Removed the roof in anticipation of viewing the meteor show tonight... maybe. Fog has been really consistent and really thick; although the sun broke through for a few hours later in the day yesterday.
Today the sun looks like this:

I suppose I'll ride the into town today if the fog lifts, if only to check on the Century plant's condition
(answer: condition after blooming = "dead")
--- but how fast does it decompose?
"we don't know" (we meaning "me")
amberwolf said:
The fingers said:
By reversing polarity of a DD hub and sending a low voltage through it, could it function as an electromagnetic retarder to provide braking assistance, such as when descending steeper grades?
You can do that, but I am not sure what it will do to the controller or motor.
This will waste power and create a lot of heat in both the motor and the controller, because if you don't provide a voltage to the motor higher than what will be self-generated by the motor at that speed, then current will want to flow in reverse of what you are trying to put thru it, so your electronics will actually be experiencing voltages higher than what you are applying to them. (I think)
[Rod Serling]for your consideration, if you will[/Rod Serling] accidentally install your DD motor
backward. Without using the motor you cruise down a 10% incline. as you reach the bottom you apply power to the motor.
result:
Instantly the motor locks up the wheel, but then starts skidding the tire in reverse to the dction the bicycle is traveling, which effectively reduces friction between the tire and the road surface. i.e reducing the braking force.
(don't bother asking me how I know)
amberwolf said:
...
Plug braking, or shorting out the motor phases to each other without trying to save the power off of them, just dissipating it as heat, brakes very well, too, but if you do it frequently like in traffic, *and* use that motor for acceleration right afterward, is going to take a much bigger or better-cooled motor than normal regen would (which itself still creates a fair bit of heat).
I attempted plug braking on a trailer with dual DD motors, one per wheel.
result:
Even with almost 100 pounds of sled batteries, the tires locked up
Synchronous Rectification braking might need a good spanking on, but as previously posted, I've grown too old to build electronics stuff. Nor will I bother researching the subject. Others should work on this if interested.
A good e-brake would be a [Paul Revere and the Raiders]"Good Thing"[/Paul Revere and the Raiders]
A single DD hub has to absorb 500W-5kW for 30 seconds for my application (downhill "drag braking") which is why I give credence for using two DD motors
amberwolf said:
Maybe you could get Farfle or someone else that's done a hollow-axle motor successfully to modify one for you?
(because I'm an idiot I forgot this part) Actually, since I'd have to build a stub axle anyways it might as well be 20mm in diameter [puts on thinking cap with burnt out propeller]
ddk said:
Back to the present MT- I can see replacing the NV hub with a geared hub that drives trough the sprocket of a dd that drives the axle. (cornfusing)
amberwolf said:
Yeah, that's complicated, plus I don't trust any of the DD hub's drive side threads to actually not break off under power--I think they only design them to take a cassette or freewheel so they can still call them bikes--not so you can actually pedal or otherwise apply much power thru them, because I've seen too many instances of sheared-off threads or the entire threaded section breaking off the cover (sometimes including the axle bearing!).
I did not consider this aspect.
I successfully use the freewheel threads as a drive sprocket holder-on-ner as attested by MT's current attire, which already has many thousands of miles on it. A Bafang geared-hub motor with a track sprocket threaded on the motor's freewheel threads drives the input of MT's NuVinci hub transmission (I'm nowadays fairly used to dealing with complicated drive trains and chains)
I consider using two motors, each geared for very different top speeds to be a replacement to the NuVinci, where I use single speed gearing for the pedals (since I'm no longer able to add appreciable energy to the trike's drive, why bother? )
I've discovered whilst using MT I only change the NuVinci's transmission settings going up greater-than 10% grades.
I resume my more normal 1:1 setting below a 10% grade. I rarely use the 1:5 overdrive. (mainly by accidentally twisting the worm control too far)
Gearing down a second motor (actually a third motor) to accomplish the same thing seems eminately cheaper (and more reliable) than continuing using the NV transmission. Which is known to fail when too much torque is applied to the drive-side (or, if you will, just
enough torque is applied)
I was hoping to use both one flange and the freewheel threads of a DD motor to accomplish my chaining duties.
- I do have a 20-tooth sprocket drilled for the disc brake mounting holes and shall use that instead of a track sprocket.
Because of the 20-tooth sprocket I am forced to use the 350W geared-hub motor as the "hill-killler-motor".
But I know that application works
just fine :wink: