Dischargecurrent needet from 1500w motor?

[Uttermayn]

Hey there
I have been searching my fingers thin for the right ebike kit for me. I dont really need it to commute, even though i would like to say so. But nothing wrong with having af little fun on the way to work.

I will be riding under 10 miles and really just want the bike to be kind of stealthy but with an ok amount of power.
I have almost decidet on this ebay kit. 1500 watt which i figure will provide me with the right amount of power.

Link to motor
http://www.ebay.co.uk/itm/1500W-70KM-Per-Hour-Hi-Speed-Electric-Bicycle-E-Bike-Hub-Motor-Conversion-Kit-/221759028735?pt=LH_DefaultDomain_2&hash=item33a1de3dff

The question that comes to my mind is. How much power will i need to get the maximun 1500 watts out of the motor, and still be able to carry the battery just a tad stealthy.
I understand the hole amphour thing, and if i multiply 48 volta with 11 ah in this seatpost battery im linkin to further down, the result is 48 x 11 = 528 sp i figure that at max power that would give me 500 watt for an hour so approxemately 1500 watt for 20 minutes. Which to me is a great start to have some fun.

I allmost pushed the buy button when i read something called discharge rate... I can not find annything on the battery and not either on the motor.
So my question is. How much dischargecurrent will a 1500 watt motor need from the battery? How "small" can i go?
I have tried searching for it but found nothing.
Sencirely hope you can help me solve this..
Some further explanation would allao be very nice..
Have a great night
Cheers from Denmark

Link to battery pack
http://www.ebay.co.uk/itm/48V-11AH-Seat-Post-Mount-Lithium-Ion-Battery-for-Electric-Bike-Conversion-kit/391129383186?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D30106%26meid%3Dd83da8640cf240b3be07dc0269aa939e%26pid%3D100033%26rk%3D2%26rkt%3D4%26sd%3D221759028735

 

[arkmundi]

... this ebay kit. 1500 watt which i figure will provide me with the right amount of power.
Link to motor
http://www.ebay.co.uk/itm/1500W-70KM-Per-Hour-Hi-Speed-Electric-Bicycle-E-Bike-Hub-Motor-Conversion-Kit-/221759028735?pt=LH_DefaultDomain_2&hash=item33a1de3dff

Which does not list the amperage, a constraint of the controller, needed to determine power P = I * V, hence battery size. Never buy eBike components without knowing what you're getting. For about the same money, you can get a MAC 8T from http://em3ev.com/store/, with a controller that will deliver 40 amps and take a 48 volt battery, so run a full 2000 watts. My ride, so know...

 

[Uttermayn]

Thanks for reply. Can you perhaps link me to complete setup like yours? Isnt the mac hub a geared hub? Will i be getting the same top speed?
Thanks so much..

 

[arkmundi]

Go to the http://em3ev.com/store/ website and browse the kits, with or without battery. I have the MAC upgraded motor kit. There are lots of options which I have listed in this link: http://endless-sphere.com/forums/viewtopic.php?f=2&t=63524&p=951894#p951894

 

[Uttermayn]

Ok i am lookin further for kits with all the info i need, i came across a kit with 1500 watts power but in wattage it say >400 what does wattage mean in this context? If the motor is 1500 watts then what does wattage mean?

 

[arkmundi]

A motor's wattage is a maximum, how much combined voltage and amperage the motor can handle without doing damage. Actual wattage delivered to that motor is a function of the other components - battery, controller, wiring and connectors. A battery is rated in volts, but also max current or C-rate, and amp-hours, a capacity measure. Controllers are rated in amps - typically 20, 30 or 40 amps, though there are higher amp controllers. Wire is rated in gauge, and the smaller the number, the larger the diameter of the wire, so the more current it can carry safely. Connectors are rated in amps. So for instance, in my setup, I use 12 gauge wire and anderson powerpole 45 amp connectors. My controller is the Infineon 12-fet 3077, rated at 40 amps. My battery is 20 amp-hour capacity battery, with a C-rate of max 30, meaning it can deliver upwards of 400 to 600 amps. A 48 volt battery. As a system, its simply a 48 volt 40 amp system. So P = I * V or about 2000 watts. The MAC 8T motor is rated for upwards to 1500 watts. So I'm pressing its limit, but its handling the power just fine, so far. The 'upgraded' MAC has heavier gauge phase wires, so more suitable at higher power levels. Hope this helps.

 

[999zip999]

Mac's can run at 1,800 watts
So a 48v battery (54v charged ) x 30amps = 1620 watts, then you need to find a battery to match the controllers demands. It's the controller that is the brains that demands. Your battery will give till dead.
It's labeled 600watt motor. Yes 1,800 watt.

 

[arkmundi]

Mac's can run at 1,800 watts
So a 48v battery (54v charged ) x 30amps = 1620 watts, then you need to find a battery to match the controllers demands. It's the controller that is the brains that demands. Your battery will give till dead.

And the motor will take till dead. Yes, its why in determining a setup's power, I use the controller amps and battery voltage. There are other ways of making that calculation.

 

[999zip999]

Battery to small. Wouldn't last.

 

[dogman dan]

If it wasn't quite clear yet, there are three kinds of wattage specs.

1. The rated wattage of the motor. Many of us run a lot more power than that rating. Many motors can easily take 3x their rated wattage for quite some time. But they will never overheat at the rated power. So a 500w motor can run infinitely at 500w. But at 1500w, it's unlikely you can carry a battery big enough to overheat it before your run out of power.

2 The actual wattage your controller allows. For example, a 48v 40 amps controller will allow 2000w. 48 x 40. However, if your bike goes 30 mph, that typically takes about 1000w of power. So even with a 2000w controller, the motor will not pull much more than 1000w.

3 Outright lies. Or close. see the sentence above. Because max amps, and the amps you use cruising are different, you will see the same 48v 40 amps controller sold on ebay as, 1000w, 1500w, and 2000w. Very confusing. Try to find out the actual amps spec.


On to the battery.

Your battery needs to be able to put out the max amps your controller can. So a 48v 40 amps controller means you need a battery able to put out 40 amps, at least for a burst. Ideally, 40 amps continuous. One reason a lot of people choose a 20 amps controller, is that it will help keep the cost of the battery down, needing only 20 amps.

 

[Uttermayn]

Dogman Dan you singlehandwt answered all my questions i had i one single post.. I now feel that i am able to make som reasonable discisions about what to choose.. I am very thankfull to you and all others trying to help.. Thanks a lot

 

[rider95]

Don't sweat it the mac is the best cheapest most reliable motor for you don't split hairs on cost buy everything plug n play your profile doesn't say were your from so don't know if your state side . If you buy every thing plug n play your biggest problem will be to were to put your battery , please use a bike with disc brakes know the dimensions of the battery you are goanna use and understand were it will fit on your bike . Don't buy more battery then you need battery's are heavy and expense. EMV3 is a good choice he,s in china good prices , Ebike (dogman dan ) has good stuff he,s stateside and he,s already been helpful to you .

 

[Uttermayn]

Thanks.. originally i was looking for at gearless hubmotor hens theaimplicity of it.. I am worries that the mac motor will break down, but ofcourse there is allways the possibility of spare parts.
I am from Denmark so it needs to be shipped to europe.
i was looking on hes website but i am looking for af top speed more like 60-70 kph than 50 kph.
Do you know if that is possible with those kits? I would allso like af battery that fits inside the frame and not to big.

 

[arkmundi]

rider95 » Don't sweat it the mac.... ++that.. can not go wrong with either http://em3ev.com/store/ or http://www.ebikes.ca/. Contact them, tell them what you want and take a 100% kit - everything you need, including battery. They are the experts. One weekend of assembly. Done.

 

[dogman dan]

60-70 kph is fast for a geared motor. It will take a lot of wattage, far more than a Mac can typically handle, and be reliable. The mac is a 500w rated motor, or close to that. 3x that is 1500w.

72v, and 40 amps, 3000 w at least, will be needed for 70 kph.

Look at much larger motors, rated for 3000w or more. Direct drive motors, like the cromotor, or the larger Muxus and Crystalyte.

70 kph, that realllllly ups the ante, on what you will have to spend on a battery and have decent range.

But really, fun as 70 kph is, 50 kph is plenty, and suits the average bikes tires and brakes much better. 50 kph easy with the Mac, and 1500w.

 

[arkmundi]

i was looking on hes website but i am looking for af top speed more like 60-70 kph than 50 kph.
Do you know if that is possible with those kits? I would allso like af battery that fits inside the frame and not to big.

Those are mutually exclusive goals, so you have to decide. 50 kph is possible with a MAC 6T or 8T and a 48V battery and 40 amp controller, just barely. And a 15ah battery pack will fit, just barely. So all those - power, speed, size, weight are inter-related. It works on a bicycle, and has a proven track record of safety & reliability.

As soon as you step into the 3000 watt power range, yes you can approach a 60-70 kph goal, but you compromise all the rest. First off, you should no longer be considering an install on a bicycle frame with bicycle components. You should be thinking moped. The pictures of bike-like electric vehicles in that power range have been constructed more like mopeds, so have better frames, good shocks, heavy-duty rims & spokes, hydraulic disk-brakes, etc. You can do that, but expect to pay for it. And no longer "stealth", a more obvious motor-cycle like vehicle, requiring all the other things to get that street legal, registered, etc. So lights, turn signals, brake lights, registration and on and on.

You have to prioritize your goals and understand which goals are incompatible, like I want a 1500 watt bicycle that goes 60-70 kph and is stealthy, with a light weight battery pack that fits in the frame. Those goals are achievable, minus the 60-70 kph part. Stick with that and be happy you're getting great advise.

 

[Uttermayn]

@Arkmundi - I understand your reply, but i allso said that range was not so important. I have seen several bikes with lots of power but short range and "small batterypacks, so i do not believe your claim to be completely true. ". I wrote that im building this bike to have fun, not to commute several miles. Furthermore you can't blame a guy for askin, by the tone of your post it seems like you think that i am expecting advice and not beeing thankful?
Did you somehow get the idea that i do not apreciate the answers given to me? As i have written several times, i am very happy and thankful for the help given to me.
/Anders