Pre-charge resistor

[vptech]

Is it suggested to use a pre-charge resistor for a stock MP III setup on 48v?

[MAGICPIE3FOCUSPOWER]

For sparking at power connectors due the voltage difference I recommended you to use a pre charge resistor.

Just use 150 Ohm 10W resistor.

[Bikemad]

A 10W resistor seems a bit over the top, I used a 330 Ohm 1/4 watt resistor and a momentary push button switch wired directly across the main switch contacts.
Simply hold the button down for a second before throwing the switch and you'll get no arcing across the switch contacts whatsoever.

The only downside to this is if someone decides to hold the button down and simultaneously operate the throttle, in which case the resistor will then overheat very quickly.

Alan
 

[MAGICPIE3FOCUSPOWER]

Nope 10W is not overkill, I am using this with just normal connectors.

Also as you said it can be hot, so 10W........

[Morgen 3Eman]

This another great application for a light bulb.  It even indicates when the charge is complete!

TTFN,
Dennis

[MAGICPIE3FOCUSPOWER]

What do you mean?

Just use two connectors for the pre-charge resistor.
Just use two connectors for main power.

Just connect the main power connectors first than pre charge connectors.
And 150 Ohm is just enough to load the controller in a short of time.

I have used 1K resistor it took a long time to load the controller.
So when connected the main power connectors they still sparked.