40v Power Inverter 300w

I'd like to get a power inverter to continually use the 40v battery, for which I currently own only one tool, since the battery warranty is shorter than the tool's. I thought I'd start by investigating the power supply unit (single) sold for the 40v and running it routinely, then of course using it for the trimmer outside come summer.

If anyone has tried a generic 40v inverter with real Ryobi batteries, I'd be curious what results you had.

Thanks in advance.