Help 24 volt eBike users!!!

[larry3t@yahoo.com]

I am starting to build an eBike from my beach cruiser.

Got my motor yesterday:
A

from a bike shop in Utah via eBay

It has only 3 wires coming out and is a sensorless brushless front

I also have a Chinese controller from eBay coming thats in NYC already.
It is a 250 Watt 24 volt 10A controller without hall

I am poor and would like to test it and initially use it with a lipo battery like the RC guys use.

How many amps would I need? (ex: 5000 mAh?)
How many volts - none are exactly 24 volts.

Is 6S 22.2 Volt too little?
Is 8s 29.6 volts too much?

Is it possible to get some other combination/arrangement.

Please any one who has done it or heard of it done. Many thanks!!!
Larry

 

[LI-ghtcycle]

8S should be enough for a 24V system, really depends on what your controller is designed for, however, I would guess that would be perfect.

On the capacity, it really matters how your going to use it, where and what distance you travel.

I would say a good rule of thumb is no less than 10AH, and plan on only using 8AH's of that 10.

Are you building the wheel yourself too? Sounds like a great project!

 

[wesnewell]

6s lipo would be the safest. I imagine LVC on your controller is about 21-22V, and that would be about perfect cutoff for a 6s pack, shutting off at or just under nominal voltage. And that's only a 180W rated motor. A 10A 24V controller will put ~240W into the motor using 6s lipo. I'm pretty sure 8s would also work, but if you ran it until LVC cut off power that would considerable over discharge an 8s pack, or even a 7s pack. This looks like a really weak setup. I hope you plan on doing a lot of pedaling with it and don't plan on going more than about 13mph on battery alone.

 

[dogman dan]

7s would be ideal, but likely you can't find it. You could take a 3 s pack and series connect it to a 4s pack. I'd say run 6s, unless you need more speed. 25v when fully charged. If that is the case that you need speed, you blew it buying a 24v controller. If you really need speed, then get a 36v controller and run 10s lipo.

One single 6s 5 ah lipo will have about 70-80 usable wh in it. So it won't take you very far. But a 24v bike is pretty slow, so pedaling and going that slow, you should be seeing about 20-25 wh per mile. So about 3-4 miles max. Likely you will want 2-4 of those 6s packs to go any real distance.

 

[Ykick]

Hot off the charger 6S will be around 25V. By the time it gets a little below 22V the pack will be close to empty and you risk damaging a cell. Wesenell makes good point about the controller LVC working best on 6S too.

OMT - more plentiful 6S bricks/chargers than 8S. But you should definitely go at least 10-20Ah. 2-4P (parallel) arrangement.

 

[ZOMGVTEK]

6S should work fine on a '24V' bike. The two 24V controllers I used, had an LVC set to 20.5V, which is 3.41V per cell. This should be OK for most 24V bikes, since you would tend to have ample cells in parallel to keep imbalance in check.

You can use almost any battery capacity. 5AH is about as low as you would want to go, and that would get you maybe 5 miles. Assume every 6S 5AH pack will take you 5 miles with light pedaling, use that to determine how many you want.

I put 2-3 miles on this setup. Not much power, but it had enough speed to be acceptable.The final build used 10 6S 5AH 20C Turnigy packs.

 

[larry3t@yahoo.com]

Wow! Thanks for the help guys!!! Great info. Thanks for the encouragement! Will keep you posted with pics. From the north end of lovely Cayuga Lake left by the last glacier.
PS Chinese controller just arrived as well as throttle from another seller that will not fit without being operated on (4 pin throttle, 3 pin on controller).
Throttle has a spring like you have to hold it down all the time - are they all like that?

You can see from the pic there are 4 color wires for the throttle: red white black purple
Unfortunately the controller has 3 throttle wires for the throttle: red green black

Great looking bike btw, I'll be ashamed to show you mine!

 

[dogman dan]

Spring on the throttle, just like a car has, or a motorcycle. You want it to snap back to zero.

The wiring should be fairly simple, but may still require guesswork. The 4th wire on the throttle is for the battery guage on it. You don't need it, and most don't want it. Very often this is a purple wire, with the other three black red and white. So b to b, w to w, r to r, should work. You likely will need to put new connectors, but you may be able to just remove the contacts from the housings, plug them in, then tape em up good or use heat shrink to insulate them.

 

[DAND214]

I also have a Chinese controller from eBay coming thats in NYC already.
It is a 250 Watt 24 volt 10A controller without hall

Are you sure on the sensorless controller? Pic says with halls

Some are both, but this ones states WITH.

Dan

 

[larry3t@yahoo.com]

Yes, this is the link http://www.ebay.com/itm/16066337888...X:IT&_trksid=p3984.m1497.l2649#ht_2473wt_1141

Check the red writing half way down the ad.

This other crazy guy tested it (he's sharp - way above my pay grade) here: http://www.etotheipiplusone.net/?p=1688

BTW I ordered a 6s 5000mAh Turnigy lipo at HobbyKing for $50 (+$10 shiipping priority mail) to test it.

 

[larry3t@yahoo.com]

Thanks so much guys! Sounds like 6s 7s or 8s would be the way to go, with 6s getting the majority opinion. I'll let you know how it goes when I'm wired!

 

[kmxtornado]

Not trying to discourage you or anything, but I wish you talked to us about your project before you bought your stuff .There aren't a lot of 24v bikes here on the forum from what I've seen so far. Lots of expertise, but that voltage is really low for a full sized upright bicycle. Have you had a chance to test ride a 24v ebike before?

 

[larry3t@yahoo.com]

Interesting question.I got an idea in my head I'd like to have one when I was on the Pedelec Forum and didn't know about ES. I love all the stuff you put up researching your project with many possibilities. I originally was going to buy a CB450 mongoose electric bike that was 24volt used for $150. Watched a video on you-tube. It was kind of loud and I prefer not to draw attention to myself, so I'm going the old Tongxin route. Wish I had 36 volt, but I only paid $69 for this one, $87 with shipping from Utah. Find the seller on eBay helpful. Thanks for your help.

 

[dogman dan]

A 36v controller would not cost a whole lot, and you may even be able to use the one you have at 36v. If you have some 6s packs, adding some 4s packs gets you to 36v with 10 s.

So you aren't stuck with slow 24v if you don't find it enough. You can easily upgrade some later.

 

[wineboyrider]

A 36v controller would not cost a whole lot, and you may even be able to use the one you have at 36v. If you have some 6s packs, adding some 4s packs gets you to 36v with 10 s.

So you aren't stuck with slow 24v if you don't find it enough. You can easily upgrade some later.

What Dogman said. I had a controller for my minimotor from Ebikekit and it looks just like the one you have, but rated for 36v. It was a sensorless controller.
8) 8)

 

[kmxtornado]

Larry, you can also follow my thread on my mini scooter (from my sig). I'm putting 36v onto the little foldable scooter that's currently 24v stock. Someone also pointed me in the direction of http://forum.modifiedelectricscooters.com/viewtopic.php?f=10&t=866 which has been super helpful. For people like us with smaller bikes/scooters, it's a good forum. Activity there is less, but there's at least one guy over there that's been of great help and responds superquick.

That forum is also helpful for people with modest budgets like myself. I didn't want to put too much money into the little bike being that I already have a few projects going on. The typical scooter owner (if I dare say) has a lower powered ride and may be younger with less funds to play around with. So it makes sense that mods found there are on a smaller scale. Of course there's monster modders there too with Razor scooters that go 40mph, but that's not typical.

From my experience chatting around there, those that are older on that forum tend to be fathers tweaking their kid's rides. They're not up for spending $1,000 on a kit. That's a big contrast from the power horses here. Nothing wrong with a 1,500w system and I've received tons of quality help here and I'll always respect the contributors here. Just want to mention there's other communities out there that may be useful for you in a different way. Check it out. Highly recommended.

Again, not to steer you away from here. This is an awesome forum as well. It's just good to give your project some exposure across different boards so you can get the most feedback and make whatever decision that's best for you. Good luck and please continue to let us know how it goes. We're all interested to hear - at least I am.

 

[larry3t@yahoo.com]

I looked at the controllers and didn't see any for sensorless motors like my Tongxin. I'm glad to have a low power controller as Tongxins are not known for handling alot of power well and mine being a 24v one even more so. Thanks though!

 

[larry3t@yahoo.com]

Dogman, you can run 6s and 4s in serial? Thought maybe they had to be the same number of cells. I have a turnigy 6s 5000mah now.

 

[dogman dan]

You have to have the same voltage to paralell cells. So you'd paralell your 6s packs, paralell your 4s packs, then put the 6 s and 4 s bundles in series to make a 10s total.

Series connection does not have to be all the same cell number, but when you go to charge it, you couldn't paralell the 6s with the 4s to charge. You'd have to use a 10s charger, or charge the 4s and the 6s seperately.

Most people though, if they wanted more speed, would just buy more 6s, and then series connect them to have a 12s, 44v pack.

 

[REdiculous]

Not trying to discourage you or anything, but I wish you talked to us about your project before you bought your stuff .There aren't a lot of 24v bikes here on the forum from what I've seen so far. Lots of expertise, but that voltage is really low for a full sized upright bicycle. Have you had a chance to test ride a 24v ebike before?

My 12v bike is faster and better than my 24v bike, and they use the same battery pack...12v 38ah or 24v 19ah SLA, depending on which bike it's on. :lol: :wink:

 

[sangesf]

Not trying to discourage you or anything, but I wish you talked to us about your project before you bought your stuff .There aren't a lot of 24v bikes here on the forum from what I've seen so far. Lots of expertise, but that voltage is really low for a full sized upright bicycle. Have you had a chance to test ride a 24v ebike before?

My 12v bike is faster and better than my 24v bike, and they use the same battery pack...12v 38ah or 24v 19ah SLA, depending on which bike it's on. :lol: :wink:

Depends what amps you're pulling...

If your pulling 30a from the 12v and 10a from the 24v, sure it'll be better, but prolly won't get you as far.

 

[REdiculous]

Depends what amps you're pulling...

If your pulling 30a from the 12v and 10a from the 24v, sure it'll be better, but prolly won't get you as far.

My point was that battery voltage is only one part. If you're not trying to be fair about it, it's actually pretty easy to have a 12v bike beating a 24v bike.

I just got and cleaned up this 24v bike, I've had it maybe a week, but my initial testing...yeah, this 250w thing is pathetic. On the third run up a very-light hill, it stalled just before reaching the top. My 12v bike can do that hill no problem - it doesn't slow down as much and it certainly doesn't stall on the 3rd run for no apparent reason.

With the 24v bike stalling on the hill, you'd think it was the current-limit, but it made it the first 2 runs...barely. That leads me to believe the 24v bike will have worse range, except maybe the LVC is low enough that I can pull more from the batteries on the 24v bike than I can on the 12v bike. The 12v bike is LVC-limited only, since everything but the reduction I made is ready for 1kw or more and I'd be lucky to get 500w from the saggy SLAs.

The biggest difference is the speed, actual and potential. My 12v bike is geared for like 50mph (no-load max). The 24v bike is geared for a whopping 15mph, and if you weigh anything, expect about 12mph. I tested my 12v bike up to 21mph, at which point I chickened out and claimed it "illegally fast". :lol: :wink:

Acceleration is fine for both - since they're not that fast, it's hard to tell which is really better without measuring it. That means the 12v bike is better though, because just by changing the gearing, I could double the torque and it'd still have a higher top speed than the 24v bike.

So, um....yeah, you're right.

 

[larry3t@yahoo.com]

As the starter of this thread I am a newbie building my first bike on the cheap and looking for stealth as I have no faith in Mr. Dilan and the NYS senate. As devils advocate if 12v is faster than 24v, shouldn't 24v be faster than 48v? I'm a neophyte but not uneducated and I gotta think that we're comparing apples and oranges somewhere here, as certainly by Teslas time the laws governing all this were immutably worked out. Certainly we don't truly understand what electricity really is, but the laws under which it behaves have made us able to get consistent reults using these laws for the last century.

 

[REdiculous]

As the starter of this thread I am a newbie building my first bike on the cheap and looking for stealth as I have no faith in Mr. Dilan and the NYS senate. As devils advocate if 12v is faster than 24v, shouldn't 24v be faster than 48v? I'm a neophyte but not uneducated and I gotta think that we're comparing apples and oranges somewhere here, as certainly by Teslas time the laws governing all this were immutably worked out. Certainly we don't truly understand what electricity really is, but the laws under which it behaves have made us able to get consistent reults using these laws for the last century.

The battery voltage is just one variable, so a 24v bike can beat a 48v bike, even if it's normally the other way around. It's pretty rare for a 12v bike to beat anything (or work), but it's not impossible for a 12v bike to beat a 48v bike - if the 12v bike can do 1kw and the 48v bike is limited to 500w, the 12v bike should win.

Current-limit, Low Voltage Cutoff, gear ratio(s), etc....everything plays its part to make the whole.

 

[amberwolf]

Also depends on the motor and controller type/etc., such as if it is a middrive or a hubmotor, and what winding the motor uses, gearing, weight, etc. Which batteries are used would make a huge difference, too, since at lower voltages you'd need to be able to sustain higher currents with little voltage drop, so high-C-rate batteries would help beat lower-rate ones.