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Mx500 upgrade to 48v 1000w motor wiring

Hi, I am wiring 4, 12v 5amp hour to my mx500. I'm basically guting it out and replacing it with a 1000w motor. For the wiring, can I use the same connectors from the old bike, or do I buy all new ones? Also, since I'm getting new batteries, motor, throttle, controller, etc. will you give me a recommendation for the most reliable, fast set up? I'd really appericate it.Thanks.

A 48 Volt 5Ah battery pack made with four 12 Volt 5Ah batteries will have a maximum discharge current rating of 10 Amps for 30 minutes, or 15 Amps for 7 minutes. A 48 Volt 1000 Watt motor will draw 21 Amps at full power and 10.5 Amps at half power, so a 48 Volt 5Ah battery pack is not really compatible with a 48 Volt 1000 Watt motor. We recommend to use a minimum battery size of 10Ah with a 48 Volt 1000 Watt motor. I know this probably throws a wrench in your current plans however I would not want you to modify the bike and then it does not have the full amount of power that it could or the batteries get damaged from being overloaded.


The Razor MX500 dirt bike's original battery to controller wiring is 14 gauge which is a little small for a 48 Volt 1000 Watt motor. Rewiring with 12 gauge wire would be sufficient for a 48 Volt 1000 watt motor. The bike could also be rewired with 10 gauge wire if you want to upgrade to an even thicker wire. When installing new wiring, new connectors should be used because old connector terminals do not take well to having new wires installed onto them.


For the highest reliability I recommend to solder the wires onto the new connector terminals, this will insure that they will not come loose and cause a reliability issue. For our battery pack wiring harness terminals we first crimp the wires onto the connector terminals with a professional quality crimp tool (item # CRM-85) and then apply solder over the crimp area making sure that it flows into the copper wire ends and secures it. For even higher reliability, general or all purpose hot glue can be applied to the back side of the connectors between the wire insulation and inside of the connector.



Please let us know if you have any questions.

So what part recommendations do you have now. New everything, motor, batteries, etc.

To upgrade to a 48 Volt motor would require replacing every electrical component on the bike except for the charger port and power switch.

One thing that you might want to consider is using a 36 Volt 1000 Watt motor instead of a 48 Volt 1000 Watt motor. The Watts rating alone determines the power that the motor has so a 36 Volt 1000 Watt motor has the exact same amount of power and torque that a 48 Volt 1000 Watt motor has. This way by using a 36 Volt 1000 Watt motor the original size batteries can be used and there will already be a place to mount the batteries without needing to make modifications to the frame. We sell 12 Volt 15Ah batteries which are the exact same dimensions as the original 12 Volt 12Ah batteries that provide 20 percent more capacity if you want to increase the battery pack capacity. The original battery charger can also be used with a 36 Volt system which will help keep the cost of the modification parts down.

With a 36 Volt 1000 Watt motor only the motor, controller, and battery pack wiring harness would need to be replaced. The original throttle could be used with a 36 Volt 1000 Watt controller however depending on the MX500 version its battery indicator lights would either work or not with it. Battery indicator lights on earlier version 4-wire throttles would work with the new controller, while the lights on later version 5-wire throttles would not. If the existing throttle is a 5-wire one then a different throttle could be installed though in order to have battery indicator lights.

 Please let us know if you have any questions.


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