Is 250w enough power for modest speed up steep hills

[PH]

PH I just had an interesting thought re your Bosch 250w motor, is the 250w a continuous or peak rating?

The 250w will be the maximum continuous rating, that's what the regulations say, that how it is with all E-bikes. I don't need to know any of the other stuff, just that it conforms to those regulations, which allow it to be more than adequate.

BTW friend in Switzerland is big into ebike's and looking at there legislation ebike are skill/age limited not power,

I'm pretty sure Switzerland has the same regulations as the UK, that is two classes - the one we think of as E-bikes and Speed Pedalecs, the latter requiring registration and treated more like a moped than a bicycle. They're not popular in the UK, though there are a few dealers offering them
https://urbanebikes.com/collections/spe ... /s-pedelec

[imk123]

Hello
Re the Bosch 250watt motor.
How do we know it is 250w as i just found these pages and no mention of Bosch motor power, just torque.
https://velorution.com/journal/a-guide- ... -displays/
https://www.wearethecyclists.com/brands ... rs-review/
Only mention of watts is in the battery rating.
Do Bosch get away with not mentioning there motor output as they are a large EU company.
And are pulling the wool over the eyes of our legislators, is this another VW/Audi emissions scandal in the making
Or they have a more powerful lobby than the likes of Bafang etc.

Anyone have a Bosch bike and like to measure the amps under full load, would be interesting to know the truth

[PH]

How do we know it is 250w as i just found these pages and no mention of Bosch motor power, just torque.

They have a website:
https://www.bosch-ebike.com/en/stories- ... s-an-ebike

[imk123]

How do we know it is 250w as i just found these pages and no mention of Bosch motor power, just torque.

They have a website:
https://www.bosch-ebike.com/en/stories- ... s-an-ebike

So did VW/Audi and they lied!

[hemo]

Knowone mentions the current of the mid drive motors that output some 800 - 850w as often quoted, as they are supposedly 36v systems we can assume then that the controllers are rated at 23 - 25a to amass this high wattage.
Hub motor systems don't mess with this the controllers clearly state the operating current, which is often 7a for a 250w run of the mill hub. 7w x 36v is 252w. We also know that these controllers can out put temporary twice the stated current but often the controllers will get too hot hence the temporary usage.
Woosh fo example use 9 or 10a controllers for there bikes with 250w hubs. The reg's are a bit of an ar** as there is no rating stated for controllers but only that motors are rated for 250w continuous, they don't state or say one can't push more throught them.

[stodd]

Woosh fo example use 9 or 10a controllers for there bikes with 250w hubs.

Are you sure on that?
Their kits mostly quote 17amps (Limit current (max. continuous)). Even 18a on the fairly basic XF07.
I can't see the equivalent specified on the bikes.

[Bonzo Banana]

I think the only ebikes that don't go beyond around 250W maybe 300W peak are those very cheap 20" wheel ebikes that have a 24V system and really the motors nominal wattage is about 160W perhaps 140-180W and they peak about 50% above that because that is all their small battery packs can provide. I think a typical hub motor and lower performance mid-drive motors maybe peak at around 500W and then you have the e-mountain bikes which can peak at close to 800W for short periods just to get up very steep inclines.

It should be pointed out that most controllers are DC to DC converters, voltage is speed and current is torque so the more torque you need the slower lets say a hub motor will get as its dropping voltage and increasing current. So what was 36V output could actually drop to lets say 12V or 6V but with the current much increased. That's how controllers move between torque output and speed output. So not only does a 48V setup have greater capacity for speed but it can have much higher current at low speeds. So motors are variable torque as well as speed and then of course the gearing of the bike also has similar controls if a mid-drive motor.

I didn't know that mobility vehicles are not limited by wattage only speed, we so need that applied to ebikes. The EU law is a farce and now outside the EU we could write a much better laws relating to ebikes. For example the old UK ebike law which was dropped in 2016 to fall in line with Europe where you still had the same assistance speed of 15.5mph but could use a twist and go throttle. This is so much safer in urban traffic as pedelecs can surge with cadence sensors where as a throttle gives you much finer and safer control just like a car. You can stop and stop pedelling when you want but the throttle gives you great control and you don't then have to rely on brake sensors. It's simpler and safer. Surely we could re-instate that law which is much more sensible and also helps people who are really struggling to cycle themselves but may be capable of it slowly. As it is there are many ebikes on the road that have that which were purchased before 2016 but can't currently be sold new but still legal to use if you have them.

[Nearholmer]

Question is, is 250w enough to pull bike and 70kg me up a steep hill with only modest peddle input

The answer is still “yes”, slowly, but “yes”.

Reading some of the rest of this discussion, I wonder whether some users need to opt for e-mopeds to get the performance they want/need.

The whole point of an e-bike is that it’s power capabilities are meant to bear some resemblance to the power capabilities of a human being pedalling an ordinary bike. If their power capabilities markedly outstrip that, they become a different thing, and it’s only right and proper that they have their “bike privileges” (no insurance, tax, helmet, ability to use shared-use paths, bridleways etc) removed.

I suppose there might be a case for developing a controller algorithm, and legal framework, that more closely models the power capabilities of Mr & Mrs Average pedalling an ordinary bike, which would permit short-term excursions above 250W, but probably have a lower continuous rating.

There might also be a case for making e-mopeds of the “more powerful than a cyclist, but still pretty weedy” kind cheaper to tax, free even, and removing the obligation to carry third party insurance, but if that was to be done I’d personally still want to see them registered and carrying an identifying plate/number, or some other means introduced to keep them off paths that they shouldn’t be on.

[Bonzo Banana]

Question is, is 250w enough to pull bike and 70kg me up a steep hill with only modest peddle input

The answer is still “yes”, slowly, but “yes”.

Reading some of the rest of this discussion, I wonder whether some users need to opt for e-mopeds to get the performance they want/need.

The whole point of an e-bike is that it’s power capabilities are meant to bear some resemblance to the power capabilities of a human being pedalling an ordinary bike. If their power capabilities markedly outstrip that, they become a different thing, and it’s only right and proper that they have their “bike privileges” (no insurance, tax, helmet, ability to use shared-use paths, bridleways etc) removed.

I suppose there might be a case for developing a controller algorithm, and legal framework, that more closely models the power capabilities of Mr & Mrs Average pedalling an ordinary bike, which would permit short-term excursions above 250W, but probably have a lower continuous rating.

There might also be a case for making e-mopeds of the “more powerful than a cyclist, but still pretty weedy” kind cheaper to tax, free even, and removing the obligation to carry third party insurance, but if that was to be done I’d personally still want to see them registered and carrying an identifying plate/number, or some other means introduced to keep them off paths that they shouldn’t be on.

It's very easy to go beyond the capabilities of an ebike's motor on any legal ebike, they only assist to 15.5mph and yet you could be cycling at 20-30mph on the flat and going downhill at 40mph or more. If you are happy to trundle along at 15.5mph or less you can have permanent assistance but most people I would assume spend a good amount of time on an ebike with no assistance at all at least for ebikes mainly used on the road. I guess e-mountain bikes would typically have a much greater proportion of time with assistance on.

[Nearholmer]

All true, but not quite what I’m driving at.

What I’m driving at is that 250W continuous assist rating is plenty enough for something that is supposed to resemble an ordinary bike, whereas I read many people advocating more assist power, but seemingly very reluctant to embrace e-moped.

As to how much assist riders use, it clearly ranges very widely.

A high proportion of the obviously e-bikes that I see about are ridden by older, or stouter, or older and stouter, people who are clearly using a fair bit of assist - you can easily see that their legs are ‘going round for the sake of it’, with the bike trotting along out of all proportion to effort being deployed. We have vast amounts of shared-use paths here, so people use e-bikes as super-duper-light mopeds to make short trips, where battery duration is no issue even on full assist, shopping etc, these are ‘utility riders’, not ‘cyclists’ out for exercise.

The less obviously e-bikes, typically chosen by ‘cyclists’, I have no idea about assist levels chosen, because many of those are virtually indistinguishable from ordinary bikes. I just assume that everyone who overtakes me going up hill is fitter than I am, which I’m sure isn’t wrong!

[imk123]

Why do " ‘cyclists’ out for exercise." need Ebikes?

[Jdsk]

Why do " ‘cyclists’ out for exercise." need Ebikes?

There are many posts in the archives describing how some assistance allows people on bikes to go further, to get to attractive areas, to climb hills and to ride with others.

And as far as we know people riding eBikes are getting more exercise than they would be otherwise.

Jonathan

[Nearholmer]

I can foresee the day when plugging very slowly up hills might cease to be a satisfying challenge, and become the thing that starts limit the sort of bike rides I choose, in fact for the month after covid I had a horrible worry that day had arrived, so I do “get it” for people who are becoming ‘very mature’ and/or live with health-related resurrections (that is a weird auto-correct. I think I’ll leave it).

[toontra]

200-250w is roughly what I generate on moderate or steep climbs at a reasonable speed on my non-motorised bikes according to their power meters, so I assume that translates roughly into what's required from a motor.

[richtea99]

Why do " ‘cyclists’ out for exercise." need Ebikes?

Why do " ‘cyclists’ out for exercise." need gears? What's wrong with a singlespeed. Are you weak or something?

Next random question please.