Can we charge a 48V off grid battery bank with a 12V car alternator and small gas engine? Video Part 1 was building the alternator generator project: https://www.youtube.com/watch?v=CL8W5hipaLM Video Part 2 was fixing problems, answering questions, and running our first fuel economy test. We also checked for over-heating issues: https://www.youtube.com/watch?v=cy0t4qq8mS0 This video is part 3, and we find the sweet-spot for fuel economy. Video, Honda EU6500 Inverter Generator: https://www.youtube.com/watch?v=kQTFPMDE_F4 I bought a 12V car alternator off of craigslist for $100. Next was a Predator gas engine from Harbor Freight. In this case, I purchased the 224cc MAX engine, which is 6.6hp. The 212cc 6.5hp engine would have also worked well for this build. The goal is to make a dedicated generator that can recharge my 48V battery bank. I'm using the EG4 LiFePO4 batteries, which is a little more than 30kWh. Sometimes, during the winter, the solar production doesn't keep up with my loads. That's when I need to supplement my solar with some generator run-time in order to recharge my battery bank. Yes, 48V generators exist on the market, but they are thousands of dollars. I built this generator for about $400. ----------------------------------------------------- Signature Solar Affiliate Links: Battery Bank, EG4-LifePower4, Lithium, 30.72kWh: https://signaturesolar.com/eg4-lifepower4-lithium-batteries-kit-30-72kwh-6-server-rack-batteries-with-free-pre-assembled-enclosed-rack-with-door-wheels-busbar-covers/?ref=4_rHcgZ9x-TiF- Inverter kit, Schneider XW PRO 6848: https://signaturesolar.com/bndl-ac-coupling-with-single-inverter?ref=4_rHcgZ9x-TiF- Chargeverter: https://signaturesolar.com/eg4-chargeverter-gc-48v-100a-battery-charger-5120w-output-240-120v-input-pre-order/?ref=4_rHcgZ9x-TiF- ------------------------------------------------ Amazon affiliate Links: Thermal IR Camera, Android (used in video): https://amzn.to/3oOxHtE Discount Code Available through the end of April: 05KO745E Thermal IR Camera, IOS: https://amzn.to/4243zJ1 Discount Code Available through the end of April: AQZDUH41 Saw, Circular, Metal Cutting Evolution: https://amzn.to/40Hcyic Hydraulic Crimping Tool Set, Temco: https://amzn.to/3JZmzkv Full Bridge Rectifier: https://amzn.to/3nvZ0In Heat Sink, Aluminum: https://amzn.to/40uxCZQ (Alternate to the one in the video) Thermal Paste: https://amzn.to/3FZ36yX Ring Terminals, UL, Marine: https://amzn.to/3K0N3lw Capacitor, 450V, 1000uF: https://amzn.to/3lTHopw DC to DC Buck Converter, 12V 5A: https://amzn.to/3nug0yK Charge Controller used in this video (Victron 250/100): https://amzn.to/40k4kNz Less Expensive Charge Controller: https://amzn.to/3K4fZJE Vibration Engine Mounts: https://amzn.to/3nmbbaz Rubber Feet: https://amzn.to/40DKsoq Busbar set: https://amzn.to/3M4plYq Circuit Breaker: https://amzn.to/3M3N1w6 Tesa Tape, for looming wires together: https://amzn.to/3TXUrTx Electrical Tape: https://amzn.to/3KkdeVJ Kapton Tape: https://amzn.to/3G2VWKe Bandsaw Blade, metal cutting: https://amzn.to/3M3yro1 Pulley, serpentine belt, 3/4" bore: https://amzn.to/3UaXuYF Serpentine Belt: https://amzn.to/3zlsATu Pulley installation kit, power steering pump: https://amzn.to/3JUeopz Tap Magic cutting oil: https://amzn.to/42PruwW Dewalt Step Drill Bit: https://amzn.to/3G5DwZj Soldering Iron, Large: https://amzn.to/42QY0i6 Solder Wire, Rosin Core: https://amzn.to/3Zvh6aC Flux Pen: https://amzn.to/40qeLPC Wire, Silicone, 12 gauge AWG, flexible, tinned: https://amzn.to/3zonJRq Wire, Silicone, 8 gauge AWG, flexible, tinned: https://amzn.to/3zlkg6u Pen, deep reach marker: https://amzn.to/3M3PKp7 Heat shrink tubing, marine, 3:1 https://amzn.to/3zC7NeR “As an Amazon Associate I earn from qualifying purchases.” ------------------------------------------------------ Harbor Freight Links, Not Affiliated: 6.6 Hp, 224cc, MAX: https://www.harborfreight.com/generators-engines/engines/66-hp-224cc-max-performance-ohv-horizontal-shaft-gas-engine-carb-57493.html Band Saw: https://www.harborfreight.com/power-tools/power-saws/band-saws-scroll-saws/10-amp-deep-cut-variable-speed-band-saw-64194.html Flux Core Welder: https://www.harborfreight.com/easy-flux-125-amp-welder-56355.html Note: I have no affiliate with Harbor Freight. Previous Video making a battery charging generator from a free treadmill motor: https://www.youtube.com/watch?v=DaF6n-9RVT4 Disclaimer: My videos are in no way intended to be instructional "how-to" lessons. I am simply documenting my project for informational purposes. Property damage, personal injury, or death may result, even when following manufacturer's instructions. I cannot be held liable for such damage or injury. It is YOUR OBLIGATION to ensure that you are complying with any local and federal laws as well as code and permit requirements. David Poz, LLC