I have a small system consisting of 2 100AH batteries, solar panels, a 30A grid charger and a charger from my tow vehicle.
The batteires can have about 60A charge and discharge max.
Im lookkng for a breaker that i can use.
I don’t fully understand the directionality of resettable breakers so I’m struggling with finding something that will.protect my wiring.
Breaker to be used where in the system?
Just on the battery?
Yes, this is the main breaker at the batteries. My plan is to put it in the battery box itself, so an auto reset breaker that works both ways is the goal. something like this, but that is still polarized.
That one is single pole. Known for nonsense tripping. So be careful with your choice.
You could always fuse one side (positive) and have a disconnect on the other pole.
A double pole is [this one] (Chtaixi 12V-110V DC Miniature Circuit Breaker, 80 Amp 2 Pole Battery Breaker Protector for Solar PV System and RV, Thermal Magnetic Trip, DIN Rail Mount, High Current DC Disconnect Switch MCB 2P B80: Amazon.com: Tools & Home Improvement). I am not a fan of dc breakers their Ka rating is too small for lithium.
Size your fuse/breaker about 1.25 x expected current (rounded to nearest size)
In my humble opinion, there are no suitable, safe, and low-cost DC circuit breakers. The key words are “low-cost”. Properly extinguishing a DC arc upon closing or opening under load is no small feat, especially at high current. And as LX indicated, the interrupting current rating for low-cost DC breakers is too small. Quality DC circuit breakers at suitable interrupting current are very expensive.
Put more simply, use a fast-acting, high interrupt current fuse as close to the battery terminals as possible.
You didn’t give us your battery voltage. At 12V or 24V, use an MRBF terminal fuse on the positive battery terminal. If 48V, use a Class-T fuse or suitable equivalent in your country. If you need a battery disconnect, use a quality DC switch like a Blue Sea 6006.
You might check ABB or Siemens DC MCCB’S
I agree with @OGPS that finding cheap suitable breakers is very difficult. Mine were especially made and fairly expensive. Yes, I looked at ABB and Siemens. They had many DC breakers but they were not suitable. But then, mine is a 48v system.
What i have used from siemens and abb is mostly for 75+ volts and 10kA+ breaking capacity.
Check the Sirius line for Siemens
Ok im looking at this one. 12vdc system with 50a inline breakers elsewhere.
6ga wiring throughout.
This would be within 6" of the batteries. Two LIon batteries, each has a BMS with 300 A max cutoff.
Thoughts?
Westinghouse UL 489 AC Miniature Circuit Breaker, 60 Amp, 2 Pole, C Curve, 10kA, 480Y/277V AC, 125V DC, Non-Polarized, UL Listed, DIN Rail Breaker with Thermal Magnetic Trip Westinghouse UL 489 AC Miniature Circuit Breaker, 60 Amp, 2 Pole, C Curve, 10kA, 480Y/277V AC, 125V DC, Non-Polarized, UL Listed, DIN Rail Breaker with Thermal Magnetic Trip: Amazon.com: Tools & Home Improvement