Is this possible?

[nsharp]

I'd like to bike commute to work more. I've done it some and enjoy it, but it takes me 50 minutes one way on my recumbent and I rarely do it because it just takes too long. The ride is 10 miles and includes a mile long 400 foot climb on the way in and a 2 mile 600 foot climb on the way home. Some parts of that climb are insanely steep (over 20% grade) and the ride goes through our small downtown, so there are a few stopsigns and lights. It takes 20 minutes by car and my goal is to get the bike ride down to 35 minutes. That would be averaging 17mph total.

Ideally I'd like a pedal assist conversion kit like the bionx or something similar. Does this sound reasonable? Considering the 20mph limit in the USA on most electic bikes, I'm unsure.

 

[flecc]

I very much doubt it's possible with the mainstream motors like the BionX nsharp. However strong a rider you are, the length and steepness of the climbs would drag the average down too much. However, an average of more like 15 mph probably would be possible if you are a fit rider which I guess you are from the conditions you describe.

I think you'd need a more powerful motor to give higher climb speeds to get 17 mph average on that route, the one that springs to mind immediately being the Crystalyte motor. You might need dual batteries to cope with the 20 mile round trip though, since this is a powerful motor which can eat current at quite a rate.

I don't know the US source for this motor, but here's the UK website where you can see it:

Crystalyte motor
.

 

[Tiberius]

Hi nsharp,

You don't say where you are, but you mention the USA 20 mph limit. Most of us on here are in the UK, where the limit is 15 mph.

What you want looks feasible, but its a bit tight in a couple of places, so you would have to be careful with the spec of the bike system.

First the hills sound bad, but then you are pedalling them yourself at the moment and only looking for assistance. Ie, you are expecting the electrics to help you go faster, rather than to do all the work of getting you up.

Second is the overall energy (Watt-hours) for the journey. The combination of the hills and wanting 17 mph average for 70 mins adds up. So one question is can you re-charge at work?

A third point is that you are looking for both hill climbing ability and high speed. Commercially built ebikes tend to be better at one or the other. It should be possible to build one that does both. Or you could optimise the electrics for one function and rely on your own input for the other.

What speed do you get on the recumbent on your own on the flat? if that's high enough, then setting up the electrics for the hill climbing only might work. There's one member on here with a homebuilt e-bent who could advise you.

Nick

 

[Tiberius]

best US source for the Crystalyte is probably www.ebikes.ca Homepage of the revolution

 

[flecc]

Thanks Nick.
.

 

[nsharp]

Hi nsharp,

You don't say where you are, but you mention the USA 20 mph limit. Most of us on here are in the UK, where the limit is 15 mph.

Thanks for the well thought out replies! To answer a few of the questions, yes I am in the USA. Soutwest VA to be precise.

What you want looks feasible, but its a bit tight in a couple of places, so you would have to be careful with the spec of the bike system.

First the hills sound bad, but then you are pedalling them yourself at the moment and only looking for assistance. Ie, you are expecting the electrics to help you go faster, rather than to do all the work of getting you up.

Yes, exactly. In an ideal world I'd just live 20 minutes closer by bike I've looked at the Crystalyte system but it weighs 50-70 pounds and I'd rather just stay with a smaller assist.

Second is the overall energy (Watt-hours) for the journey. The combination of the hills and wanting 17 mph average for 70 mins adds up. So one question is can you re-charge at work?

Charging at work isn't a problem. Since I expect to run the system hard, I'll probably have to either carry the charger or just buy a spare.

A third point is that you are looking for both hill climbing ability and high speed. Commercially built ebikes tend to be better at one or the other. It should be possible to build one that does both. Or you could optimise the electrics for one function and rely on your own input for the other.

What speed do you get on the recumbent on your own on the flat? if that's high enough, then setting up the electrics for the hill climbing only might work.

I can't say that there is all too much in the way of flat ground around here and regardless I haven't measured my speed on the such. All I can say is that my usual average coming home is 12mph which means I need around a 40% increase in my average speed. To be honest I'm a bit doubtful that I can reach the goal, but I'd like to try if I can.

 

[Tiberius]

I've looked at the Crystalyte system but it weighs 50-70 pounds

That sounds like the weight for a whole bike with motor and batteries.

The Crystalyte motor is a bit heavier than others, but then it is higher power. The other big weight is batteries and you'll need those whatever system you use. Battery weight depends on the total Watt-hours and the chemistry you choose.

Nick

 

[john]

You're climb home is 11% for 2 miles. You can't be doing that at more than 6 or 7 mph so you must be going quite fast on the rest of the journey to average 12 mph.

I would suggest therefore looking for help on the hills (more pleasant ride that way too) and rely on pedal power for the rest - downhill (as you say there isn't much flat).

Jeremy had the same issue with weight on his 'bent, so the only motor that springs to mind is the eZee / Suzhou Banfang motor. This is geared for hill climbing torque and has a freewheel for downhill.

 

[nsharp]

You're climb home is 11% for 2 miles. You can't be doing that at more than 6 or 7 mph so you must be going quite fast on the rest of the journey to average 12 mph.

Yup. 6 or 7 is right on. Going down those two hills I have to brake to keep my speed sane. Help up the hills and getting back to speed after stoplights and stop signs is probably where I'll get my best help.

Jeremy had the same issue with weight on his 'bent, so the only motor that springs to mind is the eZee / Suzhou Banfang motor. This is geared for hill climbing torque and has a freewheel for downhill.

I'll check it out, thanks!

 

[Jeremy]

I've converted a SWB USS 'bent, using the Tongxin motor fitted to the 20" front wheel. I originally fitted a Crystalyte 405 motor, with a 48V, 35A controller, but found on a test ride that the weight of the motor adversely affected the bikes handling. My 20" front wheel, complete with Crystalyte 405, weighed about 7kg (15.5 lbs).

The battery pack weight will be the dominant factor, but I've found that the relatively cheap, very light, LiFePO4 packs sold on ebay by Li Ping are excellent.

Although my Tongxin motor is fine, based on the experience of others I don't think I would recommend it. It gives motor assistance up to about 16 to 18mph, which is a bit slow for a 'bent (I cruise around at 20+ mph usually, due to the 'bents low drag and consequent high cruise speed).

I too think that the Ezee/Suzhou Banfang might be your best bet, although I'd be inclined to try and run it at 48V in order to get a decent turn of speed (check out alternative controllers, you don't need to stick with the Ezee controller for this motor). I'd also very strongly recommend Justin at Renaissance Bikes in Vancouver (www.ebikes.ca Homepage of the revolution) as his customer service, level of information and advice he provides and enthusiasm to deliver a good product are second to none.

There are some pictures of my 'bent on another thread here.

Jeremy

 

[flecc]

you don't need to stick with the Ezee controller for this motor

Jeremy

In fact you'd have to have another controller for 48 volts, the eZee controller cuts out at 44 volts maximum, plus or minus 0.5 volts, signalled with 7 LED diagnostic flashes.

I have two bikes with this motor, and I think it's just possible it might match your requirement given the 'bent's inherent speed.
.

 

[nsharp]

Thanks to a great guy at a local bike shop, I got to ride the IZip Street Enlightened from my office to my house. The results? 40 minutes. This is an 8 minute savings (20%) over my recumbent. The distribution is interesting, though - 5 of the 8 minute savings was on the final climb alone. Normally I can climb it in 17 minutes, today it took 12.

Though this isn't as quick as I had hoped, it is promising because there are several mitigating factors:
1) I didn't have clipless pedals - so less efficient.
2) The Enlightened is geared for town use and as such I wasn't able to spin properly while climbing.

 

[nsharp]

Jeremy had the same issue with weight on his 'bent, so the only motor that springs to mind is the eZee / Suzhou Banfang motor. This is geared for hill climbing torque and has a freewheel for downhill.

O.K. Humor me. Searching Google for Suzhou Banfang turns up nothing. Got a link for me? You talking about something like this? eZee Kits

 

[flecc]

O.K. Humor me. Searching Google for Suzhou Banfang turns up nothing. Got a link for me? You talking about something like this? eZee Kits

That isn't the one that we generally refer to, which is the one used on the Torq and Quando. That one's gross power is 576 watts on 36 volts.

This kit one is more like the motor used on the F series eZee bikes and is normally more powerful when sold in the US market, peak gross power of about 680 watts on 36 volts. Ebikes.ca will be able to confirm it's power to make sure.
As usual though I see the eZee controller is limited to 44 volts max as I previously mentioned so you'd need to change that for 48 volts. They say the Crystalyte controller is ok for it.
.

 

[john]

O.K. Humor me. Searching Google for Suzhou Banfang turns up nothing. Got a link for me? You talking about something like this? eZee Kits

Have a look in this thread http://www.pedelecs.co.uk/forum/electric-bicycles/1936-bought-conversion-set-what-motor-controller.html for some information and supply options.

Sorry, the spelling should have been "Suzhou Bafang".

 

[kraeuterbutter]

so you mean this is the motor i have..
can you say how these Suzhou Bafang - motor
compares to other brands ?

i choose it because:
1.) cheap price
2.) Austrian seller
3.) a geard hub-motor, with small size and light weight
4.) free spinning

most important for me: 3.) and 4.)

so: how does this motor compare to other motors on the market ?
what can i expect from it when running with 33Volt ?

 

[flecc]

so you mean this is the motor i have..
can you say how these Suzhou Bafang - motor
compares to other brands ?

i choose it because:
1.) cheap price
2.) Austrian seller
3.) a geard hub-motor, with small size and light weight
4.) free spinning

most important for me: 3.) and 4.)

so: how does this motor compare to other motors on the market ?
what can i expect from it when running with 33Volt ?

It's one of the most powerful for it's size and weight. Depending on the version gross output around 500 to 600 watts on 36 volts.

It will run on 33 volts with a slight reduction in the power, but that wouldn't be practical with the standard eZee controller since that has a low voltage cutoff at 32 volts. I think I saw you illustrate a different controller though, but I can't find the photo now, but that should be ok.

It's only eZee's very small controllers which seem to have such a tight band of permitted voltages.
.

 

[kraeuterbutter]

were i bought they sold it in two versions:
24V and 36V
24V -> shutoff at 17V
36V -> shutoff at 31V
i chose the 24V Version because its the same controller, only programmed with lower cut-off-voltage
so i can use also smaller batteries lying around..
its not problem to use bigger batteries with it, but you have to monitor the voltage of the batts by yourself
from the shop-sayings the controller is able to handle up to 50V