EDIT/Update: Near real time stats for my setup at wk057.solar. EDIT/Update: Since I started this thread this project has undergone many changes and updates and has turned into something larger than originally described. Most of that info is in later posts in this thread, and I'll try to consolidate some of it here later on. My project has been featured on Bloomberg Business, Hack-A-Day (2), and quite a few other places around the interweb. So, I'll definitely work on getting a summary setup soon. --- Some specs from later on in the thread: --- Update 2015-05-15: Roof portion of my system is completed. Solar Install - 15.7kW Roof System - Final Compilation (Time lapse, drone shots, photos) - YouTube Solar Install - 28.7kW Ground System (Residential) - Part 2 - Final - YouTube --- So, I have this crazy idea about using an 85kWh Model S battery pack (from a salvage Model S) as the heart of a custom off-grid solar power setup somewhere around 25kW DC. I assume others have thought about this... I considered making a setup where the solar panels would be setup in a configuration to produce something like 450VDC+, then making a buck converter for high efficiency charging directly from the panels. The most I've seen the battery voltage was about 404V during a 100% charge at a supercharger, so, this should be possible. Little bit of microcontroller brains to keep things sane and all should be well. Inverter should be simple, since HV inverters already exist. Might need to step the voltage down a hair since a lot do not operate at >400VDC input. But, that's not the hardest part of this project by a long shot. That aside, does anyone have any information about the pack itself? I'm working on physically getting one to tinker with, which will help, but I'd be curious if anyone else has done any of this already and we could save each other some leg work. I'm also wondering if Tesla would sell any of the parts needed to interface with it, such as the high voltage connectors. I might need to just get a full salvage Model S to do this (would be cool, because then I might end up with 170kWh of battery...). Things like hooking to the coolant loop and adding a radiator and things should be trivial. Accessing the existing BMS might be hard, though, but might not be needed. Since the pack will be stationary I'll probably pop the cover off and go from there. Even if the pack+interface items cost say, $40k, thats only $470/kWh. I refuse to go lead acid again for an off-grid setup (my previous much more modest setup used lead acid, and it was just a pain...). But for lithium ion packs of comparable size, you're looking at a price of at least that, plus a lot of labor to build the pack itself. I came up with a cost of around $500-600/kWh using off the shelf DIY EV lithium ion batteries, not counting any assembly or wiring. Anyway, my background includes a bunch of experience with solar and related items, as well as some electrical engineering, circuit design, programming, etc. So, this is a doable project assuming I can get the materials. Just looking for input. (Not sure if this is the right sub-forum, but it seems appropriate) - - - Updated - - - Just to note, part of the load of this system will be charging my Model S. I'd love to get it 100% off grid.