The author is concerned about the embodied energy cost of a larger battery, so has a smallish battery which only lasts about a day. For my small solar powered

The author is concerned about the embodied energy cost of a larger battery, so has a smallish battery which only lasts about a day. For my small solar powered installations I generally use a lead acid battery with a zero embodied energy cost. When I pull a starter battery out of a vehicle, instead of immediately recycling it I use it as a storage battery for one of my remote solar installations, sometimes adding it in parallel to an existing one. They can then perform for years as a bad, but useful, low current storage battery. Eventually something horrific¹ happens or a cell goes completely² and I recycle the battery. So the lead and the sulphur spend a few years longer between reincarnations as batteries, but the embodied energy is zero for my use. ␄ ¹ A camera/weather sensor station went offline after an unusually strong storm from the south. I suspect there was unprecedented wave erosion and dropped it off the embankment. When the site becomes accessible again I'll probably find it in a heap at the shoreline with ruined batteries from freezing. (Sometimes I lose the sulphur, but there is a world sulphur glut so I don't feel too bad.) Other causes of demise are failed solar chargers or stuck on loads, usually from wiring failures. (darned rodents) ² I'd like to make a lead acid charge controller which can detect a shorted cell and just call it a 10V battery instead of a loss, that would extend their lives. There is DC/DC conversion already happening at charge and discharge, so it shouldn't hurt efficiency significantly.