OK so I need a breaker that will trip at 65A but its going to be at 84V. Anyone know of something that will work? How does different voltages affect breakers. Like can I use a 120v 65A breaker? Will it still trip at 65A?
Since most cheap breakers use a bi-metalic heating element, the trip is at the set current level regardless of the voltage. You can draw it out and do the math yourself, but the resistive metal strip that actually expands generates the same heat due simply to the current passing through it. Voltage in this case is only a reference to the insulation class.
>>940654
>Like can I use a 120v 65A breaker? Will it still trip at 65A?
Yes, if it doesn't have any electronic 'smarts' in it (like GFCI, Arc Fault, etc.) Smart breakers might still work at 85 Volts (how else would they operate when voltage dips during fault). But some operations (like closing) may not work properly.
Mind me asking, what are you planning to do at 84V?
>>940857
I'm gonna guess MOT welder.
>>940857
Im Building an E Bike. It's pretty badass. I had it going last Summer and I starting to upgrade it before it gets nice again and I want to ride it.
It is a 84v battery with a 20ah capacity. A 3000 watt motor. I get around 50wh per mile. So I can go around 33 miles. And I have reached 45mph on a flat.
Its wicked fun!
Pic is old. Lots has changed but you get the idea...
>>941202
wow, pretty cool bro.
very nice compact and "finished"!
can you show us the guts, maybe some specs and parts?
i built an electric skateboard on here some time ago, but this blows it away.
Can you elaborate a little further on what specific conditions you want the breaker to open under?
>>941202
It'll work fine. I used to use one on my bike.
The problem you're going to have is that mains breakers are rated for AC, not DC. AC, because it crosses 0V many times a second, will see a much shorter arc when the contacts open than DC at the same voltage. Basically, this means you have to either derate the breaker heavily for DC use (talking like 1/5 of the AC rating here), or live with the fact that the contact will wear out much faster.
That being said, this won't be a problem if you're not using it to switch an active load and the thing isn't tripping all the time.
I'd recommend just using a fuse, though, if for no other reason than connecting to a breaker is awkward. They're made to be jammed onto a buss bar, and the clip doesn't have any real way of staying in place by itself.
