the kickstarter mentions a your choice option from 60 - 85 kv. so I wouldn’t expect you to know anyone’s off the top of your head?
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by my calcs ( I use 82% of theoretical max):
10s 60kv = 20mph @4.2v/cell -> 16mph @ 3.4v/cell
10s 85kv = 28mph @4.2v/cell -> 23mph @3.4v/cell
12s 60kv = 24mph @4.2v/cell -> 20mph @ 3.4v/cell
12s 85kv = 34mph @4.2v/cell -> 27mph @3.4v/cell
so that range suggests to me knowing the KV is important to be able to choose the battery config.
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Based on that I would say just go with 12s…boards usually go slower than the theoretical speeds and 27 max speed isn’t that high. Plus you’ll get better heat dissipation with less amps, its not like the ESCs you listed will cry at 12s
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those numbers are already 82% of theoretical max.
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If ur doing 82% of the no load speed when under a load I think that’s pretty good. I forget what percent I was doing but the higher the better.
10s and 25mph sounds right. @BigBen
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If you message the DALY store on AliExpress they have 12s li-ion up to 80A discharge I think
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Nice build!
Yep! Mine is gonna look similar.
10s3p VTC5A
Makerx Dual v4
Tayto + @BigBen enclosure
Loaded Hubs
VX1 Remote
Can’t wait to finish it and try it once the lookdown finish here in Spain.
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anyone know the dimensions on @dickyho esc?
any reason to not use it vs the d140? he really gave excellent customer service on an issue I had with some pulleys so I’d like to repeat biz there.
where do people buy d140s from?
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more fake batteries ( 20700 ) and a fake D140
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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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