Elegant solution for 72v main power switch

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81style   10 mW

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Elegant solution for 72v main power switch

Post by 81style » Oct 30 2018 5:30pm

Friends
Can anyone suggest an good solution for a main power switch for my 72v build? I was thinking of adding a DC circuit breaker between the battery and controller, but perhaps there is a more elegant solution? The really slick options such as solid state push button switches seem to be for 52v and lower builds.

Any thoughts?

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skeetab5780   10 MW

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Re: Elegant solution for 72v main power switch

Post by skeetab5780 » Oct 30 2018 6:32pm

Could use a fancy contactor with magnetic blowout, they are cheaper from China
https://www.google.com/amp/s/www.electr ... et%3famp=1

E-HP   1 mW

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Re: Elegant solution for 72v main power switch

Post by E-HP » Nov 06 2018 4:54pm

I used one of these, but I wouldn't call it elegant. It will appear more elegant when I fabricate an aluminum channel frame around the bike's triangle, that I'll cutout to fit the breaker, but for now it's better than unplugging the battery when not in use:

https://www.amazon.com/gp/product/B000W ... UTF8&psc=1

John in CR   100 GW

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Re: Elegant solution for 72v main power switch

Post by John in CR » Nov 06 2018 8:58pm

If your motor is a 3 phase brushless, then there should be no need for a main power switch. Instead put a simple, cheap, reliable key switch on the low power input to the controller's logic section of the controller. Even my 20-30kw builds don't have or need main power switches. Safety features include an appropriate fuse at the battery, a key switch to cut power if all else fails, and ebrake switches to easily and intuitively cut off a runaway condition without letting go of the handlebar with one hand.

Elimination of unnecessary components is always the most elegant solution to me.

81style   10 mW

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Re: Elegant solution for 72v main power switch

Post by 81style » Nov 09 2018 12:30pm

John in CR wrote:
Nov 06 2018 8:58pm
Elimination of unnecessary components is always the most elegant solution to me.
I definitely see the appeal of this approach.
John in CR wrote:
Nov 06 2018 8:58pm
Even my 20-30kw builds don't have or need main power switches
20-30kw? Wow, that's serious power! What voltages are these builds operating at? I'm using a Phaserunner on my 72v build and the remote on/off for that controller is at battery voltage (but with very low amperage), so one of my challenges is finding a switch to use here that will not be subject to arcing. Would you mind elaborating on what you use to switch your controller either here or in this thread: Remote On/Off Switch for Phaserunner V2

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Chalo   100 GW

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Re: Elegant solution for 72v main power switch

Post by Chalo » Nov 09 2018 12:39pm

John in CR wrote:
Nov 06 2018 8:58pm
If your motor is a 3 phase brushless, then there should be no need for a main power switch. Instead put a simple, cheap, reliable key switch on the low power input to the controller's logic section of the controller.
Are there no possible fail-on modes for brushless controllers?
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kdog   1 kW

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Re: Elegant solution for 72v main power switch

Post by kdog » Nov 12 2018 7:01am

Throttle failure (mech or elec)resulting in WOT springs to mind. Don't know of any others in brushless. Had a few hair raising brushed controller failures on my mtn board. Crazyscarry!

Dumsterdave   100 W

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Re: Elegant solution for 72v main power switch

Post by Dumsterdave » Nov 12 2018 8:21am

I'm using one of these with my phaseruner at 72v and it had been working fine for about 6 months. I'm a bike courier that had to turn my bike on and off about 30 times a day and haven't noticed any arcing.

Onever Universal Motorcycle Handlebar Flameout Switch ON OFF Button For Moto Motor ATV Bike
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81style   10 mW

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Re: Elegant solution for 72v main power switch

Post by 81style » Nov 13 2018 12:05pm

Dumsterdave wrote:
Nov 12 2018 8:21am
I'm using one of these with my phaseruner at 72v and it had been working fine for about 6 months.
What happened after 6 months?

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Re: Elegant solution for 72v main power switch

Post by Dumsterdave » Nov 13 2018 1:31pm

81style wrote:
Nov 13 2018 12:05pm
Dumsterdave wrote:
Nov 12 2018 8:21am
I'm using one of these with my phaseruner at 72v and it had been working fine for about 6 months.
What happened after 6 months?
Nothing, it's still working

81style   10 mW

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Re: Elegant solution for 72v main power switch

Post by 81style » Nov 13 2018 1:38pm

Dumsterdave wrote:
Nov 13 2018 1:31pm
81style wrote:
Nov 13 2018 12:05pm
Dumsterdave wrote:
Nov 12 2018 8:21am
I'm using one of these with my phaseruner at 72v and it had been working fine for about 6 months.
What happened after 6 months?
Nothing, it's still working
Gotcha. The "had been" threw me.

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TommyCat   10 W

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Re: Elegant solution for 72v main power switch

Post by TommyCat » Nov 13 2018 3:45pm

Dumsterdave wrote:
Nov 12 2018 8:21am
I'm using one of these with my phaseruner at 72v and it had been working fine for about 6 months. I'm a bike courier that had to turn my bike on and off about 30 times a day and haven't noticed any arcing.
Please clarify, is this on the battery supply line? :shock: Or just in the controller ignition circuit?
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flat tire   10 kW

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Re: Elegant solution for 72v main power switch

Post by flat tire » Nov 13 2018 4:46pm

No switch needed. Just plug and unplug the battery. Works well with Anderson SB50, easy to clean the contacts too.

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Re: Elegant solution for 72v main power switch

Post by Dumsterdave » Nov 14 2018 12:04am

TommyCat wrote:
Nov 13 2018 3:45pm
Dumsterdave wrote:
Nov 12 2018 8:21am
I'm using one of these with my phaseruner at 72v and it had been working fine for about 6 months. I'm a bike courier that had to turn my bike on and off about 30 times a day and haven't noticed any arcing.
Please clarify, is this on the battery supply line? :shock: Or just in the controller ignition circuit?
It's connected to the 2 pin jst connector coming out of the controller

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