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now send me your 21700 stl or fusion model or step file or h00kers n’ bl0w!
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not sure which is the right side of that deal to take. but… here you go:
battery-models.12x21700.stl (1.5 MB)
battery-models.12x18650.stl (1.3 MB)
battery-models.12x20700.stl (1.5 MB)
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grasias amigo you just saved me 10 mins of Fusion…
GAWD bless you!
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note they are all 18.35, 20.35, and 21.35 mm as 0.35 was the variance in he spec sheet for one type of battery. I think it was the 20700b.
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So I’m still trying to decide battery config on both boards, so I can order and start this first board build.
On the second board 12s6p sanyo 20700b may be doable. I would be doing the stagger stack idea.
The same sanyo20700b in the tayto big ben however would be a boring simple fit, with no testing of the stagger stack workflow and it would be 45amps @12s of power.
I’m not sure what power target for this tayto. 45amps @12s might be enough. I don’t have a good reference there other than I’m heavy and more is better and my only reference is on pneumatics where I know 58amps a@ 12s ( 70amps at 10s) is just sort of enough for the hills. but lower top speeds and eurothane suggest that that’s perhaps plenty.
However 20700s in the tayto fit perfect 9 across and it doesn’t test stagger stack. so i could go with 12s3p of 30Tor 40T … and I would get more amps. which again i don’t know if I really need.
thoughts?
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Trying to work out the KV on these hummie hubs. so I have them on the bench hooked up. to the ESCape using a 10s battery from my other board. controlled via vesc tool.
I’ve assumed they are 7 pole pair.
tried using the kv command. I don’t understand it. i got it to spit out values from 470 - 512 v/rpm assuming divide by 7 pole pairs that’s 67 - 73 kv
trying alternate route. capturing a moment of realtime data. but shutting RT data off so the instaneous value stays on the screen. and doing some math
Volts = Power/I Batt
Effective Volts = Volts * Duty Cycle
RPM = ERPM / Motor Pole pairs.
KV = RPM/Effective Volts
KV = ERPM/Motor Pole Pairs / Power / Duty Cycle * I Batt
I think that’s right. ( and it’s curious that if you use motor current instead of battery current and duty cycle you get distinctly different results. )
motor 1
70.88 kv =19432/7/55.3/.949*1.34
motor 2.
59.85kv =2891/7/16.1/0.18*0.42
so some things seem not right. maybe I need to measure KV only at max duty cycle.
I was having troubles with my bench setup. strange things happening.
I think maybe my jury rigged phase wire connection was no good. the hummies have 5.5mm connectors and my ESCape has 3.5mm connectors. I’ve ordered some connectors to do something more proper going forward.
gonna wait for that and try more iterations to get something reproducible.
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How is the kv command in vesc tool terminal supposed to actually work anyhow?
it seemed to require the motor to be running and I think it needed realtime data flowing and enabled. but it gave somewhat strange inconsistent results. at first just returning zero. towards the end constantly returning the exact 512.48. number with RT data off or on, no matter the speed or the motor. like it was stuck or something.
are there docs or a forum post somewhere I haven’t found?
I’m leaning towards using the dual ESCapes for this build.
My logic is the hw60 has the three shunts and is better at dealing without sensors and the hummie hubs have no sensors.
normally I think of hw60 as one to be saved for higher current applications. but I think unity can do as well there ?
I think the Unity is HW4 based, but I’m just going off memory of Potter talking shit about HW6 having no reason to upgrade to. Quick search says Unity has only 2 shunts.
IMHO, for low KV motors, especially if you want to use HFI, HW6 is worth it.
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From all my readings all that stuck was focbox and focbox unity are hw4 based. so two current shunts. but with something better than usual on the fets that makes them handle more current. and of course with unity only using one cpu it’s even more unique.
I believe focbox unity handles high current pretty well. despite not being hw6. which was the thing i thought was better about hw6 stuff. but I also think i’ve learned the three shunts in hw6 makes it track phases better and perform better in general and better without sensors.
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Maybe because the rotor is heavy or bearings filled w grease. Maybe run them a while then try to find the kv
Right so there is something like that going on. One motor seems to have a lot more resistance than the other. I’m not sure how I should think about this.
using vesc-tool to control, a constant 3 amps spins one motor up to 95% duty cycle right away. the other would get seemingly stuck at 26% duty cycle. but letting it run for a few minutes it slowly crept up eventually seeming to break loose and jump to 95% duty cycle.
suspect motor after a minute or two of 3amp
good motor up to speed/full duty cycle at 3amps in under 3s
rerun suspect motor after that minute or two “warmed up” also up to speed in under 3s.
let suspect motor cool down for 30s or so, then it takes 6 seconds to spin up.
what do you make of this @hummieee ?
How do they spin unpowered in ur hand? I’m assuming the one w resistance is noticeable resistance in ur hand too. Be good to get the kv of each but assuming it’s not an electrical issue, which it probably isn’t, it’s gotta be compressed bearings, or some heavier grease in that one(I mixed and tried different bearings and the high heat resistant have thick grease), or possibly damaged bearing (how do they sound), or slight rubbing inside. With all these possibilities it’d be best if u ran them for at least 10 miles to eliminate any rubbing inside and we could go from there. Worst case send them brack and I’ll replace the bearings.
I can feel slightly more resistance in the one motor.
Do ten miles and if it’s still there I’ll take them n replace the bearings. But then again it could be the thicker grease and that will take more time. Do 20!
How do they sound? Could be noise from the bearing or rubbing of excess glue and that will wear down in a bit
Whatever it is do at least 20 miles and then let’s see what happens.
ok. right now it’s just on the bench running off another boards battery. was trying to figure out the KVs before deciding on my pack.
getting you a video of both now.
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left:
right:
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Hard to tell from the sound but if one is turning slowly in ur hand it’s either thick grease, compressed bearing, or glue rubbing. Can u ride them at least 20 miles and then feel again and we can decide then. Hopefully u live in USA and it’s just 18$ shipping box to me you’d have to pay. These are unused right?
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