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Backpacker Joe
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Backpacker Joe
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PostSun Dec 26, 2021 2:23 pm 
Chief Joseph wrote:
I do want an E-bike and that one looks amazing, but no way I could justify that over my dream bike, a Husqvarna dual sport motorbike and I could get a good used one for about the same price.
I wouldnt disagree CJ, if I still had a drivers license.

"If destruction be our lot we must ourselves be its author and finisher. As a nation of freemen we must live through all time or die by suicide." Abraham Lincoln

Cyclopath
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Cyclopath
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PostTue Feb 08, 2022 2:31 pm 
This is probably a dumb question, but why is it useful to think of battery capacity in terms of watt hours? As opposed to simply Jules? You're drawing a different number of watts every second in response to changes in wind, hill grade, etc.

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Tom
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PostTue Feb 08, 2022 2:44 pm 
Amp hours are more typically used for batteries to define capacity. Watt hours is just a convenient way to compare ebike battery pack capacity since different bikes use battery packs with different voltages, so amp hours aren't comparable. To get watt hours you multiply volts by amp hours.

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Cyclopath
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PostTue Feb 08, 2022 8:21 pm 
I understand eBike batteries being rated like all other batteries, that makes sense. I just don't understand why they're rated in a number with two components like watt hours or amp hours, when joules seems like it makes more sense. And I'm sure it's not because the rest of the world is full of idiots who aren't as smart as me, so I've got to be missing something here. As a cyclist I'm interested in the # of calories I burned and tacos I earned. smile.gif Calories are the same as joules, I could say I burned 720 kCals, or did 100 watt hours for two hours. We all use the first one because it's simpler. And it seems like me getting pooped pedaling an acoustic bike beyond my endurance is close enough to running the battery down.

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Randito
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PostTue Feb 08, 2022 9:29 pm 
Cyclopath wrote:
when joules seems like it makes more sense
Joules are metric /eurotrash unit you can't think Yankees would be willing to use it? But even using imperial units, KWH (Kilowatt-Hours) would be the unit of choice. But battery makers seem to prefer state battery capacity in Amphere-Hours and make you multiply by volts to get watt-hours and divide by 1000 to get Kilowatt-hours.

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Tom
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PostTue Feb 08, 2022 10:28 pm 
Eh, they are batteries, used for more things than ebikes. You want your power drill battery capacity in joules so you can figure out how many calories you could have burned doing it by hand? How about your computer or phone battery? Measured in what? Brain cells wasted? lol.gif

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BigBrunyon
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PostTue Feb 08, 2022 10:38 pm 
The problem with the E-BIKES is that you get these individuals driving e-bikes at reckless sustained speeds upwards of 40mph up these long, steep trailhead approach roads. Gives an unfair advantage!!

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neek
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neek
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PostWed Feb 09, 2022 5:00 am 
Joules and watt-seconds are the same (kg * m^2 / s^2). 1 J = 1 W s. But since a watt is also volts * amps, it's used in electrical settings. It wouldn't sound right to talk about your 100 joule/sec light bulb. What would make more sense would be to toss Calories (kcal) and use joules for food energy as well. It's weird to me that batteries are rated in amp-hours, since most people don't care about volts and just want to know how much energy they can store.

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Cyclopath
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PostWed Feb 09, 2022 10:21 am 
Tom wrote:
Eh, they are batteries, used for more things than ebikes. You want your power drill battery capacity in joules so you can figure out how many calories you could have burned doing it by hand? How about your computer or phone battery? Measured in what? Brain cells wasted? lol.gif
I don't understand how labeling them in amp hours (or use in watt hours) makes any more sense than in joules. If I use a power drill at 10,000 watt hours for 7 minutes, those numbers are meaningless and take a lot of extra brain cells to make sense of. How does that make things better? Not trying to be argumentative, this has never made sense to me.

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Cyclopath
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PostWed Feb 09, 2022 10:38 am 
neek wrote:
Joules and watt-seconds are the same (kg * m^2 / s^2). 1 J = 1 W s. But since a watt is also volts * amps, it's used in electrical settings. It wouldn't sound right to talk about your 100 joule/sec light bulb.
To back up for a second. A joule is a unit of work in the physics sense of moving mass over distance. A watt is a speed, it's the rate at which work is getting done. 1 watt = 1 joule per second. (A calorie is the amount of heat needed to raise the temperature of 1g water by 1* C.) A lightbulb makes sense to rate in watts, because it uses the same amount of power constantly. You can't know how much total energy it will use without knowing how long it will be in use, but you know that going through 100w makes it brighter than the 60w one. Labels are just tools to help us make sense of things, it's ok to use the one that's easiest in a situation. I'm asking what situation watt hours are suited for. I asked Google how much total energy do humans use in a year, the answers came back in hundreds of thousands of terawatt hours, and in BTUs. Wut?

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Tom
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PostWed Feb 09, 2022 2:42 pm 
Cyclopath wrote:
If I use a power drill at 10,000 watt hours for 7 minutes, those numbers are meaningless and take a lot of extra brain cells to make sense of.
Why are the numbers meaningless? In the case of a drill battery, after multiplication of watt hours by 3600, what would you use joules for? Why aren't car gas tank capacities measured in joules? Would that make it easier for us to figure out something useful? I got the impression you seem to think joules would be preferable for ebike batteries because you want to compare to how much total assist the battery can provide. Similar to a car, an ebike's efficiency is going to depend on quite a few factors, so I don't know what joules or kpj or mpj tells you that watt hours or gallons or mpg or mpwh doesn't. Also, keep in mind that watt hours calculated by multiplying rated volts x ah is just a loose representation of capacity, and it overestimates. As cells discharge the voltage drops non-linearly from a higher voltage (than the battery is rated) to a lower voltage, and more so with a higher discharge rate, so a 1000 wh ebike battery isn't necessarily 3.6 million joules (or 860 kcal). Even if you had an exact measurement considering all the cells in a fully charged state, what if some of the internal cells are substandard or unbalanced? How old is the battery, and how has it been used, stored and cared for? Also, you're not going to be starting with a fully charged ebike battery every time. I never store or charge my ebike battery beyond 80% for long term health unless I'm balancing the cells and planning to ride soon. Like many riders I also monitor voltage rather than display % to better estimate how much capacity I have left.

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Cyclopath
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PostWed Feb 09, 2022 9:18 pm 
I'm not wanting to change the labels on the world's batteries. I want to know what kind of situation makes the ones we use easier or more convenient. I'm sure there's a good reason, but I have not idea what it is. Just idle curiosity. Paying Seattle City Light for however many kilowatt hours I used in a month ... seems more confusing than it needs to be.

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Tom
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PostWed Feb 09, 2022 9:51 pm 
I would think kilowatt hours makes more sense to the average consumer than joules. If you left 10 of your 100 watt bulbs on for an hour, that consumes 1 kwh, no? I have a kill-a-watt meter somewhere and it was fun going around the house seeing how many watts various appliances use, but the novelty quickly wore off. More fun to ride the ebike and watch things play out, well, until you find yourself in a situation where you're trying to get up the last monster hill on the way home and the controller is nannying your low battery with a load of groceries on the rear rack.

Cyclopath
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RumiDude
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RumiDude
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PostWed Feb 09, 2022 10:00 pm 
"We are so thrilled about the uptake from our early-adapters within the first three weeks of pre-orders. It has exceeded our expectations. Zen Samurai is a premium, high performance e-bike designed for discerning enthusiasts, and we want to create a strong community to lead the transition to electric mobility. So, we are extending this exclusive offer of $1000 USD off until March 15, 2022." Zen Samuri Preorder I cannot vouch for this company so buyer beware. Rumi

"This is my Indian summer ... I'm far more dangerous now, because I don't care at all."
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Tom
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PostWed Feb 09, 2022 10:27 pm 
Should be a solid mid-drive, some reputable folks behind zen ebikes. The Samurai is more of a premium mid-drive offering with belt drive and IGH. They also have a lower priced rear hub drive Shatki that should be available for pre-order later this year. https://www.zenebikes.com/shakti For a budget mid drive I would consider this one. https://ride1up.com/product/prodigy/

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