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Help choosing a bike upgrade
- Thread starter Gecko6090
- Start date
ZeroEm
Minor legend
Trikes top speed is 33mph. Built it for 28 mph want a few mph faster so it does not need to slow down to start pulling hard. Took my time figuring out my build, still happy with it.
I suspect that 60Nm is just shy of what you need to climb the steep section of your hill. The problem is, you only have 60Nm at 0mph, and the it drops off quickly after that. You need the 60Nm at the speed you need to climb the hill. Faster is better to keep the motor in a good efficiency range, but faster means less torque. (on my bike, at half throttle, I'll climb 20% at 15mph and 75Nm at the rear wheel, but at 250lb).
You could increase the current, which could get you up the hill, but may torture the motor from running so slowly. You want to stay as far from stall as possible.
If you also up the voltage to 48V, you now have enough torque to maintain 12mph, and have 80Nm available at 8mph instead of 4mph.
Ya that sucks. I'm running a super slow 2V/sec throttle ramp to keep my bike controllable, and it still wheelies at 20mph if I hit the throttle if I run in speed 3. I only ride in speed 1 of 3 (2 in traffic), and never without the slow ramp and current limited to 70A, unless it's for testing. That's the downside of achieving higher torque between 20 to 40.QS 205 3K 6T90 phase amps strong accel.@120 phase amps will put you on your ass if your weight is not over the front wheel when you hit the throttle. The reality of phase amps and torque. Lol
stancecoke
Minor legend
Why are you mixing the amps again?!
If you want to compare something, use the same motor current and the same battery current * battery voltage for the same power. Everything else is comparing apples and oranges.
If you compare apples with apples, the higher battery voltage will change exactly nothing, you will burn your motor within 4 minutes.
@Gecko6090 wants to switch to a middrive, he doesn't want to pimp his hubmotor
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Because I'm showing that the ultimate solution for getting torque at the right speed may be to change both current and voltage. The two examples are iterative and the second achieves the goal, by adjusting both. Your solution is just to adjust amps, as in the first iteration. Trying to solve the OPs issue.Why are you mixing the amps again?!
If you want to compare something, use the same motor current and the same battery current * battery voltage for the same power. Everything else is comparing apples and oranges.
View attachment 372468
@Gecko6090 wants to switch to a middrive, he doesn't want to pimp his hubmotor
Did you notice the word "also"?
So you feel it will take more than 4 minutes to climb one block?? The fact is, there are more ways to skin a cat, and I'm providing mine based on the specific situation. You feel there is only one, and that's where our opinions differ. Are you OK with someone having a different take on things? If so, I think we're good.If you compare apples with apples, the higher voltage will change exactly nothing, you will burn your motor whitin 4 minutes.
My approach is to determine where the torque doing what is needed to obtaining it, rather than increasing maximum torque. Make changes, test, look at the results, repeat. The Grin simulator is incredibly accurate in comparison with real world testing.
stancecoke
Minor legend
Sure, but I always want the people to understand the physics behind an EBike motor. There are just very few basic formulas, that are describing the behaviour of a motor. This formulas are used in the Grin Simulator. So if you tell a newbie, that a higher battery voltage is increasing the torque, I have to disagree. Even if you are right for certain operating points.
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