Wiring Schematic Help

General Discussion about large electric scooters and motorcycles and other things with no pedals.
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johntaz   1 µW

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Wiring Schematic Help

Post by johntaz » Apr 08 2021 2:20pm

After doing LOTS of reading and gathering of supplies, I'm finally ready to start off my project. Build thread coming soon(?). I'm at a point where I need to figure out wiring before moving on to mounting parts on the bike.

Plan is to take 10 Nissan Leaf modules (got for free, basically) for a 20s 72v setup. Already purchased the QS138 90h 4kw motor and SVMC 72200 controller. I have the battery pack mounted to the frame, and place carved out for the motor/controller.

Would you mind taking a look at my wiring diagram and letting me know what you think? I have some experience rewiring ICE motorcycles, but this is my first attempt at creating a diagram from scratch. Feel free to rip it apart.
Kawasak-e wiring.JPG
Kawasak-e wiring.JPG (62.44 KiB) Viewed 168 times
KZ440 - 72v Conversion
QS138 90h 4kw motor
SVMC 72200 controller
Goal: Top Speed 75mhp, 40 mile range

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JimVonBaden   100 W

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Re: Wiring Schematic Help

Post by JimVonBaden » Apr 09 2021 10:41pm

Might be a bit simplistic. I do not see a contactor there.
From my Vespa conversion. 72V, 38ah battery, Kelly KLS...N controller, 4KW hub motor.

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johntaz   1 µW

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Re: Wiring Schematic Help

Post by johntaz » Apr 10 2021 1:11am

Thanks for your diagrams, Jim. I agree, it's simplistic, but it's more meant to be just the powertrain and major components, similar to your first diagram. The 12v wiring is more within my comfort zone, so I haven't bothered with that diagram, yet. I like the way you separated out your diagrams. I might borrow that idea from you. At this stage, I just want to get the bike moving under it's own power, SAFELY, first.

I did put in a main contactor. It's right in the middle on the diagram. My attempt is to power the system with the key switch, have that turn on the resistor relay and trip a programmable digital timer {~5 seconds), and then have the contactor close with no additional input from me. Can anyone weigh in on this and let me know if they think this would work?

I also want to wire up the dc/dc after the bms, so it doesn't draw power when the bms is off. The and bms I have turns off and on with a momentary switch - am going to try to wire that up to the the "reverse" button on my handlebar controls.

Any other feedback on the way I have this? Is it workable and safe? Or am I going to blow my garage up? Anything that you can suggest to tweak?
KZ440 - 72v Conversion
QS138 90h 4kw motor
SVMC 72200 controller
Goal: Top Speed 75mhp, 40 mile range

Elektrosherpa   10 W

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Re: Wiring Schematic Help

Post by Elektrosherpa » Apr 10 2021 5:51am

Interesting to see those wiring diagrams.

One question:
For what purpose did you both put a "key switch" AND a "kill switch" ?
Wouldnt it be sufficient to have just the key switch?

And as for the key switch:
I am planning to use one from the 230V-shelf.
Dont you think this is a safer solution than using 12V- switches?

AussieRider   100 W

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Re: Wiring Schematic Help

Post by AussieRider » Apr 10 2021 7:42am

Hi people's.
Johnatz, you schematic is an impressive first effort. I look forward to your build thread.
Jim, your vespa build speaks for itself. You sir, are a genius & an artist.
Elektrosherpa, your Bultaco conversion is a gem. You, as a dirt biker, should know how important an easy to reach kill switch say, on the handlebars is
rather than just the key switch under the seat / beside the steering crown or other hard to reach place in a fall bike manufacturers choose.

AussieRider
Evolving E-bike
Retro style mid drive beach cruiser
Mid drive chopper
EVT 168 scooter

johntaz   1 µW

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Re: Wiring Schematic Help

Post by johntaz » Apr 10 2021 9:06pm

Elektrosherpa wrote:
Apr 10 2021 5:51am

And as for the key switch:
I am planning to use one from the 230V-shelf.
Dont you think this is a safer solution than using 12V- switches?
I'm far from an expert, but I assume 230v switch your talking about is AC, not sure what it's rated at for DC, if it is at all. If it's only switched on/off with no load, that might work. If you ONLY have the key switch, and no kill switch, you run the risk of not being able to cut the power under load in an emergency (arc). Also, I know some people have had issues with contacts welding closed when using AC switches on"high" voltage DC, even under normal use. This is the main reason, best I can tell, for using a 12v system with relays to handle the high voltage DC. That and the size/price/availability of 12v components.
KZ440 - 72v Conversion
QS138 90h 4kw motor
SVMC 72200 controller
Goal: Top Speed 75mhp, 40 mile range

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JimVonBaden   100 W

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Re: Wiring Schematic Help

Post by JimVonBaden » Apr 10 2021 11:42pm

johntaz wrote:
Apr 10 2021 1:11am
Thanks for your diagrams, Jim. I agree, it's simplistic, but it's more meant to be just the powertrain and major components, similar to your first diagram. The 12v wiring is more within my comfort zone, so I haven't bothered with that diagram, yet. I like the way you separated out your diagrams. I might borrow that idea from you. At this stage, I just want to get the bike moving under it's own power, SAFELY, first.

I did put in a main contactor. It's right in the middle on the diagram. My attempt is to power the system with the key switch, have that turn on the resistor relay and trip a programmable digital timer {~5 seconds), and then have the contactor close with no additional input from me. Can anyone weigh in on this and let me know if they think this would work?

I also want to wire up the dc/dc after the bms, so it doesn't draw power when the bms is off. The and bms I have turns off and on with a momentary switch - am going to try to wire that up to the the "reverse" button on my handlebar controls.

Any other feedback on the way I have this? Is it workable and safe? Or am I going to blow my garage up? Anything that you can suggest to tweak?
Oops, missed that. Looks good.

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JimVonBaden   100 W

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Re: Wiring Schematic Help

Post by JimVonBaden » Apr 10 2021 11:45pm

Elektrosherpa wrote:
Apr 10 2021 5:51am
Interesting to see those wiring diagrams.

One question:
For what purpose did you both put a "key switch" AND a "kill switch" ?
Wouldnt it be sufficient to have just the key switch?

And as for the key switch:
I am planning to use one from the 230V-shelf.
Dont you think this is a safer solution than using 12V- switches?
I use two so I can turn on the 12V without turning on the contactor.

As for the use of 12V switches, the voltage is unimportant. It is the current that counts. I have about 1/3 of an amp on both switches. My fuse is 2 amps. Not an issue at all.

AussieRider   100 W

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Re: Wiring Schematic Help

Post by AussieRider » Apr 11 2021 7:23am

Hi people's
A few years ago, on another forum, I remember a motorbike build that used a large circuit breaker in the main battery lead that was connected via a cable to the redundant clutch lever as an emergency shutoff.
Would that work for yours?

AussieRider
Evolving E-bike
Retro style mid drive beach cruiser
Mid drive chopper
EVT 168 scooter

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