September 6, 20232 yr If a lower power hybrid ups inverter (1.8Kw) is added to my chain, can the inverter be bypassed when the demand exceeds the inverters 1.8Kw output? As far as I understand, the hybrid inverters role is to get power in the most efficient manner from the available sources (solar/utility/battery) but I'm not sure if I'm limited by the size of the inverter? I just want a basic 12v backup solution for TV & wifi that compliments my current noisy generator solution which will only be used for anything over 2-4 hours... I'm currently testing the unit manually with a 3 way multiplug for AC out & 3 pin plug for AC in & the load is sometimes over 200w. Would it be worthwhile to add the connectivity straight to the db board so that I can add the lights as well? This is basically just a UPS solution & if the bypass function will allow me to just automatically switch the source for higher loads (microwave, washing machine & dishwasher), then I will connect straight to db board...I will obviously leave out the geyser switch & can leave out the kitchen plugs switch as this is where the big appliances stay.
September 17, 20232 yr Sadly, they typically rate the internal changeover relay to about the same as the maximum output of the inverter. So if it's a 1.8 kW rated unit, at say 2.0 kW it will soon end up stopped with an overload fault code and no output. I know that's now what you would want, but it's cheaper that way. Even 5 kVA models with 40 A relays behave that way; they don't let you get close to the 40 A that the relays are supposed to be rated for. 40 A at 220 V is 8.8 kVA, which would be a nice overload capability. I think it's because it's cheaper to use PCB tracks than to wire the relays properly with bus bars or actual copper wire and crimped connectors.
September 17, 20232 yr Author Depending on the inverter but I doubt it. What is the inverter model? It's a Chinese inverter branded Inkwenkwezi... I tested adding a 2kw load after your reply & it beeped with a fault code.
September 17, 20232 yr Author Sadly, they typically rate the internal changeover relay to about the same as the maximum output of the inverter. So if it's a 1.8 kW rated unit, at say 2.0 kW it will soon end up stopped with an overload fault code and no output. I know that's now what you would want, but it's cheaper that way. Even 5 kVA models with 40 A relays behave that way; they don't let you get close to the 40 A that the relays are supposed to be rated for. 40 A at 220 V is 8.8 kVA, which would be a nice overload capability. I think it's because it's cheaper to use PCB tracks than to wire the relays properly with bus bars or actual copper wire and crimped connectors. I'm currently using it as a UPS & the transfer time from grid to battery has been sufficient enough so I was hoping that the overload bypass would be good enough for me to connect it straight to the db board so that there's never an issue while the grid is available but I know now that it's not feasible...bigger inverter required.
September 18, 20232 yr It's a Chinese inverter branded Inkwenkwezi... It's a clone, so practically all hope of a high rated relay are gone. But you proved that with your 2 kW load test.
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