Is this project sheer lunacy?!

[alban]

Hi All
I would like an inexpensive road-legal ebike capable of giving me max help up lesser hills off-road on tracks/bridles predominantly (but some road use) as I am unable to pedal much - and that I can cart about easily in the car. Not interested so much in top speed and range (or looking cool!) - under 10 miles OK. I'm 6' and weigh 100Kgs. This is a tall order I know. I have studied the Tonaro bikes but too expensive and don't fold. Hubs seem to require greater speed to utilise their max power up hills and therefore require more rider input.
From what I've gleaned from reading around here I propose:
Sunlova 20" wheel MTB-type folder with dual susp. Small wheels=mech advantage up hills? Ok for off-road really? Review here Sunlova. Concerned re ruts and doing wheelies tho'!

Fitted with a Cyclone speed limited 1 Chainwheel 24V 250 Watt Ebike Kit as I think legality matters to me and driving through the gears is helpful for hills. I think there is enough space to mount it between bracket and wheel. Clearance from ground is an issue, as is waterproofing I know, but I am a fair-weather cyclist. Using Flecc's figs I reckon I need around 375W to get me (125Kgs inc bike) up a 1:8 at 5mph so at say 80% motor efficiency I'd have to find 470W? - or go slower up the hills, hence the Cyclone idea to provide power and torque at that lower speed. Is it poss that I can get up most hills, up to 1:6, if I'm prepared to go up really slowly?

Using my Cyclamatic (not enough help up hills) 24v 10AH Lipo battery. Connection to it is like a large USA mains type female plug socket (2 blades have to be 2.5cms apart) - puzzling how to fashion a connector as I can't find one anywhere as standard. Some kind of bladed high Amp rated 4-way connector to get the correct dimensions I think. Don't want wires waving around. Ideas?

So cheap at around £380 but am I going to be cheerful? - that is the question. Is it going to be worth the hassle? Is a 20" wheel OK for off-road? Will the Cyclone give me near enough power? (I can't see a max power rating for 250W motor on the website). The max torque reading they give for the 360W is 32 Kgs/cm - doesn't seem much.

 

[NRG]

The Bafang BPM 350 or 500w would be fine in a 26" wheel and get you up most walkable hills. Mounted in the rear wheel fro best traction and fed with a 25amp controller it would be a powerful setup. Use the slower wind 206RPM version and top unloaded speed would be about 16mph @ 26" so you'll get good climbing ability at around 6~8mph. Efficiency drops at this speed at approx 65% worst case so factor that in not 80%.

25amp @ 37v would be 925w minus losses say 100w x .65 would be approx. 540w at the wheel...in reality probably more than this....should be enough

 

[Fordulike]

Using my Cyclamatic (not enough help up hills) 24v 10AH Lipo battery. Connection to it is like a large USA mains type female plug socket (2 blades have to be 2.5cms apart) - puzzling how to fashion a connector as I can't find one anywhere as standard. Some kind of bladed high Amp rated 4-way connector to get the correct dimensions I think. Don't want wires waving around. Ideas?

Think you will find that this is the connector you are after:

Electric Bike Battery - Lithium Conversion Kit | eBay

If you are going to use the Cyclamatic battery to power your project, you need to be aware of a couple of things if you are planning to use a more powerful motor/controller set-up:

• 
  Although the battery is capable of delivering higher amps than the standard Cyclamatic hub motor draws, you will need to replace the 20 amp fuse with a higher rating or they will keep blowing.

• 
  The ignition barrel type lock/on-off switch is not suitable for drawing higher amps through it.
  The solder connections heat up, melt, and the wire disconnects.
  I had to bypass this switch after it would fail on a regular basis.

 

[alban]

NRG - Thanks for the suggestion re the BPM but that would make it road illegal? Are you trying to tell me that I'm on an impossible quest to shift my bulk up hills with any legal setup!!

Fordulike - I might have known you'd be the man to ask about the Cyclamatic battery! I trawled for ages trying to find that item. OK I'll bear in mind the switch melt problem - that's a good heads-up. Cheers.

 

[NRG]

Alban, no it wont be road legal. I mentioned the BPM as you said off-road use...anyhow the Bafang 250w motor can only take so much power the nylon gears being a limiting factor. A more expensive alternative would be an eZee motor from John, legal but capable of handling more power...


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[banbury frank]

Hi We sell a kit which will do your job NO problem BUT not cheap our kits are road legal in low power mode 250 wats electronically restricted to 15 MPH


the bike i recommend is the Dahon Jack £399

Dahon Jack D24 2011 Folding Bike | Evans Cycles


Rear motor kit with 10 ah battery £1250 Fitted to the Dahon bike in Banbury

Best if you come and try one off our bikes with the kit on it we are open 7 days a week




Frank

 

[Scottyf]

I'd just get a 250 watt bafang kit and run a slightly slower wind but then get a larger controller maybe a 30amp max. After all torque increases with amps in a linear fashion.

Either way even a small kit with a small controller can kick out as much as the average rider. I think you'll be surprised even with a standard kit.

 

[alban]

You all seem to be gently steering me away from the Cyclone!
I had abandoned the idea of a legal hub motor because of the lack of power/torque up hills I experienced on the Cyclamatic with its 250W Bafang (plus what I had read here about hubs, max power & hill climbing speeds etc). Not rubbishing the bike, as it was good value. I will probably try the shunt mod to get a bit more out of it - but it won't be enough.

Regarding the legal limit, I read somewhere on here today that the motor power ratings are really 'nominal' in the sense that max power is actually much greater and varies widely among motors. Is it really more about the labelling by the manufacturer then? I see the Cyclone manufacturer supplies '250W labels' to use with all his motors! DIY conversion kits kit Perhaps the 350W Cyclone motor is really 95% the same as the 250W and I shouldn't worry about the nominal legal limit as it will be speed limited and mainly off road. As long as it says 250W then OK as other 'legal' motors push out much more power anyway. The 350W Bafang BPM would be labelled as 350W I presume, so looks illegal.
Even off road on bridles etc there presumably are by-laws that limit bikes to the legal limit or they'd be allowing mopeds?

 

[NRG]

There we where having a nice conversation when yet another flippin' advert pops up!

alban, the Cyclamatic is a bit wheezy when it come to hill climbing. Try the shunt mod, add small amounts of solder to the legs in stages and see how it goes...don't go mad

The 250w Bafang will strip gears at 30amp and is probably best kept to 20amps or less...I've been running my Peugeot conversion at 21amp peak for over a year but I'm very careful not to over stress the motor, so no standing motor only starts and I give as much assistance as possible up hills.

You can hear the motor complain at this amperage and it sounds much better around 15amps...in fact I've recently re-programmed the controller for 18amps max. and knocked back the phase current...its still complains a little but no where near as much as before.

 

[tillson]

Even off road on bridles etc there presumably are by-laws that limit bikes to the legal limit or they'd be allowing mopeds?

Road traffic law applies on Bridleways and Footpaths. The only place that you can legally use a non compliant bike is on private land from which the public are excluded.

 

[alban]

OK - so if I were to go with a powerful hub motor as more reliable than a custom Cyclone kit for off-road hill-climbing then best to get a geared Bafang BPM 500W with:
1. Lowest rpm (highest code?)
2. One for a 26" wheel laced into a 20" wheel for mechanical advantage of small wheel and torque (or too small for off-road? - maybe 24"?)

Will the kit controller automatically speed limit it for Europe?
Any advantage to the Mac motors from Emissions-Free over the Bafang?
Does anyone in Europe sell them in kit form?
Thanks

 

[lemmy]

If its hill climbing you want, couldn't you run to a Panasonic/ Yamaha/ Bosch system?

 

[Scottyf]

The newer 250w models of bafang have better manufactured nylon gears now and people have stopped stripping them.
Also as I said a slower wind in a smaller wheel the torque generated would be more managable for the motor.
You wouln't be anywhere near as stressful as trying to get speed from the motor. It would also still be legal.

Most people on ES whacked alot of volts and amps through the small versions and just cooked them.

anyway...
If it is hill climbing your after then a crank drive is what you ideally need.

My version was just a cheaper, faster fix with parts that are readily avaliable.

 

[alban]

So Scottyf is a 'slower wind' the same as a slower motor rpm?
Problem with hub is worse hill-climbing unless I go >250W but it's reliable and easier to install.
Crank drives - the problem with the Cyclone seems to be reliability/fiddly set up and the with the Tonaro is cost! With health probs I can't afford to break down.

 

[Scottyf]

Sorry maybe I am being incorrect with my terminology.

When I say slower wind it really means a lower rpm per volt electric hub motor.
Each motor as long as it has the same volume of copper in has exactly the same torque and power.

However selecting more coils (Winds) while reducing coil thickness increases the torque while reducing the rpm in a nutshell.
Selecting fewer coils of a higher thickness increases speed.

Both motors have the same power and torque in total but change the power based on a fixed voltage and amperage.