Here is a Zappy Classic electric scooter wiring diagram showing how to replace the original PC board with a standard 12 Volt 30/40 Amp automotive relay. The original PC board was designed so the motor would not start until the scooter was pushed off to around walking speed. When replacing the original PC board with a relay the scooter should be pushed off to around walking speed before the throttle is engaged. If the scooter is not pushed to walking speed before it is started the motor and relay will have a very high Amp load placed on them which could cause these parts to fail prematurely.
The terminal numbers on automotive relays are clearly marked on their bottom side. Either a four terminal SPST (single pole single throw) or five terminal SPDT (single pole double throw) automotive relay could be used. If using a five terminal SPDT relay the middle terminal marked 87a should not be connected to any wires.
Four-Terminal Automotive Relay
12 Volt automotive relays are available on our Relays Page and they are also available at all auto parts stores. If you need a new throttle the original yellow finger-pull On-Off throttles are discontinued and no longer available however we sell an upgrade On-Off twist throttle on the Zappy Classic Parts Page.
This PC board to automotive relay conversion will also work on Zappy SX electric bicycles and electric bicycle conversion kits.
I just read the Zappy Classic owners manual and discovered that it has an on/off switch and a circuit breaker which I was previously unaware of. I am not sure if the on/off power switch is used to switch the high current power on and off between the battery and controller, or if it is a low current switch used to deactivate the throttle from engaging.
If you could attach some photos of the wiring showing the back of the on/off switch and the circuit breaker along with how they are wired to all of the other parts of the scooter then we will revise the wiring diagram to include these parts.
Thanks for attaching those photos. Thanks to those photos I was able to determine how the power switch is wired into the scooter and have updated the wiring diagram above so it is now accurate.