Ebike fuses.

[Philcordero]

I have a 48 volt 450 watt bike and I am trying to replace controller with a 1000 watt 48 volt controller. I have a 10000mw 48 volt battery. When I connected controller only (no motor, accessories) it will blow a 20 amp blade fuse. (20 amp 12 volt). Do I need to get a 48 volt slo blow fuse like in golf carts? I bought two controllers and they each blow fuses. I can not find any mention of fuse values. Thanks!

 

[maddox]

In all the packs I opened , there is a 30A blade fuse , like in cars.

When does the fuse blows, when connecting? Or when throttling up?

 

[Philcordero]

It blows when I first turn it on with only the power leads connected. From the battery wiring goes thru a blade fuse to a toggle switch then to controller. When turned on there is a surge then it blows. I had been using a 20 amp fuse which I see is wrong. If watts equals amps x volts. A 1000 watt controller at 48 volts should equal a little over 20 amps. But this does not account for a start up surge. Also most fuses I see are for 12 volt. I am looking at a 48 volt slo blow in the range of 25 watts.

 

[maddox]

Several options, but the least "annoying" one is that the capacitators of the controller ask to much of the poor fuse.

You could try with a "spark surpressor connector", that precharges the caps with restricted (resistance) power.

Also, a 12V fuse will do 48V, volts don't blow fuses, amps do.

 

[Philcordero]

First off I thank you for your time and expertise. I will look into the spark suppressor. L faster (mid motor supplier) replied they use a 25 amp and a 20 amp fuse (I guess the 20 amp is in the battery charge circuit). I think using a slo blow fuse would help. I have a wire feed welder with 30 volt power yet the amps are enough to weld so I see "volts don't blow fuses. I will also check golf cart 48 volt fuses. Thank you again.

 

[maddox]

Slow blow fuses can help. The amount of time the cap's draw boatloads of amps is very short.