need help understanding the matching of the battery to the wheel.

[ScooterBronson]

Im looking at purchasing this E-wheel kit and I will need to get a battery for it The wheel is 26" 48 volt 2000 watt 20 ah fat front wheel kit. Now its my first time seeing 2000 watt, most I see say 1000 or 1500 watt. So is it deception or is it legit? And same for the battery, most say 1000-1500 watt but i did find a battery rated at 2000 watts. Is there a noticable difference between 1500-2000 watt. How would I go about testing them to confirm that they are as to what they are claimed? thanks, bronson

 

[biknut]

Sounds like a 48v battery with a 20 amp bms? 2000 watts doesn't tell us much, unless they mean 2000 watt hours. A 48v battery with 2000 what hours would be a really big battery of 41.66 amp hours.

 

[ElHegpah]

Rating a motor at "1000 watts" simply means that it will take that amount of power without melting. For HOW LONG is a question which is answered by advertisers, not engineers. Often the identical motor will be rated at 1000, 1500, and 2000 watts, just not for the same amount of time. Check the weight. Sustaining more power generally requires more physical mass, in similar designs. More pounds of iron and copper will soak up more heat. Put an oil fill and external heat sinks on a "1000 watt motor", and you can safely run 3000 watts for short periods. More if you live in a cold climate.

For a battery, it is a much more accurate measurement, but something of a moving target. Batteries degrade over time and loose capacity. Batteries can supply a large amount of amps, for a short period, but usually this will degrade them faster. Drawing a lower amount of amps will result in a battery with a longer lifetime, also greater useful capacity for an individual charge cycle.

Think of jogging for a long distance, or sprinting for a short distance. Then do both when you are much older. What is your capacity in these different situations? How does each different usage condition affect your total output?

 

[ScooterBronson]

thank you for answering my questions as they help me understand. What I have is an E scooter that has no pedals and is only powered by the hub motor and the battery that powers it. I have been operating a 36 volts 800 watt wheel powered with (3) 12 volt 20 Ah NiCad wired together (alot of weight). This was 10 years ago but now has only half the steam. When new I estimate 20 MPH top speed with 215lbs rider going 10 miles a day for 3 days before needing recharge. I beleive by using a thrust-coast-thrust-coast while maintaining an average speed kept the motor from overheating and gave me longer run time.
I want to upgrade to 48 volts to hopefully increase the speed and LiPo battery to lessen the weight. This is purely for recearation so run time is not that important. At the moment the only place to i know to look for a wheel and battery is on Ebay.
Thanks to this forum I am getting the answers to some questions I have.

 

[Mr EBIKER]

I did the same to my scooter it was 36V w 3 lead acid battery, After the bttery died I replaced it with 36v 30ah li-ion pack.
used te same "brushed" motor and top speed remained the same 28mph to 30 downhill but lost some "tourqe" I also have a 48V 30ah pack but afraid to use since my brushed controller only had 42v caps?? So I wanted to change controller but very limited with brush motors so its just sitting with the 36V. I couldnt shunt mod them. I dont know if I want to invest more money and time since it has the real bad double shock suspension, maybe cheaper to buy a used good scooter platform, upgrade the wheel to brushless motor or keep it at 36v and sell it.

 

[ElHegpah]

Try Amazon for additional shopping.

Lipo is dangerous, I refer to it as "rocket fuel in a baggy". Li-ion is much better for regular use.

 

[jimmycash245]

Hello,
2000w hub motor. it depend on how far you wanna go. using 45a Controller paired with a 52v Battery with 50BMS is just fine.
so 45A x 52v =2340w 52v x 20ah battery 1040w round about. 1040w/2340w = approximately .5 hour if you were to keep it WFO and you didn't have any thermal issue.The amps of the battery merely give you the gas if it were. As you move towards half of tank of "juice" the controller will cut watts back. a good warning to have. you also have to look at the controllers voltage threshold because your done at that point the voltage of the battery lowers as watts are used. and a note about the batteries try to keep it below 80% usage for better battery life. learning to manage your juice is kinda fun and the less watt output used the more ride time you can do.

 

[addertooth]

I will be tempted to ask how beefy are the drop-out lugs for your front wheel.
Below is a picture of front drop-out lugs designed for a 1kw motor.
At the thinnest part of the ridge/hood they are 15 mm thick (a bit over 5/8ths inch thick).

Remember, a hub motor twists against the slot the motorized hub slides into.
Some people have had traumatic failure of the slot in the front fork. Make sure
yours is beefy enough for a motor with that much torque.

The drop-outs are aluminum on the bike pictured below. Steel is a bit more "chewy" than aluminum and
less likely to fracture catastrophically for the same thickness. But you have to monitor the flats in your
steel drop-outs to make sure they are not "wallowing" from impact from the flats of the motor axle shaft.