First ride on the Rocky Mountain X503 = 42mph

L

Lowell

100 kW
Joined
Jan 12, 2007
Messages
1,695
Location
Vancouver
72-73v indicated on the DrainBrain and all the aero of a brick. Helmet, loose jacket, vest, jeans. Bike would probably hit 50mph+ as is with proper clothing and tucking tight over the bars. Will be finding out soon enough. In hindsight, I'm glad I didn't get the 504 motor as I would pretty much be maxed out on speed right now, and the torque on the 504 at 72v is more than acceptable.

Bike is an old Rocky Mountain Experience that someone gave me for free. Pretty much all stock except for brake pads, and I removed the chain drive for testing with 100% electric power. (partly because that was the easiest way to bolt on the X5 hub too)

Crystalyte 503 with a 72v 35 amp controller. Batteries were a cobbled together (2) 24v 18ah NiMH, and a 36v 8ah nicad pack all in series. Tomorrow I'm going to add another 36v 8ah nicad pack in parallel to try and minimize voltage sag and allow a longer test run. If that works out to my liking, I'll buy a pair of matching battery packs, as the ones I'm using are just what someone loaned to me to test with.
 
43mph? Yikes!
Good thing you installed new brake pads.

What kind of NiCd's are you using? What do you use to charge them?
 
I've noticed that people here have been skeptical that these machines can really go as fast as 42+ mph and it's good to see others reaching those speeds. My 86 lbs of SLA batteries have been able to get me to 46 mph and there's plenty of areas to improve on that. Below is a chart for what I "expect" my future bikes 8 speed gearing to give me for speed. Can you imagine a 57.2 mph top speed?

:arrow: Great job and welcome to the "Over 40 mph" Club!

(I hope to be the first on this board to join the "Over 50 mph" Club)
 

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Oh yeah... we all need to get full face motorcycle helmets and some good protective clothing if we are going to be doing this stuff. Something like motorcycle "body armor" is cheap and you can wear it without leathers to stay cool. This is what I'm going to get. Kinda gives you a "Darth Vader" look, but that's okay. (I wish they came in different colors... I might actually spray paint the plastic parts on mine a lighter color to keep cooler in the summer sun and just wear it alone)

3e_1.JPG
 
Hey, lowell, congrats on joining the 72V x5 club! I didn't catch your wheel size -- 26" ? Are you riding in Vancouver, BC, or Vancouver, WA?

I'm more a torque guy than a top speed guy -- sitting fully upright on an upright bike, my 5304/24" has a top speed of 44mph at 80 volts. So you're right about the 5304 being about maxed out at 42mph.

I've only ever gone 38mph (which is plenty fast enough for me). I just returned from a ride where I hit 35mph up a ~2-3% grade -- the bike still had very impressive torque left.
 
Ypedal said:
wowzers.....

I recomend a motorcycle helmet.. cloves.. football padding maybe ? :D

How many amps at this speed ?

I ran an X502 at 48v in a 20" wheel and made it to 45 mph...... with 12 ah SLA's.. at 72v the unloaded speed must be something else.. yikes.
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I didn't check the amp draw, but the speed controller limits draw to just over 35 amps. Unfortunately the DrainBrain only has 2 digits for the speed limiter field, so 99km/h is the max unloaded speed unless you fool the speed reading.
 
fechter said:
43mph? Yikes!
Good thing you installed new brake pads.

What kind of NiCd's are you using? What do you use to charge them?
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Batteries and chargers are all from Ebikes.ca.
 
xyster said:
Hey, lowell, congrats on joining the 72V x5 club! I didn't catch your wheel size -- 26" ? Are you riding in Vancouver, BC, or Vancouver, WA?

I'm more a torque guy than a top speed guy -- sitting fully upright on an upright bike, my 5304/24" has a top speed of 44mph at 80 volts. So you're right about the 5304 being about maxed out at 42mph.

I've only ever gone 38mph (which is plenty fast enough for me). I just returned from a ride where I hit 35mph up a ~2-3% grade -- the bike still had very impressive torque left.
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Vancouver, BC. Wheels are 26", and the rear tire is a fat knobby. I'm going to upgrade the tire to something more appropriate for high speed use. Any suggestions?

I'm going to add more voltage, and maybe tweak the controller current limit up to 40 amps. If I end up upgrading the controller FETs to 150v, I'll definitely be trying 120v with more current, but that will have to go along with lithium batteries most likely.

The short term plan is a solid 84v and then tweak the aero as needed to break 50mph.
 
Good Job
 
Good work

You will need good batteries on your bike to hold any distance at over 40mph though thats the only bad thing it will suck amps and the jump from 40 to 50 mph is a huge increase.

I like to test to see how fast they can go but don't like to use the bikes day to day over 30mph as the brakes and the rest of the bike just isn't man enough, I already go through 1 x set of brake blocks every couple of weeks and my wheels are black with dust all the time.

That body armour is a good Idea, I had a fall before xmas and I am still hurting, I broke a rib and sneezing hurts real bad, one thing my full face helmet saved the day though, I would have a very bad scar on my face if I had been wearing a normal cycling helmet and I doubt I would be here if I had had no helmet on at all, I am not kidding either my head hit down hard.

A good full face helmet with an e-bike that can do over 20 is a must and should be e-bike law if you like, of course its entirely up to the rider but I dont want anyone to get hurt or killed.

Play safe and stay safe..keep up the excellent works, vids and pictures next please!

Knoxie
 
The power draw sure does jump up. 45km/h is right around 20wh/km on the DrainBrain, and after resetting, 60+ showed just under 40wh/km. At 40wh/km, I'll only have a range of 30km with an 80% discharge :(

When you say brake blocks, do you mean disc brake pads? I don't have a front disc yet, but there will be some sort of heavy duty brakes added soon. No rim brake can stop a heavy e-bike safely from these speeds.
 
knoxie said:
That body armour is a good Idea, I had a fall before xmas and I am still hurting, I broke a rib and sneezing hurts real bad, one thing my full face helmet saved the day though, I would have a very bad scar on my face if I had been wearing a normal cycling helmet and I doubt I would be here if I had had no helmet on at all, I am not kidding either my head hit down hard.
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Speaking as a long-time motorcyclist I'm with you 100% on the helmet at those speeds. Full face is a very good idea too. Of course you replaced your helmet now that it's been belted on the ground right Knoxie? :wink:

As for body armour, it's a bit of a contentious issue. For me personally, abrasion resistance is the main thing for protective gear. In typical road riding, if you step off you're going to slide (especially at the speeds you guys are talking about). Tarmac is very abrasive, fortunately I've not done that much tarmac surfing, but I can tell you that my cordura jacket protected my arms and survived with barely a scratch, while my denim jeans lasted about 2 seonds. 2 seconds doesn't sound like much until you're sliding along the road :lol: This would have been at about 45-50mph, I've got a decent scar on my knee to show for it.

Armour has it's place, but basically if you hit something hard enough, your bones will break no matter what.
 
I was actually looking at some of the downhill mtn bike helmets today. I *could* wear my motorcycle helmet I guess, but was looking for a happy medium between a full faced motorcycle helmet, and a typical bicycle helmet.
 
I'm going to upgrade the tire to something more appropriate for high speed use. Any suggestions?
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I'm happy with my Maxxis Hookworms. They aren't kevlar belted, so I bought the kevlar separately and installed it along with super-thick downhill racing tubes. 900 miles and no flats or other tire/tube problems yet. Two broken 13 gauge spokes though. If you get a chance, re-lacing with 12 gauge spokes would be good (the x5's usually come with 13 gauge). As I didn't want to take the wheel off, I've been carefully changing spokes as they break.

To hold 50 mph (80.6 kph), if you're in a normal upright position and not tucked in a ball like Safe, you'll need 3500 watts at the pavement. Figuring ~80% efficiency, that's 3500 watts/0.8 = 4,375 watts input.
http://www.kreuzotter.de/english/espeed.htm
I've found this calculator and calculation method very accurate, within 2mph or so of real-world power use.

So to hold 50mph on flat pavement, no added wind, upright position on an upright MTB, 120 volts and 36 amps or 110 volts and 40 amps should do it.
 
Well I got the extra battery in, and did a quick indoor test. 40.8 amps at 82.5v at full load. Battery voltage straight off the chargers, with no load is 96v, so the controller should be fine. (it's raining pretty hard outside, so no high speed riding)

So 3366w input, and I figure 2700-2900w output maybe? That should break 50mph by leaning down over the bars... will find out as soon as the roads are dry.
 
Well I got the extra battery in, and did a quick indoor test. 40.8 amps at 82.5v at full load.
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That's interesting...almost 41 amps with the 35 amp controller as measured by a drainbrain?

I've got the same controller and an ammeter on the handlebars full-time. 35 amps is the most my meter ever reads.

So 3366w input, and I figure 2700-2900w output maybe?
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80% efficiency would be ~2700 watts, giving a predicted top speed, sitting upright, of 45mph, and... 50mph in a tuck position!

It'll be interesting to see how close you actually get.
 
The current limiter in those controllers is not exactly what I would call precision. There could be quite a variance from on to another. That does seem a bit high though. The FETs might become unhappy on a steep hill.
 
What do you guys think of adding a fan to the speed controller, similar to what the chargers come with? With a dirt filter on the inlet, it could only be a good thing, no? Or is heat buildup not the issue with blowing up speed controllers?
 
Heat can be an issue, especially during the summer. The heat is trying to come off the side that has all the screws in it. This is the bottom on most of them (stupid). It's real easy to take both end plates off and turn the whole box over so the screws are on top now.

Another thing that would really help would be some fins. I thought about taking some 1/2" U channel and using the existing screws to bolt 3 sections of channel on, which would form 6 fins. Use heatsink compound.

A CPU cooler would help if it was bolted to the case. Again, this would need to be on the side with all the screws. You can take out some screws if they are in the way.

The stock FETs are really sort of sucky, but at 35 amps, they seem to hold up fine. They have a high on resistance, so under extreme load, they start throwing off a lot of heat. I got mine to trip on overtemp after riding for about 15 minutes (this was before replacing all the FETs).

With upgraded FETs, the thing barely gets warm.
 
knoxie said:
A good full face helmet with an e-bike that can do over 20 is a must and should be e-bike law if you like, of course its entirely up to the rider but I dont want anyone to get hurt or killed.
Click to expand...

The law is already in place. A moped or motorcycle, be it illegal or otherwise requires a helmet under the law. Even legal setups require at least a bicycle helmet.

Locally while there's no helmet law for bicycles, legal power assist bikes that are restricted to 20 mph require a helmet be worn at all times.

It's a bit convoluted since even though an ebike with under 500W is classed & treated a regular bicycle under the law, the helmet requirement is in a separate section of the Transportation Safety Act. You have to dig around to find it & suddenly for the purposes of that particular section, the ebike is redefined from bicycle to 'power bicycle'.

I think this holds true across the country, as Canada is a nanny state & it may be the case in other parts of the world as well, so best to check into it.

FWIW since the law is kinda obscure, I doubt any cops would even be aware of it. But as the number of ebikers increases, particularly illegal setups that will get the motoring publics' nose out of joint, at some point the polis will be getting a refresher on the finer points of power bicycle law I'm sure.
 
Don't forget to put the "500W" sticker on your X5 :lol:
Most cops don't carry a Fluke meter, let alone know how to use one.
 
Yeah, but if you blow by them going 45 or 50 mph, they're not gonna give a rats a$$ about the watts. They do know how to work point-n-shoot gizmos such as lidar & the like. At that point they have their choice of a smorgasboard of offences they can choose from, depending on how much you open yer yap. If you have a proper helment they tend let you off with a caution, so best do yourself the favour all round.
 
They [cops] do know how to work point-n-shoot gizmos such as lidar
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:)
and a couple others if yer tryin' to bolt into the forest or sumptin'
 
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