September 23, 20223 yr Hi All Please help me understand.. Assuming you have a single modern lithium battery / inverter setup: The battery has BMS and limits max output, and some also have circuits breakers Inverters has a fuse on battery input and/or over current protection Why do you need the external DC battery fuse? In what scenario would it be needed with this setup?
September 23, 20223 yr Because MOSFETs like to fail short-circuit, which means the BMS can fail in an unsafe way. I would not trust a chinese-sourced breaker with the power to burn down my house. You also need a DC disconnect by law. The correct fuseholder will also perform this function and it is the cheapest option. But if you like housefires I could see why you would want to skip this part 🤪.
September 23, 20223 yr Author Thanks I just wanted to understand why. If you look at the smaller battery / inverter systems they don't use a battery fuse. Is there a certain size/amps where it becomes a legal requirement? Edited September 23, 20223 yr by Brendonvdh
September 23, 20223 yr 15 minutes ago, Brendonvdh said: If you look at the smaller battery / inverter systems they don't use a battery fuse. Are you talking about the ecoflow-type systems? I'm pretty sure they will have fuses.
September 23, 20223 yr 15 minutes ago, Brendonvdh said: Is there a certain size/amps where it becomes a legal requirement? Well, when you have it wired into your house wiring, it falls under SANS 10142 ("The wiring of premises").
September 23, 20223 yr Author 7 minutes ago, P1000 said: Are you talking about the ecoflow-type systems? I'm pretty sure they will have fuses. Like these https://www.geewiz.co.za/long-run-ups-inverter-battery/5373-2400va-mecer-inverter-2x-100ah-batteries-trolley-8-hour-battery-life-kit-1440w-150-200-cycles.html I'm sure there is an internal fuse in the inverter, but why would it not also require an external fuse? Edited September 23, 20223 yr by Brendonvdh
September 23, 20223 yr Author Sorry I replied before I saw your 2nd reply about the house wiring. So the risk of fire is the same, the legal requirement applies when directly wired. Got it. thanks,
September 23, 20223 yr 12 hours ago, Brendonvdh said: Thanks I just wanted to understand why. If you look at the smaller battery / inverter systems they don't use a battery fuse. Is there a certain size/amps where it becomes a legal requirement? From my 750 1000 1500W pure sine all have internal fuses.
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