1000W 12V –> 220V Inverter
I have to admit that I <i>really</i> dislike using ~12V batteries for high power applications like this.  I say this having built a ~400A ~14V system.  It’s miserable.<p>1 kW at 100V or 250V or similar uses a nice, small, flexible wire. It can be quite safe because it can be fused or otherwise protected at low currents, which mitigates the risk of welding things, starting fires, or arcing. Ground fault protection, arc fault protection, and general loss-of-isolation protection are available. It’s easy to rework (lever nuts! screw terminals!).<p>400A (or even 80A or so like in this article) is a whole different ball game. Sure, you have to work hard to electrocute yourself. But you can easily set things on fire or weld things together without coming close to blowing a fuse. And you need to protect <i>both ends</i> of wires in a parallel arrangement.  And the wires are enormous, expensive, and hard to terminate.<p>I would much prefer one of three alternative designs to become popular:<p>1A: a <i>series</i> arrangement of batteries at a civilized 48V or so. You can do this with an aftermarket BMS, but they tend to be janky.<p>1B: same but actually high voltage (a few hundred V, like an EV)<p>2: batteries with microinverters and a civilized way to share current. A manufacturer could make a single package with a 1kWh battery, a BMS, a low voltage, low current DC auxiliary output, and a ground-fault and overcurrent-protected 110-250V AC input&#x2F;output.  And an RS485 or 10BASE-T1S or CAN connection so that they can coordinate their I-V characteristics to appropriate distribute charge or discharge current.<p>Now you can connect as many microinverter-batteries as you like in parallel, using #14 wire, to one ordinary circuit breaker per battery plus (depending on the overall arrangement) one big breaker to protect the common bus.<p>edit: Also, with this design, no one, not even the manufacturer, needs to touch a heavy-gauge wire. Everything in the battery would use cheap, painless busbars or small wires, depending on the internal voltage, and the manufacturer could set the voltage however they like. Although 12V internally might be entirely reasonable if the end user also wants to consume 12V at very low currents through the aux output.