500w e bikes now legal in NSW

[Brendan H]

Gday .

I am always checking ebike laws in NSW. Seems the rules and /or wording in those rules is constantly changing.

So to my surprise ,when I checked this evening, I found that ebikes in NSW are now allowed a motor of 500w continuous rating. That means the motor can run at 500w continuously forever without overheating . So probably at 1000w for a minute would be the upper limit.
This replaces the 250 w continuous rule.
The motor must still cut out at 25kph.
Much better for uphill work.
I am happy to see that the 200w motor rule still has no speed limit.
Here is the NSW Rule explained.
https://roadsafety.transport.nsw.gov.au ... ycles.html

[Comedian]

Better for cargo bikes too.

Will be very interesting to see how this plays out. How it spreads to other states, and whether manufacturers change what they are supplying or whether they just change the "200w" stickers to "500w"

Contrast this with QLD scooter laws where there is no maximum power. It's quite common for scooters to have north of 2000w

[Thoglette]

I had to do a little homework (as I'm not the sort of cyclist who counts watts)
A little reverse engineering of Gradients and cycling: how much harder are steeper climbs? (The Climbing Cyclist) shows that the change from 250W to 500W will allow the following increase in gradient at 25kph for the following bike+rider masses

80 kg 2.25% -> 7%
90 kg 2% -> 6%
100kg 1.8% -> 5.5%


Now, if you dial in another (lazy) 100W to keep the pedals turning you get 8.75%, 7.75% & 7%
It's almost linear, so 200kg and you're able to do ~3.5% at 100W of pedaling

[Comedian]

I had to do a little homework (as I'm not the sort of cyclist who counts watts)
A little reverse engineering of Gradients and cycling: how much harder are steeper climbs? (The Climbing Cyclist) shows that the change from 250W to 500W will allow the following increase in gradient at 25kph for the following bike+rider masses

80 kg 2.25% -> 7%
90 kg 2% -> 6%
100kg 1.8% -> 5.5%


Now, if you dial in another (lazy) 100W to keep the pedals turning you get 8.75%, 7.75% & 7%
It's almost linear, so 200kg and you're able to do ~3.5% at 100W of pedaling

I am unclear how they calculate these power figures. Somehow some watts have more effect than others. A bosch performance line bike has heaps more mumbo than an Active line. Both 250w.

Rating electric motors seems a bit arbitrary.

[brumby33]

How's this going to effect the battery life or useable life per battery charge? Will it half the distance or worse? what size battery would you need to do the same distance?

[Comedian]

How's this going to effect the battery life or useable life per battery charge? Will it half the distance or worse? what size battery would you need to do the same distance?

Will it actually make any difference or will they be exactly the same motors but with "500w" written on them?

[Thoglette]

Rating electric motors seems a bit arbitrary.

Yup. In theory, the rating is that amount it can produce without overheating (or blowing up) in a steady state. The ambient temperature has a big impact on that number.

As does the number of hours you can do that rating without wearing it out. Or what percentage of your production run will actually achieve those numbers.

In practice there'll be a pile of optimism in some people's ratings. And lots of conservatism in others (hello Bosch).

[Thoglette]

How's this going to effect the battery life or useable life per battery charge? Will it half the distance or worse? what size battery would you need to do the same distance?

If you're going zero-to-flat-out all the time it'll halve battery life. Or double the battery size.
If you cruise around on the flat at 25kph all the time (and using less than 250W to do it), then one might get the same-ish range. See the link in my previous post - you should only need a few dozen watts to cruise along at 25kph.

Will it actually make any difference or will they be exactly the same motors but with "500w" written on them?

Depends on whether the limit was the motor or the motor controller. Or the warranty period (see my previous comment)

Practically, there'll be changes somewhere. In the bits that cost money (otherwise the value engineer will get fired)

[Comedian]

How's this going to effect the battery life or useable life per battery charge? Will it half the distance or worse? what size battery would you need to do the same distance?

It'll halve battery life. Or double the battery size

Will it actually make any difference or will they be exactly the same motors but with "500w" written on them?

Depends on whether the limit was the motor or the motor controller. Or the warranty period (see my previous comment)

Practically, there'll be changes somewhere. In the bits that cost money (otherwise the value engineer will get fired)

If they do really double the power output I can't see it halving the battery range assuming the bike is still limited to 25kph. The amount of time you will benefit from the extra power would be a fraction of the operating time. Heavy bikes like cargo bikes might be more affected but I'm sure they'll be grateful for the extra power.

[Thoglette]

If they do really double the power output I can't see it halving the battery range assuming the bike is still limited to 25kph. T

Right you are: I've corrected my post (but you beat me to it).

This mob claim 200W will get you about 35kph on a normal drop bar road bike.

Which, for someone who doesn't count watts sounds about right (When in MAMIL mode I have to work to keep up with a 250w e-thing up hills but then ride away on the flats at 30ish kph )

[blizzard]

I had to do a little homework (as I'm not the sort of cyclist who counts watts)
A little reverse engineering of Gradients and cycling: how much harder are steeper climbs? (The Climbing Cyclist) shows that the change from 250W to 500W will allow the following increase in gradient at 25kph for the following bike+rider masses

80 kg 2.25% -> 7%
90 kg 2% -> 6%
100kg 1.8% -> 5.5%


Now, if you dial in another (lazy) 100W to keep the pedals turning you get 8.75%, 7.75% & 7%
It's almost linear, so 200kg and you're able to do ~3.5% at 100W of pedaling

I am unclear how they calculate these power figures. Somehow some watts have more effect than others. A bosch performance line bike has heaps more mumbo than an Active line. Both 250w.

Rating electric motors seems a bit arbitrary.

The motor torque rating is much more important uphill than power. A 250w w/ 60nm is much slower up hill than a 250w w/ 90nm.

[skyblot]

The motor torque rating is much more important uphill than power. A 250w w/ 60nm is much slower up hill than a 250w w/ 90nm.

The power is at least as important. Power is the ability to do work, 750 watts is about 1 horsepower, and 1hp is 550 foot pound per second (move 550 pounds, 1 foot, in 1 second). Sorry I don't naturally relate that to the metric system...
You can put heaps of torque onto the pedals, but until they move - no work has been done.

The combination of power, torque, and the bikes gearing will determine how it performs in the real world.

Interestingly, almost all electric motors produce peak torque at zero RPM but of course do no work in that condition.