Will this even work? 48V alternators are expensive. Can we make one from a standard 12V car alternator? I don't know, which is why I decided to try. This video a a complete walk-though, start to finish.
I bought a 12V car alternator off of craigslist for $100. I wasn't looking for any specific model, but I wanted a serpentine pulley on the alternator, and it had to look decent. 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.
Intro:
00:00
Theory of Operation:
00:43
Parts Used:
04:44
Alternator Wiring:
07:04
Building the Base:
16:43
Drive Pulley Installation:
21:05
Wiring the Busbars, Rectifiers, Buck Converter, and Capacitor:
27:45
Test Run:
38:29
Conclusion:
44:20
Amazon affiliate Links:
Hydraulic Crimping Tool Set, Temco: https://amzn.to/3JZmzkv
Ratcheting Crimping Tool: https://amzn.to/3ZnipZm
Full Bridge Rectifier: https://amzn.to/3nvZ0In
Heat Sink, Aluminum: https://amzn.to/40uxCZQ
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
Engine Hour Meter and Tachometer: https://amzn.to/3KhxMhE
Vibration Engine Mounts: https://amzn.to/3nmbbaz
Rubber Feet: https://amzn.to/40DKsoq
Nuts, Flanged, Nylon insert: https://amzn.to/3ZrVMD4
Busbar set: https://amzn.to/3M4plYq
Circuit Breaker: https://amzn.to/3M3N1w6
Center Punch: https://amzn.to/42Q5EJH
Tachometer, Digital: https://amzn.to/3Kl1ken
Tesa Tape, for looming wires together: https://amzn.to/3TXUrTx
Electrical Tape: https://amzn.to/3KkdeVJ
Kapton Tape: https://amzn.to/3G2VWKe
Loctite, Blue 242: https://amzn.to/3zhO6IL
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
Break-in Oil for Engine: https://amzn.to/3nzCG0J
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
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OIl to protect metal, Ballistol: https://amzn.to/3KlZt8Q
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
Tap and Die Set, SAE, Titanium: https://www.harborfreight.com/titanium-nitride-coated-alloy-steel-sae-tap-die-set-45-piece-61411.html
Note: I have no affiliate with Harbor Freight.
Previous Video making a battery charging generator from a free treadmill motor:
https://youtu.be/DaF6n-9RVT4
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-
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