Yeh I saw the watt they suck. They are not really efficiently but I am sure powerful. I also see a lot ofbfmdofference compare to different motors I have tried. Some of them can really demand 1,5 times more current. Usually it comes down to more heat production
Oh boy. I thought the my hummies are inefficient TIL.
Still owe you guys a raptor hubs review. I’ll get it done soon. Raptor vs Hummie comparison will take a little longer since I would prefer to provide Metr data for both on the same setup.
It will be the most wanted comparison of 2019. Looking forward and definetely on the same setup would be perfect.
Not sure if lid or full body standing mirror
It would be really appreciate:)!
Is the thickness the primary reason to replace? If not, you can use the steel lid with the pop rivets, and get the good fit back? You can add foam or plastic under the grip perhaps, to give more shape, if you hate the flatness.
Oh I see the lid has the threads for the hinge screws. Damn. Maybe another way to deal with it is to countersink the holes on top, get countersink screws, and add some nuts to the bottom?
If the material is steel then the easiest way it to get them welded together. Just few ponits inside at the level of the screw and threads and they will never move again.
I am not sure if it’s just because of heat production. It’s also a function of rpm and torque(assuming other factors are same). Let me see if Matlab has some simulations related to this.
that would be nice. I know that the lower the kv the higher heat production you have but in my case the lower Kv motors were the coolest.
Yeah the lid was too thick to fit my 12s5p boxes. And I really dislike the fact that it’s just a flat piece of metal. You probably can use countersink screws but I like my pop rivots better
Joined up the small group ride halfway from flywheel cafe to the ferry building, then solo back to the car following regular groupride route.
49v >>> 37v, 450Wh, 14.5miles
Do you still beleive motor temp is just bad reading ??175C is crazy !!
I’m sure it’s just bad reading. Shoot! I totally for to to bring my temp gun again. I adjusted the beta to 3900 as @Deodand mentioned. Not sure if there’s an official fix yet. The trucks definitely don’t feel that hot.
Looks like consumption improved a bit, or just riding style, even so, almost 19 Wh/km
I don’t remember if I posted this before, but you can find the correct beta yourself, measure temperature and thermistor at ambient, then get a hair dryer, or a oven if you know that it won’t get above 70~80°C and leave it for an hour or more until the temp stabilize, measure resistance and temp of the motor itself again and plug the numbers here
https://www.daycounter.com/Calculators/Steinhart-Hart-Thermistor-Calculator.phtml
Another theory I have, the beta is correct, but the motor is getting so hot that it’s out of the thermistor valid range, I think the standard method of measuring beta is doing the procedure above using 25°C and 75°C, the datasheet say what temperatures were used
Let’s say we are actually at 120°C, since the equations that relates resistance and temperature is logarithmic, the error can shoot out of he real value really quick for extremes
EDIT: what I said appears to be true, take a look here https://eecs.oregonstate.edu/education/docs/datasheets/10kThermistor.pdf
Just as an example obviously, but at 125°C for this particular thermistor we have an increasing error
I think it’s more of just style. we werent going fast at the beginning. cropped down to just the solo ride. (5:12 - end). it comes down to about 36 Wh/mile
I understand the increase inaccuracy at the extreme ends of the thermistor spec curve but still a little confused about how to measure beta. to get resistance value do I probe across the temp and 5v of sense wire?
@Blasto did some tests dunking the motors in an oil bath and heating to 150C, experiments put our beta value at 4100.
flashing it right now
450wh for 23km!!! I use 300 for 28 on my hummies.
yup. can’t wait to get my hummie build fixed.
Sounds like the replacement lid is just too thin.
Perhaps you could hurdle over the lack of concave problem and the strength problem by building up a a layer of epoxy to simulate a concave, adding rigidity in the process, maybe add a backbone into it