Question for the Perth (Australia) e-bikers

[jonescg]

Just curious as to how much battery you'd need for an e-bike capable of Perth Hills to Curtin uni and back (or charge at work).

I'm keen to push for a sealed path which cuts through Mundy park and reduced the trip by at least 5 km. Gravity alone will demand 100 Wh worth of battery, so I'm guessing 15 Ah at 48 V might be a minimum?

 

[amberwolf]

What speed do you need to go?

How long is the total path?

What is the terrain like?

What are the wind conditions?

What is the weight of you, bike, etc?

What type of bike?

How much pedalling, if any?

Riding upright? Tucked? etc?

We can calculate out a basic minimum wh/mile and total minimum wh with the above information, if you don't get other responses.

 

[jonescg]

Thanks AW, I guess I was putting it out there hoping to hear from some long time Perth e-riders.

The route in question is this:

And the red circle denotes one of several new sealed bike paths I'd like to see from the hillside suburbs to the centre of town. The elevation drop is significant (for Perth :wink: ) and the GPE calculation suggests there's at least 100 Wh in overcoming gravity alone. The rest of the trip at 18 km is a good, long commute. And assuming 20 Wh/km, 360 Wh + 100 Wh = 460 Wh in total. If you had a 500 Wh battery you'd be in good stead, but I suspect a bit more might be handy for the ride home.

I live in the hills, and while it's a lovely place to live, it's poorly serviced for bikes. The main impediment being Welshpool road and its 80 km/h, dual carriageway nature being pretty unappealing for most cyclists. If we could carve a track down the hillside it makes the commute quite viable.

That said, I work in North Fremantle, which is 40 km away from home. The Ioniq makes light work of that.

 

[amberwolf]

Do you get much wind, at any time you'd ever be riding? You'd want to add enough extra battery to make up for that, too. As well as adding enough to cover required detours if a path is closed, etc.

 

[jonescg]

It can get windy, yeah. Through summer we have bitching hot easterlies and if we're lucky we cop the Freo doctor - a relieving sea breeze which never makes it as far inland as Kalamunda...

I should say, I used a combined e-bike mass of 120 kg, which is probably on the heavy side, but sensible.

It's been a while since I looked at a Cycle Analyst - equipped bike, but 20 Wh/km seems about right for some shared pedalling. I recall my Cell_Man ebike kit with a direct drive motor used to smash 50 Wh/km at full noise.

My wife has a drop-tube style ladies bike with a 200 W motor and 36 V, 11 Ah battery. I have a feeling it wouldn't be a comfortable bike for 36 km a day though.

 

[amberwolf]

Depending on the wind, and the aero of the bike, and the speed you ride at normally, a really stiff breeze can double (or more) the wh/km needed to get somewhere. (because it may nearly double the effective speed you're riding at, as far as air resistance goes).

A hard headwind could triple or more that wh/km, and may even overwhelm the power of the motor to even maintain speed.

Something to think about.