Ebike 12 miles range and a speed of 25mph kit, Help plz!

[Zersixs]

Hi! I currently take the bus to school and it takes an average time of 50min (same with school to home) and i wondered if i could buy an ebike kit
with the use of 800$ ? I want an continuous speed of 25mph and atleast a range of 12 miles, i only weight 128 pounds and i could assist pedaling
for atleast 5 miles. Is this possible?

I thought of something like this...
(I already got a bike i could use)

http://goo.gl/EtRLh6 (Link to an Ebay kit, cost is $240 including shipping)

http://goo.gl/2O8OFL (Link to an Ebay Battery pack, cost is $300 including shipping)

Would that do the trick or am i way off? Please help, thank you!

 

[Ykick]

You've left us an incomplete picture, my friend.

In order to advise sources you need to at least provide your country of currency and shipping/receiving. It would also help with determining what, if any, laws you may need to be aware of for your local jurisdiction. This isn't NSA, we don't care what street you live on but continent, country, city can help us help you….

Next, is this 12 miles round trip or one way? Would you be able to charge at the mid-point of your commute? While not ideal, it's a way to work with a smallish battery.

Your battery link/eBay is very small capacity and remember with batteries - they never gain more capacity as they age. It's all downhill from the beginning dozen "complete" charge cycles. Also, small capacity bears more stress under use so that will prematurely age/damage it as well.

If you were to double the battery capacity to 20Ah, I'd say "easy" but that's a large package to mount someplace on a bicycle. Maybe a 48V/15Ah battery is a good compromise? Can't really advise anything further until you fully complete the questionnaire.

Welcome to the forum and good luck with your journey of the EV revolution!

 

[wesnewell]

Welcome to ES****Do this before your first post or now (it's retroactive)*****
Please go to the User Control Panel, select Profile, and then enter your city, state/province, and country into the Location field (country minimum) and save it. This will help people help you. Example: Wylie, TX, USA. or just USA, but country as a minimum. Without knowing what country you are in it's hard to make any recommendations. Thank you.

What you want is easily done for $800, but to make the right choices, more info is needed. Size and brake type of your bike? With shipping, both of your choices look expensive to me, Depending on what country you are in, there are probably better choices. That battery pack is 2C max, so really just a 1C constant, which would limit the controller to 10A, and that's not enough. And it's too small for the range you want at 25mph.

 

[Zersixs]

Hi, i feel ashamed i diden't answer those questions and im very sorry. I live a bit outside a city named Halmstad in (Oskarström)
It is 12 miles one way where i then can stop and charge my battery in school for about 6 hours. In Sweden the maximum speed ur allowed is 20mph and it must have pedal assist.

Here is a picture of the bicycle, i also measured some important parts



What do you think?

 

[Ykick]

Don't feel ashamed, it's called learning and you pickup quickly.

Your frame has a nice big triangle so I'd recommend a 48V/15Ah battery in a frame bag. Such battery should accomodate a nice variety of controller/motor options and the fact you can recharge 6 hours during school should keep it happy for a very long time. I would suggest 2qty chargers once you settle on a battery so that you have a spare and won't destroy your only charger hauling it around everywhere.

Front motor is okay but it's more stealth and natural feeling IMO to go rear hub motor.

The next choices would be geared hub motor or direct drive (DD) motor? Kinda depends if you wish to keep weight to minimun (will you carry up stairs, etc.) and/or your terrain, if it's hilly?

I'll bow out for now and allow others to share much better wisdom but it seems that you have a very doable plan and realsitic expectations of what you'll be getting into.

Good luck and enjoy the ride!

 

[wesnewell]

48V 500-1000W rear DD kit would be my choice. There are several on the Swedish ebay. A 48V 500W in 26" wheel will typically do ~25mph, while a 48V 1000W will do ~30mph. A 15ah 48V lithium battery should be plenty at 20mph. Put Sweden in your first post title page and maybe others from there will notice and jump in with local advice.

 

[Zersixs]

There is not very many hills on the way maybe four to five hills in total like the one shown below and they take up a maximum of 2.5 miles out of 12 miles (one way )
and what size is my wheel ? i have no clue if its 20,26 etc..

 

[wesnewell]

If the measurements in the photo are correct, it almost has to be 26" tires. 26" rims are ~22" across. Size should be on the tires to be sure. ETRTO for standard 26" rim is 559mm.

 

[Zersixs]

the diameter across the whole wheel including tires is 64cm.

 

[dogman dan]

The motor appears to be a medium powerful direct drive one. I'm not real familiar with that particular one, so the top speed of it is not known. Depending on the winding, it could be between 20 mph and 30 mph when run on 48v.

But it will do the job, at whatever speed you get.

The battery is a brand with a history of not performing to specifications. That does not mean every V power battery doesn't work, just that the vendor has a long history of using cells that may or may not perform to spec. Don't misunderstand, many bikes are running great on V power batteries. But this vendor has sold quite a few that had problems. I think many of the problems were directly related to damage in the shipping, and his current battery is not as vulnerable to that shipping damage as the old ones were.

It's just one of those deals, where you pay your money and most likely you end up ok, but V power is not on my list of brands to trust. In the past, the V power batteries had a tendency to have real world capacity less than it was supposed to.

So since the size you chose is very small for running a larger motor like you picked, it becomes a MAJOR problem if your get one with only 8 ah of usable capacity. I'd say go for the 15 ah size. In 10 ah size, each cell has to work too hard to provide the amps the motor will draw. In 15 ah size, the strain on each cell is much less, and if the real world capacity is only 12 ah, you will still be ok.

A 48v 15 ah battery will have the power to do your 12 miles with no pedaling at all. If the speed is less important to you, a 36v 15 ah should be priced similar to the 48v 10 ah. A 36v 15 ah would be large enough for the motor, and still make the 12 miles easy.

 

[Zersixs]

Thanks for your information and advice dogman!

I want the speed to be atleast 20mph and i think that all the advice i got on this topic is enough!
i gonna go for a 48V 15AH battery pack with a rear 48V 350 or 500 watt motor.

 

[wesnewell]

the diameter across the whole wheel including tires is 64cm.

Certainly a 26" wheel then, and even if it's some off the wall size, a 26" wheel will fit.

 

[dogman dan]

With 48v, you'd have 20 mph with even the very slowest of motors. More likely you will have 25-30 mph top speed. Riding 20 mph most of the time will be much easier on the battery, extending range a lot compared to riding full throttle.

 

[heavymetalthunder]

A couple of things to remember is to install head and tail lights. To many other drivers you are a bike not a e-bike. Later on you might consider getting some good road tires and good inner tubes, nothing like getting a flat tire on the road.

 

[jay7264]

well my bike is only 250 watt geared hub motor and my battery is 13ah 7s and I make my 10 mile commute one way at 16 mph

 

[d8veh]

Your budget is just enough to get Bafang BPM kit from BMS battery which will meet all your requirements. The motors are well tried and tested with a good reputation for reliability. Their batteries are good too. If you can afford it, the 500w CST motor is really nice. Max speed at 36v is 24mph. The 328 rpm BPM is a bit faster at about 25mph, but, like with the MAC, you can only fit free-wheel gears instead of nice cassette gears that can go on the CST motor. There's options for better controllers with LCD displays, which are more suitable for using pedal sensors.

Basic BPM kit:
http://www.bmsbattery.com/ebike-kits/347-bafang-350watts500watts-bpm-motor-e-bike-kit.html

This is a good battery to go with it:
http://www.bmsbattery.com/36v/445-36v-15ah-lithium-ion-electric-bicycle-battery-pack.html

Total cost including shipping is $670, but you need to add torque arms. The deluxe CST kit with sine-wave controller and LCD comes to about £850 including shipping.

If you go this route, post your shopping list before ordering it, so that it can be checked.

 

[Racer_X]

I would like to add that $800 US dollar is a bit over 5,000kr Swedish kronor. Unfortunate for us in Sweden just the import tax alone (tullskatt) will be 700 - 800kr OR 130.00 dollars in import tax, and there is NO way to get around that one. So you need to make room for that into your budget.
One question are you planing on riding year round? Direct drive motors are better for those conditions.
If you are planning on riding year round consider some spike tires (dubbdäck) another 600 to 900kr. Otherwise it is going to be a dangerous proposition ice + 40/kmh.
looking forward to hearing which way your going to go on this.

 

[Zersixs]

No, i will not ride the bike in snow only in summer weather and i did actually not think about the tax.

D8veh, i gonna check that kit out, thanks.

 

[Ch00paKabrA]

I dont see why you would need a 20ah battery to go 12 miles. My bike only goes around 20 mph, not 25, but I am getting around 2 miles per amp hour and I run two 3ah batteries in parrallel regularly. As far as the cost is concerned, I am into my current bike for $600 and I have a 13 to 14 mile range and that included $250 for the bike.

I went ass backwards on my first build and wasted a lot of money but this time around, I think I nailed it. 20ah batteries are bulky and unappealing. I have 2 6ah batteries. one is in a bag under the seat and the other is in my backpack. This works very well. also by having 2 smaller batteries, if one melts down, I am not immobile because I still have another.

here is mine: http://endless-sphere.com/forums/viewtopic.php?f=3&t=54228

Good luck with your build

 

[Zersixs]

That's a nice looking ebike you got there Ch00pa, i actually found a new path to take when traveling to and back from school. It is 2km longer (21km total) but it is almost completely flat the whole way,
and more safe because it's way less cars than on the main road =)

Thanks.

 

[dogman dan]

Yeah, you don't need 20 ah, unless you get a 24v system.

At 20 mph max, 2 ah per mile sounds about right for 48v. A bit less miles per ah at 36v. This is because a 36v 1 ah battery has about 36 watthours, while a 48v 1 ah battery has about 48 watthours.

When you talk ah per mile, you must state the voltage. I have recommended 1 ah per mile to pick a size for 36v batteries for years. You get better than that nearly every day, but worse some days. So for a 12 mile ride, 15 ah of 36v is plenty, or 10 ah of 48v that can handle more than 2c discharge.

15 ah of 36v is also good for the days you have a detour to do something on the way home. Or you want to take a safer long way home.

However, 20 ah of 36v is ok enough to carry. 20 ah of 48v is not. It's not in your budget anyway, so no need to say much more about that.

 

[Zersixs]

but dogman, can i have a continious speed of 25mph using a 36v motor? since i take this new path i can hold a higher speed. Please reply, thanks!

 

[dogman dan]

Yes with some motors. the most typical ones might only go about 23 mph on 36v. Much depends on the exact motor you choose.

You might need to be willing to compromise a bit on the speed. For a 12 mile ride, 20 mph can be plenty fast. It won't take that long to ride 6 miles or even 12 miles one way at 20 mph.

Ideal would be a 48v 15 ah, but that starts bumping up costs. Ideal for the speed, and longer range when going that fast. 48v 10 ah will do it, but for the larger faster motors, you'd have to choose a battery with a decent discharge rate to run that hard on only 10 ah size. Something claimed to be 4 or 5 c rate, rather than the typical less expensive 2-3 c rate stuff.

Choosing to ride slower can mean needing a LOT less expensive battery.

 

[Zersixs]

Yeah, but if i also pedal, can i achive a higher speed?
Like 22mph or so? Or am i stuck at what the motor can handle

 

[wesnewell]

With 44t front and 14t rear sprockets it's hard for me to keep up with the motor above 16-18 mph. Don't count on adding any speed unless you've got a high gear inch ratio, It would take a 90rpm cadence to keep up going at 21.9mph with my gearing. You'd need a really fast wind motor to go above 20mph at 36V. How fast would you need to pedal? Find out here.
http://sheldonbrown.com/gears/