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Discussions Question and Answer Forums Electric Scooter, Bike, and Go Kart Repair Forum

Sunl 500W electric scooter fuse.

Does anybody know what size fuse my Sunl 500W scooter would take??? I don't have an owners manual and the fuse in it, has no markings on it.

On most electric scooter makes and models 24 Volt 500 Watt scooters use a 40 Amp fuse, 36 Volt 500 Watt scooters use a 30 Amp fuse, and 48 Volt 500 Watt scooters use a 20 Amp fuse.

For 250 Watt scooters the Amp ratings quoted above should be divided by 2. Here is a chart showing what fuse ratings most electric scooters, bikes, and go karts use.

24V 250W = 20A
36V 250W = 15A
48V 250W = 10A

24V 500W = 40A
36V 500W = 30A
48V 500W = 20A

24V 750W = 60A
36V 750W = 45A
48V 750W = 30A


24V 1000W = 80A
36V 1000W = 60A
48V 1000W = 40A

All fuse manufacturers stamp the Amp rating of their fuses on them, however on some fuses the Amp rating is hard or impossible to see because it is stamped on the fuse so lightly. Even on fuses with Amp ratings stamped on them deeply the rating can be difficult to see and the fuse may need to be held up the the light at just the right angle to be able to see it.
Voltage matters, right?  I've got one of the 48V 1000W motors on my bike.  I blew a fuse, and have no idea what the rating was, but I had some 30A 12V fuses around to try out.  So far I've blown through 3 of them, always while going up the steep part of a hill.  At the bottom of the ElectricScooterParts.com fuse page, it talks about 32V DC fuses being equivalent to 250V AC fuses... but what it's not clear to me that either are good enough for my bike.  So far, finding a 25A or 30A, 48V fuse has been tough (though I'm sure I'm just a couple links away from finding one).

 

For low Voltage DC fuses the Voltage actually does not matter very much. Amps are equal to Volts divided by Watts, so it does not matter very much what the Volt rating of the fuse is. The beauty of the Amps measurement is that it is Voltage and Wattage independent. The Voltage rating on car fuses is there so that for example a car fuse is not used in a home appliance that uses house current, because the car fuse is not designed for or certified to use in home appliances.

For a 48V 1000W motor I would use a 40A fuse with any Voltage rating. 40A fuses can be hard to find at auto parts stores though because they are not typically used in cars. We sell 40A fuses here though, on our fuses page which you linked to above.

With a 48V battery pack using a 40A fuse you will need to have a minimum of 12 gauge wire running between the battery pack and controller, and the controller and motor. If the bike has 14 gauge wire then I would continue using 30A fuses until the wiring was upgraded.

Here is a link to our wire gauge and fuse selection chart: http://www.electricscooterparts.com/wireandfuseselectionchart.html

Please let me know if you have any questions.

Thanks for the reply, and that's interesting. Does it need to go to 40A due to spikes?


You are welcome, and thank you for participating in our forum.

Yes the Amperage spikes a lot when going up steep hills. If the scooter was only being driven on flat ground then you could get away with using a 30 Amp fuse. But since the 30 Amp fuse is blowing when going up steep hills you will need to use a higher Amp fuse under those conditions.

Please let me know if you have any further questions.
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