hypothetical range question..

muffinman · Jul 31, 2013

ok, taking into account i have no electrical skills, i want to know what the feasibility of this idea is...
if i wanted to travel 100km at about 40-50kmh, on a single charge, assuming no pedal input, approx how large of a battery would i need? what chemistry would be best? just having ideas... if it makes a difference, i was thinking a 9c motor, probably one of the higher torque models. also assume no regen.

wesnewell · Jul 31, 2013

Find out for yourself.
http://www.ebikes.ca/simulator/

muffinman · Jul 31, 2013

i keep trying to figure that thing out... but i have no clue what im looking at 99% of the time. still trying, but no epiphanies yet.

biohazardman · Jul 31, 2013

I get 8-10 miles average out of my 66V 4.6aH a123 20s2p 26650 pack at about 25-30mph with a BMS V2S motor. I only pedal from a start, on the steeper hills and when I want to make it look good. ;^) So converting to your way of measuring things I would need near 30AH of good quality batts to make the 62mile/100km trip in the low 40km hr area with my riding style. Faster speeds mean more batts are needed. This is a rough estimate as many things come into play here. Tire type/pressure, temps, weight, motor efficiency, wind, riding style, hills, road surface ect. all will affect your mileage per AH.

wesnewell · Aug 1, 2013

muffinman said:
i keep trying to figure that thing out... but i have no clue what im looking at 99% of the time. still trying, but no epiphanies yet.

The instructions are right there on the page. You'll need about 1860wh of battery at 40kph on a regular bike. Might as well say 2kwh to be safe. You could cut that in half on a recumbent.

dogman dan · Aug 1, 2013

My non simulator experience on the road would indicate that would be about the minimum for the slower end of the speed range. To go 60 miles on about 1.5kwh, One 36v 20 ah and one 48v 15 ah ping, I had to ride closer to 19 mph, 30 kph. At 40 kph, you'd get about 75k of range. At 50 kph, closer to 50k or less, on 1.5 kwh

So about 3 kwh for 50kph for 100k.

As you can see, the price for 5mph more speed is very steep. Carrying, let alone affording 3kwh of battery is bitch!! Hard enough to carry 1kwh really.

The chemistry won't matter that much, in terms of range. But smaller and lighter will help some if you try to carry 2kwh.

By high torque motor, do you mean a slower winding? The 9c or 9c copy motors in 6x10 need 72v to reach 50kph. Only if you are going to climb extreme steep hills or do excessive stop and go riding does the slow motor make a lot sense for 30 mph travel. You should just get a 9x7, and run it on 48v for that speed, if the hills are 7% grades or less.

muffinman · Aug 1, 2013

thanks for the replies! some good food for thought.

Ariane · Aug 1, 2013

Hi,

Just buy a new Zero motorcycle and you can get the range and perfomance you like to have:wink: Also those motorcycle are really nice looking.

Good day!
Black Arrow

dogman dan · Aug 1, 2013

Well, 30 mph is not that fast. But it does take some energy to go that fast for a really long way. It's totally doable, what he wants.

This is ready for exactly that, 30 mph speed, and 60 mile range. It can carry 3kw of battery no sweat. Now, I just need to find 2kw of free battery and I'm all set. :roll:

As you see, either a trailer or a cargo bike is how you carry that much battery on a bicycle.

Tommy L · Aug 1, 2013

When I travel a 50kph on my Full Suspension (FS) mountain bike, I use 600watts to maintain that speed
and 1200 watts if there is a headwind to maintain that speed.
I average between 25-30watt hours per km. Yes! That would be around a 3kw pack for a approx. 100km of distance traveled.

On my Catrike Tadpole Recumbent trike, yesterday I went 35km at 35kph and used 247 watt hours for 7 watt hours per km.
A big difference in DRAG. The recumbent is way more efficient than an upright bicycle.

This Catrike has a BIONX system on it and I was pedaling hard for a workout. At 7 watt hours per km, I would need just
around 1KW pack for 100km. Remember, it is best to always leave 20% reserve in the pack for longevity

Tommy L sends.....

muffinman · Aug 1, 2013

in reality, id be pedalling as much as i could, and the distance isnt quite 100km. i just like to err on the side of caution. but in this case, that may not be 100 percent feasible

Tommy L · Aug 1, 2013

Long trip and need to be efficient?

muffinman · Aug 1, 2013

lol even get rain protection! but can it handle fat tires?

i guess i should have said cost is the prohibiting factor. also, i would consider dropping speed to 32kmh (thus preventing any legal difficulties)

muffinman · Aug 1, 2013

hey, if anyone knows where i can get a recumbent trike for under $500... lol

cal3thousand · Aug 1, 2013

Buy an electric motorcycle and get the tax savings. Call it a day.

mvly · Aug 1, 2013

It is possible but will cost so much money it would be comparable to getting an electric motorcycle like the zero. Like other have said, just buy the electric motorcycle and you are set.

muffinman · Aug 1, 2013

lol pretty sure the $2500 insurance bill (and that was for a sub 400cc motorcycle) will negate tax savings, plus im not sure how ontario feels about them...

dogman dan · Aug 2, 2013

At 30-32kph, 100 k range is pretty easy, about 1.5 kwh is enough. At that speed, pedaling input actually matters.

Example, at 20 mph you need about 400-500w average, unless you are riding the poster child for drag, my longtail. It needs 600w to go 20. :roll:

Anyway, if you are running 400-500w, your 100w of pedaling is 20-25% of the total. That's a good range extension for pedaling at that speed. With a good 5 amp charger, you can put 300 wh into a battery during a lunch break in the ride too. That makes carrying just 1 kwh a possibility if you aren't in a big hurry. That's 48v 20 ah.

But ride 30 mph, using 1000w, and now your pedaling is only 10% of the total.

Joseph C. · Aug 2, 2013

The biggest problem is weight. I'd go with Lithium NMC. You could get almost one KW/hr in the bike triangle at 6.5kg and you could stick another KW/hr on a carrier bringing your total to 13kg of battery.

2KW/hr would allow you to comfortably travel 100km at 32kph (what Dogman suggested) but would give you a healthy reserve. You could probably make that distance going at 35kph.

Looking at Cellman's site that (1.86KW/hr) would come to US$1,375 before chargers, shipping and Paypal fees.

Want to go faster and get the 3KW/hr and you have a logistical problem of where to put all that battery. 32kg is a lot of extra weight on an ordinary bicycle. A Yuba Mundo cargo bike would take all that battery no problem though.

Tommy L · Aug 2, 2013

muffinman said:
lol pretty sure the $2500 insurance bill (and that was for a sub 400cc motorcycle) will negate tax savings, plus im not sure how ontario feels about them...

I pay around 450 a year in Ontario for each of my motorcycles. One is a 1985 Honda Shadow VT1100C and the other is a 2003 Honda VTX1800C.
I called my insurance company about a ZERO and the rate was $208 for the year, but the Zero is also considered to be 125 to 250cc equivalent.

cal3thousand said:
Buy an electric motorcycle and get the tax savings. Call it a day.

These are good words of wisdom for sure! But if you like to Toy with your Toys, then build something, learn about it while possibly costing
you lots of money testing and possibly making mistakes and ruining controllers, chargers, cells/batteries etc...

If not.....Get a Zero and your good!

Tommy L sends.....

winkinatcha · Aug 2, 2013

Hey man,
For what it's worth I have built a cohnis/gm (poor cousin of 9 continent) based rig that is owned by a 75 year old dude who admittedly pedals a lot and also is pretty light, and who has good throttle control and likes to cruise around 35kph (not too much shy of your lower part of the range..)

I used a Grin Cycles 25amp CA plug in Controller, and built a custom Lipo battery pack of 12s 24 ah (split pack made up of two 3*6s 8ah in series) which I managed to make fit into a high end camera bag with telephoto lense extension.

Full configuration was 26" cohnis/gm (unsure of turns but has a 1:1 ratio of volts to km/h... just by chance

)

25 amp surge GrinCycle's controller

Lipo nominl 48v 24 ah custom battery

he rang me after his first 90km ride, to tell me he still had above 3.6v/cell.

As said, he is light and pedals a lot and I am unsure of his average speed, I suspect around 30kph

Here's a pic of what the rig looks like (In for its first service)

**Edit Note Controller has regen, I think the dude gets about 10%, but unsure

Joe

muffinman · Aug 2, 2013

thanks for that input winkinatcha! lol gives me hope. id be willing to sacrifice speed for distance.
i asked this hypothettically to get an idea of the extreme high end of how much battery i would need. i do 20km rides with relative ease, and entirely unassisted. i could probably do 30-40, if i paced myself better. my biggest problem is battery though. i dont think i could build one, that id be comfortable with on that kind of haul. ill have to buy one, and somehow make it fit.

Joseph C. · Aug 2, 2013

muffinman said:
thanks for that input winkinatcha! lol gives me hope. id be willing to sacrifice speed for distance.
i asked this hypothettically to get an idea of the extreme high end of how much battery i would need. i do 20km rides with relative ease, and entirely unassisted. i could probably do 30-40, if i paced myself better. my biggest problem is battery though. i dont think i could build one, that id be comfortable with on that kind of haul. ill have to buy one, and somehow make it fit.

Hmmm...may be we need more specifics. :mrgreen:

What do you want to travel those distances for? Is it for work or just for the pleasure? Will you need to carry stuff with you? Does it matter if you are heavily exercising?

I've travelled a total of about 90kph in one day on 1.6 KW/hr of battery over several trips without the need to recharge. It took just over three hours travelling at about 30 kph. Now an ordinary road bike could easily do that but I wouldn't have been able to haul loads of up 65 kg on a racer. Nor would I have had protection from the rain.

muffinman · Aug 2, 2013

ok, the real senario: my girlfriend lives about 90km away during the summer. i dont have a car, and there is only a bus that goes there and back 3 days a week. makes it hard to see each other. i cant afford a car, and a motorcycle will cost a fortune in insurance. thus, an ebike seems like a possible lower cost option. i understand its not the BEST option, but hey, im trying to think outside the box lol. the ebike would also be used for commuting to school during the summer, as the summer bus schedule sucks. that is merely a 12km ride, and id only NEED assistance one way. anyhow, this thread was just to hash out feasibility of my idea. i get a lot of ideas, but sadly, most are doomed by reason.

muffinman · Aug 2, 2013

my plan for luggage was to bungie/ratchet strap my duffle bag to my rear rack. nothing fancy. maybe use panniers for the extra battery, with my daily battery in the triangle.

hypothetical range question..

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