its own and indeed it will not on an uphill. Further, due to the geometry of the bike and to my desired size of my front chain ring (61teeth), I can't easily rig a front derailleur. So my range is limited to a high end. But it works because the two motors and me can get us going on almost any hill and it means I can pedal spin along even at 35 mph. In practice, I rarely go that fast as I don't think it is safe, regardless of my good tires, knowledge of my local roads, awareness of traffic. And because I have rim brakes. (I did go 45 mph down a steep hill but I make that a rare thrill.)

I have thought of putting a BBSHD or BBS02 and may do so when the cyclone dies. That would be a lot of weight up front, maybe too much with the Mac.
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2013 DB Haanjo Commuter with BBSHD and Zzipper fairing
Marin Rift Zone FS with BBSHD
Kysmo "lab" bike with 350w hub motor
Ryan Vanguard recumbent LWB with a 36v Cyclone 350w middrive and a 56v MAC 5t in the front hub.

donn   10 kW

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Re: Rans Stratus - Recumbent

Post by donn » Apr 16 2021 10:28pm

neptronix wrote:
Apr 16 2021 11:06am
Yes but it costs you 25-100w to 'freewheel pedal', depending on speed, wheel size, and motor choice.
That sounds like a pretty poor motor choice. Grin says around 10-30W. I don't have a very good feel for the core loss in mine - it seems to come and go depending on the grade, at grades that all seem pretty flat to me. At any rate, he did claim that in the field, regen more than compensated for the trickle, which I think is the key point. That isn't a whole lot of watt-hours, but whether it is or not, that's your choice - if you want regen, you have to deal with that core loss, until they decide to start putting clutches in the motors.

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Re: Rans Stratus - Recumbent

Post by goatman » Apr 21 2021 10:20pm

virtual electronic freewheeling
if you set it so that the rear wheel unloaded speed is 1 revolution per second, youll coast like a normal bicycle and wh/km is 20 to 25, you dont notice any hit to range

on my stiletto the hs3540 with a 24x3.0 tire, it needs 1.5amps injected, 60v battery= 90 watts
if you get 10% back on regen it makes up for it BUT coasting without the motor braking your momentum once you stop pedaling or releasing the throttle is nice

if youre putting the 3548 in the rear, youll probably want a fatter tire, which is why i changed from 26x2.5 hookworms to a 24x3.0 waaay softer ride at high speeds

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