This site won't allow me to search for W-h/km as it says it contains too many common terms. Okay but wikipedia found it as a common rating for e-batteries. What I want to know is how does it translate to Ah amp hours. Specifically what is a 24 volt battery spec'd at: "Continuous theoretical driving range: 11.7 W-h/km and a Maneuvering theoretical range: 18.6 W-h/km? The motor is a 250 watt.
definition of W-h/km please
- Thread starter sometrike
- Start date
teslanv
1 MW
Wh/km and wh/mile are terms used to describe the efficiency of a bike with an electric motor.
To calculate the capacity of a battery in watt-hours, just multiply the nominal voltage by the capacity in amp hours. So a 24v 10ah battery would have 240 watt-hours.
To find your range, of a given battery, divide the battery capacity in watt-hours by the efficiency of the bike/motor.
A common efficiency figure might be 30 wh/mile so the 240 wh battery would give the bike a range of 8 miles.
To calculate the capacity of a battery in watt-hours, just multiply the nominal voltage by the capacity in amp hours. So a 24v 10ah battery would have 240 watt-hours.
To find your range, of a given battery, divide the battery capacity in watt-hours by the efficiency of the bike/motor.
A common efficiency figure might be 30 wh/mile so the 240 wh battery would give the bike a range of 8 miles.
Ypedal
100 TW
wh/km is the electric equivalent of miles per gallon from fuel cars.
a typical 200 Lb rider, on a light weight lower power, slow moving ebike, will generally average 10 wh/km
so, say 24v 10ah = 240 wh ... should deliver 24 km range per charge.
the heavier you are, the faster you go, the less you pedal.. the more you burn......
a typical 200 Lb rider, on a light weight lower power, slow moving ebike, will generally average 10 wh/km
so, say 24v 10ah = 240 wh ... should deliver 24 km range per charge.
the heavier you are, the faster you go, the less you pedal.. the more you burn......
Thank you, your responses were much more clear than my question. What I am trying to do is find a light weight battery comparable or better to the one I already have referenced above, which I now see is a 10 Ah. I'm thinking this one is equal or better, any thoughts? http://www.bixnet.com/24v9ahhipoli.html Damn they call it an 11 AH battery, but look at the url. There is a 9ah in it.
dogman dan
1 PW
The simple answer is two batteries. Buy one, and if it performs well for you plan to buy a second one. Half way along your trip, you simply swap to the fresh pack.
The lightest type of battery will be lithium manganese type, Lifepo4 is slightly heavier and much bigger. lithium cobalt is small and light but risky compared to limn or lifepo4.
Double your range by having two batteries. However, if you just want half more range, then a 15 ah size pack is what you need. The boxed battery tends to be a certain size. It's a matter of what fits frames, what is not too much weight for rear racks, what is not just too high priced for a new rider to consider paying. So lots of 10 ah size stuff out there, only about 300-400 watt hours.
Other battery retailers sell batteries with only shrink wrap protection. They tend to be available in a much wider range of sizes. Then you build a cheap container to protect it, and carry it in a rack or frame bag.
Once you get the hang of it, mentally making the calculation to wh is easy. Then thinking in wh, you get fair comparisons of battery capacities. And wh/km is easy too, if you have a wattmeter to measure the watt hours used. You just divide your wh by the distance. Or you can do a close enough calculation if you use the whole battery, and you know it should have 280 wh. Measure your actual voltage, then multiply times rated capacity.
The lightest type of battery will be lithium manganese type, Lifepo4 is slightly heavier and much bigger. lithium cobalt is small and light but risky compared to limn or lifepo4.
Double your range by having two batteries. However, if you just want half more range, then a 15 ah size pack is what you need. The boxed battery tends to be a certain size. It's a matter of what fits frames, what is not too much weight for rear racks, what is not just too high priced for a new rider to consider paying. So lots of 10 ah size stuff out there, only about 300-400 watt hours.
Other battery retailers sell batteries with only shrink wrap protection. They tend to be available in a much wider range of sizes. Then you build a cheap container to protect it, and carry it in a rack or frame bag.
Once you get the hang of it, mentally making the calculation to wh is easy. Then thinking in wh, you get fair comparisons of battery capacities. And wh/km is easy too, if you have a wattmeter to measure the watt hours used. You just divide your wh by the distance. Or you can do a close enough calculation if you use the whole battery, and you know it should have 280 wh. Measure your actual voltage, then multiply times rated capacity.
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