Choosing Ground

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n1866878   100 mW

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Choosing Ground

Post by n1866878 » Aug 13 2018 9:37pm

Hey,

We're building an electric go-kart with a 48V main battery and 18V secondary battery. We have an old go-kart chassis with a metal core structure. I'm just wondering - is there a need to connect the negative terminals of the batteries to the chassis metal frame?

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teklektik   10 GW

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Re: Choosing Ground

Post by teklektik » Aug 13 2018 9:53pm

Don't do it.
Hot chassis NG...
Visit Grin Technologies at www.ebikes.ca
Build Thread: 2WD Yuba Mundo V4

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Hwy89   1 kW

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Re: Choosing Ground

Post by Hwy89 » Aug 13 2018 11:29pm

Run all ground wires back to the negative terminal of the battery. What does the secondary battery do?

n1866878   100 mW

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Re: Choosing Ground

Post by n1866878 » Aug 14 2018 10:45am

Hwy89 wrote:
Aug 13 2018 11:29pm
Run all ground wires back to the negative terminal of the battery. What does the secondary battery do?
Secondary battery is for powering the controller at 18V and also for switching the coils on the main contactor on/off.
Right so - I'll keep the two batteries in their own loops then without touching the chassis frame.

What's the reason behind not connecting negative terminals to the chassis frame? I mean GND is GND right, why is it dangerous?

Jon NCal   1 kW

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Re: Choosing Ground

Post by Jon NCal » Aug 14 2018 11:58am

One, there is no reason for it. Two, increases the possibility of an accidental short circuit.

Voltron   10 MW

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Re: Choosing Ground

Post by Voltron » Aug 14 2018 12:12pm

Especially with the higher voltages of normal bike batteries compared to car 12v.

n1866878   100 mW

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Re: Choosing Ground

Post by n1866878 » Aug 14 2018 3:33pm

Perfect. Thank you all.

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