Anyone know how to figure out how large a circuit breaker you need?
My bike is a 60 volt system with a 2000 watt engine.
Came with a really crappy Chinese Breaker in 45 amp ([DZ47-63 C-63] if anyone knows about Chinese breakers).
Same amperage, quality single pole, molded case breakers go for well over $100.00!!!
30 amp is much cheaper and easier to find if that would work. Thanks!
the circuit breaker is there to protect your wiring in the case of a short.
so the real question is how thick is the wiring between your batteries?
the other major point is you need to get a breaker that can actually break the fault current your batteries can produce.
for AGMs, multiply Ah by around 20.
so 40Ah batteries means you should have a breaker of at least 800A breaking capacity.
low trip rating breakers (like 30A) may not have that breaking capacity.
another major issue is the breaker must be rated for DC (your average mains AC breaker is useless above 20V DC)
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
As Matt said, be very careful of manufactures rating. Make sure it is DC rated and most Heinemann Circuit Breakers are rated for DC but the price may grab your wallet. I used the big 400 Amp Heinemann Circuit Breaker in my truck with Bussman fuses of 500 Amp and the breakers always were resettable. I put an ammeter in my small scooter and did 20 to 30 amperes on 2000 watt motor controller. So 45 amp seem to be right ratio. The DZ47 series seem to be the best for the monies. I have them on my Chinese gen sets too. Wire size will help determine amperage of breakers also. 10 AWG can handle 30 amperes but maybe 50 or 60 amps for a second or two. Most EV's base wire size like older welders 20% duty cycle.
KB1UKU
Ok thanks for the reply's. Found the solution by using a marine DC breaker from Blue Seas Systems. 50 amp breaker rated for up to 80 volt in DC, 3000 amp trip rate. Cost around $25.00 from a brick & morter store "Marine West" (there are quite a few around the country). Everything seems fine on the breaker front now. :)