Power in Flux

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Spaceweasel created the thread California bans ICE cars and trucks by 2035 - but not bikes.
" Gov. Newsom just signed an executive order banning the sale of new ICE cars and light trucks after 2035.
https://www.gov.ca.gov/wp-content/up...79-20-text.pdf

Conspicuously absent from this is mention of electric motorcycles. Given the rapid advancement of battery tech I expect ev bikes will be plenty competitive on range/weight/power by then. I'm sort of surprised he didn't include them. "

1 Hour Ago

Stevo clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by Spoonman

7 Hours Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
" Acceleration under gravity is certainly a constant.
Accordingly, velocity builds linearly to the point of aerodynamic significance.
Displacement is a second order function alright, but not either of the others.

With the bike, if we can assume full current from 0 RPM then, winding effects neglected, the torque will be a constant up to the point where the BEMF comes into play.
Consequently the acceleration must also be constant, and hence the velocity gain linear (to the point of aerodynamic significance).

To your arse it won't feel like that though. "

9 Hours Ago

Stevo replied to the thread Adding a centrifugal clutch to the drag bike..
" Attachment 8509


Is Acceleration exponential at the start?
When you drop an object from a tall building, it takes an acceleration constant to reach max velocity, then the speed varies by wind drag, but the initial acceleration from a dead stop isn't linear. If you dropped a heavy Pb ball and a really light ball same size, they should still fall at the same velocity. But that is gravity, not emf.
Maybe your feeling that initial exponential acceleration in the seat of your pants! "

11 Hours Ago

Stevo replied to the thread Stacking chargers (Just in case you wanted to know.).
" Are you going to add your own reverse protection? I used a solar panel diode between my 2 Mean Wells. I had one on both power supply's + outputs and probably not necessary as these MeanWells have reverse protection built into them. One of the diodes fried on the + to battery pack output after months of charges. They are rated for 50 amp. I havent had any more issues for months of charging now.
I was wondering how others are charging their packs. Thanks for sharing. "

11 Hours Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
" oh my goodness that's pretty! "

13 Hours Ago

EVcycle replied to the thread Adding a centrifugal clutch to the drag bike..
"
Quote Originally Posted by Spoonman View Post
When you say AC you're referring to PMAC not squirrel cage I expect yes?
Yes, A Motenergy 1507. "

17 Hours Ago

Spoonman clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by EVcycle

19 Hours Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
" When you say AC you're referring to PMAC not squirrel cage I expect yes?

You've answered my question in any case - it sounds like there's a necessary lag until sufficient angular velocity is developed to really launch the thing (which makes perfect sense of course), so having something in there which permits you to have it spun up before you try and move certainly makes sense alright. "

19 Hours Ago

EVcycle replied to the thread Adding a centrifugal clutch to the drag bike..
"
Quote Originally Posted by Spoonman View Post
How sure are you that this isn't more to do with how your controller is programmed than anything else?
If you're dealing with some sort of software limit on the ramping rate for current, then the flywheel dump may not help as much as you expect as the controller is still going to attempt to regulate the rate of change - granted if any such rate is RPM linked then it may not try quite so hard... but the point is that there are a substantial number of unknowns there.

Once the magnetic fields are established (for which I would expect there will be a larger time constant in the case of induction than PM), then the torque should be pretty much instant in any practical terms. Only reason for this not to be the case is if something is the control stages is trying to be too clever.
AC motors.....100% torque at zero RPM is still not moving HP. This is not always a bad thing as in Drag racing you do not want to "blow your tires off"

I have everything running at 100% in the controller (2 different controllers and motors) The start seems soft until I get to about 100 RPM or so.

I recently had an interesting chat with one of the leading AC motor manufacturers explaining my 100 RPM theory and was surprised to find out that the was the magic number to get things really rolling...100 RPM. The had proven it on a dyno.. (go figure)
Depending on your gearing, you may get to 100 RPM very quickly so it may not be noticed, but I have two vehicles with no transmission and am drag racing them to 100+ MPH in a 1/4 mile.

I still think a centrifugal clutch would help us with our ET.

Ed "

1 Day Ago

EVcycle clicked Likes for this post: Adding a centrifugal clutch to the drag bike. by Frank

1 Day Ago

EVcycle created the thread Stacking chargers (Just in case you wanted to know.).
" Yes Dorthy you can mix and match chargers if you do it right (This may have been discussed already), Here is my setup.

In the photo you will see 3 chargers Juicing up our Legend dragcar. I use a similar, but different, setup on my Drag bike (more on that later)

Attachment 8508

There are three chargers, one 100.8V 8A charger. It is a smart charger, but with no reverse protection. I know it this as I had a millisecond short and the second 100.8 V 8A one that was on the board toasted itself even with proper fusing.

The other two (stacked) ones are 50.4 4A really smart chargers I got cheap while I wait on some more 8A ones to arrive from China.

They are charging the same battery pack. (6P2S 100V 1350A) Chevy Volt packs

The two smaller chargers are in series to give me 100.8 at 4A and are connected via a 10 foot cord to the front of the battery pack.

The 8A charger is on a 15 foot cord and connected at the other end of the pack. There is enough resistance in the cords and batteries that the changers do not fight each
thinking there is a full charge until there really is one.

On the dragbike I have a 50.4V 12A and a 67.2v 12A charger (2 Chevy Volt Packs) The packs are split with a contactor in between them so that each battery has it own charger.

It all works great. Recharge times at the track are from 20 to 45 minutes depending on if we are at a 1/8 or 1/4 mile event.

Enjoy!

Ed "

1 Day Ago

Richard230 clicked Likes for this post: The Long Way Up by ElMotoMike

2 Days Ago

Spoonman replied to the thread 1970 Honda CT90 Electric Conversion.
" To be fair, at least you'll be paying for the best solution and not a hack job.

Nice project. "

2 Days Ago

Spoonman replied to the thread 1979 XS750 electric conversion.
" Yeesh - that's a good sized gap there alright.
Are those studs integrated?

I don't see that arm squeezing down enough to make the studs work. If you could change them out then you could use heavy spacers to take up the gap - it wouldn't be pretty bit I expect it would serve well enough and I expect you'll need to do something to that effect in any case to maintain cable clearance.

To do it right though you're looking a refabrication IMO. Retain the pivot and have some new box section with the right dimensions welded up with some appropriate relief for the cables. "

2 Days Ago

Spoonman replied to the thread Adding a centrifugal clutch to the drag bike..
"
Quote Originally Posted by EVcycle View Post
the Toque at Zero RPM is not really translating to the wheels when the motor is stationary in a AC system.
How sure are you that this isn't more to do with how your controller is programmed than anything else?
If you're dealing with some sort of software limit on the ramping rate for current, then the flywheel dump may not help as much as you expect as the controller is still going to attempt to regulate the rate of change - granted if any such rate is RPM linked then it may not try quite so hard... but the point is that there are a substantial number of unknowns there.

Once the magnetic fields are established (for which I would expect there will be a larger time constant in the case of induction than PM), then the torque should be pretty much instant in any practical terms. Only reason for this not to be the case is if something is the control stages is trying to be too clever. "

2 Days Ago

ElMotoMike replied to the thread The Long Way Up.
" Started watching today. Those generators are coming in handy. "

3 Days Ago

Frank replied to the thread Adding a centrifugal clutch to the drag bike..
" Before upgrading to a larger controller on my drag bike a few years ago, one of the options I looked at was using a snowmobile clutch. You could keep a motor close to Max power with some sort of cvt.

Sent from my SM-T380 using Tapatalk "

3 Days Ago

biothundernxt replied to the thread 1979 XS750 electric conversion.
" I sized up the motor with the swingarm I got off the Fazer, but it looks like I will have to do some modifications... Any suggestions?Attachment 8503
Attachment 8504
Attachment 8507
Attachment 8505
Attachment 8506 "

4 Days Ago

biothundernxt replied to the thread 1979 XS750 electric conversion.
" This week, I built a temporary stand for the motor out of wood, and hooked up the controller and a small 48v battery I built for another project to test everything:
https://youtu.be/zs7Qzl2n8bo "

4 Days Ago