How to do 60 KPH with no peddle (flat) with only 36V battery

[dogman dan]

Agree with Chalo. Whatever the smallest capacity battery in a series string has is the capacity of the whole string. Have to charge different chemistries sepreately in most cases. So a mixed pack should be charged by the right charger for that chemistry. So a charger for each side of the pack.

More of a why bother thing than a can't be done thing. If you are using lead or nicad, dump em asap.

 

[wesnewell]

Dogman, Every time I see your sigline, I envision some idiot seeing it and taking it too mean what it says thinking he should charge his lipo to 4.3V and discharge it to 2.7V. I sure wish you'd change the way it's worded. How's this: Lipo rules: Cell damage will occur if charged past 4.2V and may occur if discharged lower than 3.5V resting voltage. Normal charge=4.1-4.2V, Normal discharge=3.65V no load.

 

[kmxtornado]

And I thought my thread on going 30mph was a lot to ask for:
http://endless-sphere.com/forums/viewtopic.php?f=3&t=34477

 

[Chalo]

If you are using lead or nicad, dump em asap.

What's the beef with nicad? Too many cells in a pack won't stay balanced? I have often wished for an e-bike that worked as well as my old Dewalt cordless drill, with no special maintenance or care, year in and year out.

I have to admit I have never seen a technically successful nicad powered e-bike, other than a custom made Heinzmann powered bike I helped build in '00, that had solar charging and a Sanyo D-cell pack inside the frame. I don't know how well that one did in the long term.

Chalo

 

[Toorbough ULL-Zeveigh]

What's the beef with nicad? Too many cells in a pack won't stay balanced?

13,760 NiCd cells in the worlds biggest battery.

I have to admit I have never
seen a technically successful nicad powered e-bike,

just had to throw in that qualifier, diddincha?
220(?) sub-c NiCd.
talk to johnrobholmes for more exact info.
wonder what the ole toxic avenger can do @36V.

 

[neptronix]

Dogman, Every time I see your sigline, I envision some idiot seeing it and taking it too mean what it says thinking he should charge his lipo to 4.3V and discharge it to 2.7V. I sure wish you'd change the way it's worded. How's this: Lipo rules: Cell damage will occur if charged past 4.2V and may occur if discharged lower than 3.5V resting voltage. Normal charge=4.1-4.2V, Normal discharge=3.65V no load.

This is totally offtopic, but i agree.

 

[neptronix]

nicad: low energy density, and possibly one of the most toxic battery chemistries ever, having 8-16% cadmum, which is a highly toxic heavy metal, producing fatal effects or permanent kidney damage in very small quantities.

Don't want that shit in the landfills leaching into the water. That's bad news.

 

[dogman dan]

The main disadvantage of nicad, is having to string the cells series first, then charge each string one by one for a large pack. Then there is the disposal issue.

I wanted the sig simple and easy to understand. Don't do these things. Now I added the generaly accepted do, and point em to the FAQ's.

 

[veloman]

This was my first ebike. It went about 30mph if I got down low. It's no load speed was 46mph. I had a small 30amp controller on it. Battery was 24v SLA.


What does that tell you?

If you gave it enough amps, it would have gone 37mph. Though it wouldn't get there fast and not likely last long before overheating. The gear ratio was not good.


My point is that a non-hub drive ebike can certainly go 60kph if the motor is strong enough and you give it enough amps at 36v.

My current ebike uses a 6 turn Mac hub at 36v and will go 32mph. That's your best bet for a hub motor. 32 is not 37, but it's a heck of a lot more reasonable.

 

[dogman dan]

Nobody is saying it can't be done, just that hubmotors aren't generally designed to go that fast on that voltage. Wasn't this a hubmotor goes 60kph on 36v thread? Then we all said hubmotors usually won't go that fast unless you volt up?

I'm sure there are plenty of examples of 36v, a decent non hub motor, and the right gearing going very fast. I'ts just that if you insist on a hubmotor, they tend to need overvolting to go fast. A fast enough winding to hit 60kph on 36v would perform pretty poorly on steep hills. So few want one.

But there does happen to be a 5302 for sale right now. In the new section I think. If any motor would do it, that one would. Not sure what controller you could get to last though.

 

[kmxtornado]

So what's the consensus on max speed on a 36v battery powering a hub motor? 25mph (or 40kph for you non us folks)?

 

[veloman]

32mph easy on 6 turn Mac in 26" wheel with 36v battery capable of 25+ amps constant or 30amps if you sit upright like most ebikers

 

[Philistine]

I think my BMC V3 on 36V in a 26" wheel (me being 95kg), no pedalling, on a flat, I could get it to about 45-48kph, and a touch over that with my X5303.

 

[cell_man]

A 6T Mac does about 46kph on 12S A123 from what I remember (26" wheel). You also have the option to set speed 3 on the controller to 120% on the controller. That might get you close to 60kph. Maybe not quite 60kph, but shouldn't be too far off it. 120% makes an 8T go 6T speed on 48V, about 60kmh, it does about 50kmh on normal 100% speed setting.

 

[dogman dan]

There you have it from the source. You could wind your own motor for even faster on 36v, but you'd simply find that it was sluggish and slow the first 20 feet from a stop, and would bog on hills that weren't so steep and make lots of heat. So nobody is selling such an impractical motor for general use.

But if your use is to run 10 or more miles with no stops on the flat, such a custom motor would work fine. Pedal to speed and let er rip. But silly me, I'd just add more voltage if I wanted 60kph. Stock 9c motor and 72v does the trick quite simple.

Or a faster motor such as a 2806 or 6t mac and 48v gets you pretty close, at 50kph.

 

[cell_man]

I read back my previous post, not very clear...

Here is a quote from Veloman, which backs up what I said, although I would say that is probably quite ideal conditions to get that high a speed on that voltage:

32mph easy on 6 turn Mac in 26" wheel with 36v battery capable of 25+ amps constant or 30amps if you sit upright like most ebikers

The BMC V3 and Mac 6T have about the same no load speed.

I generally see close to 20% increase in max speed when going from the standard 100% speed setting to the 120% speed setting in the infineon type programmable controllers with the Mac motors, assuming the motor is limited by rpm rather than lack of power of course. That's not too far off of the 60kph on 36V requirement. This setup is not gonna be in the least bit sluggish from zero either.

 

[veloman]

Here is a quote from Veloman, which backs up what I said, although I would say that is probably quite ideal conditions to get that high a speed on that voltage:

32mph easy on 6 turn Mac in 26" wheel with 36v battery capable of 25+ amps constant or 30amps if you sit upright like most ebikers

.

More accurately, my scenario:
26x1.5" tire (a tad smaller than typical 2" wide tire, slight decrease in speed / more torque)
38v actual under load
21amps
32mph - yes, that's definitely in ideal conditions, 175lb rider, tight clothes, aero tuck. Don't expect to get to this speed on such low amps like I'm riding, at least without putting in some good pedaling and fitting my profile above. Realistically 30mph, not 32. I think when you get near the high end of the motor's speed, it simply can't draw those peak amps (is that back emf?) like it can at 26mph. 39v will push the wheel to 33mph on a downhill, but it won't produce the watts at that sort of rpm, hence the realistic max at 30-32mph. In the summer I was riding a nice tailwind on a flat road at 32mph constant with a tiny 14amp peak limit, same 36v battery. Tailwinds kick ass.

Bottom line is that with 120% speed setting, the 6 turn Mac would be your best choice for a hub motor on 36v to reach near 60kph. Just don't expect to average that sort of speed or do it up low grades / into a headwind / super upright position.

I did get mine to 37mph no pedal, on 48v lipo at 21amps or so.

Oh, and cold weather will lower your speed. I first noticed this in my road cycling days.