Fuse for Ebike Kit 1000 watt Waterproof Connectors Hub Motor Conversion

[Tedd]

I'm using a 48 V battery that I already had to power the "Ebike Kit 1000 watt Waterproof Connectors Hub Motor Conversion" that I just bought. I forgot that the battery has a built in 20 A fuse, which isn't quite enough for a 48 V 1000 W motor. I'm thinking of upgrading to a 25 A fuse but wondering what Luna Cycle recommends for this kit?

Tedd

[paxtana]

Sure i think a 25A would be fine if it's the sort of thing where you can change that out. Maybe 30A to be sure.

[max_volt]

Isn't the built in fuse supplying the maximum amount of current and would not you be in danger of damage if you attempt to arbitrarily exceed it?

[Tedd]

This battery pack is from a factory-made ebike, and it's my belief that the fuse is there to protect downstream devices in the original bike, which no longer exist. All that's downstream of the battery now is the Luna Cycle 1000 W kit, which I assume was designed for the current it draws. I've dismantled and examined the battery pack and discovered that the circuit the fuse protects doesn't pass through any of the electronics within the battery itself, it goes straight out through the connector. I have not yet checked whether the wires in the fuse circuit are of high enough gauge to handle more than 20 A, though, so that's definitely worth doing.

[paxtana]

I think we would have to know a lot more about the battery be sure one way or the other. Only thing we definitely know is that if he is using a ebike kit that is pulling 25 he's going to blow that 20 amp fuse all the time. It's definitely not the ideal battery for his situation and he will get less cycles but he's most likely stuck with it for now until he buys from a more reputable battery supplier. Only reason I can think of that the company would put a 20 amp fuse on a battery pack would be because they cheaped out on the cells and used something with a less than ideal discharge rate, most likely a Chinese supplier. Good luck trying to ship a battery back to China for an exchange.

[max_volt]

I was screwing around on ebay and ended up with a questionable battery that has a 5x20mm 20A fuse. After getting some spare fuses from the only place in the whole metro area that had them, I can report my display on the bbshd showed well over 25A draw and the fuse never popped. I am heavy and I took it up hills and across fields.

[paxtana]

I think it depends on how long you are peaking above the rated current for the fuse and the type of fuse. I still don't think it's ideal but glad it worked for you.

[Tedd]

Thanks to everyone for the comments. I think I accidentally sent this by pm so I'm re-sending it.

The ebike in question is a factory made bike that I have gutted the drive from and replaced with a Luna Cycle 1000 W kit. (Long story.) The battery is from the original ebike and, so far as I can tell, the function of the fuse in the battery was to protect the original 500 W drive system. The circuit the fuse is in goes straight out to the connector, and the battery electronics appears to have separate protection. So the only risk to a higher-rated fuse seems to be the wire gauge in the fuse circuit itself. I do plan to check the current rating on that wire, but I haven't actually done that yet.