Tesla might seem uniquely qualified to offer giant packs of batteries that you mount on the wall of your home, but it's certainly not the only automaker in the world making electric cars. That's where Daimler comes in — the German conglomerate is planning to offer Mercedes-Benz-branded battery packs starting this September in its home country through subsidiary Accumotive, and it's taking registrations now.

Like Tesla, Mercedes' battery packs are filled with cells originally designed with cars in mind, and they're designed to even the load so solar energy can be stored overnight and homes can draw from the grid during off-peak hours. The company says that you can combine up to eight packs — 2.5 kWh each, for a total of 20 kWh — which will make it appropriate both for home and business use. (It also seems that the company will be offering higher-storage options in custom configurations for extremely large users.) Similarly, Tesla's Powerwalls can be combined into "Powerpacks" that scale all the way up to 10 MWh or more.

Tesla says it has seen extraordinary demand for the Powerwalls, so it's conceivable that Mercedes' entrance to the market will help spread out demand — and a little competition never hurt. No word on pricing yet, but Tesla's systems start at $3,500.