I’m thrilled with the results of this conversion. It has higher torque, more power, runs quieter, can run an electric PTO, goes for an hour, has a light bar and USB device charging. Best of all, there’s no exhaust fumes and no gas to pour. Just the sweet smell of a freshly cut lawn.

Some common questions:
How many amps does it draw while running? IDLING: 10; DRIVING/TOWING (no blades): 1215; MOWING (weekly maintained grass): 2025; MOWING (heavy long grass): 28ish; MOWING (heavy crazy jungle overgrown): 3035
How long does it last on a charge? About an hour on kinda/sorta maintained lawn.
The above doesn't make sense! You have 100ah at 48v! Why doesn't it last longer? Well, at 2530 amps of draw, I run for about an hour before I notice degradation in performance. My batteries are a few years old and SLA batteries start to show lower performance (in my humble experience) around 5060% and I don't like to push them much further. I'm sure I could run for a couple hours if I'd used lithium, but if I'd done that I wouldn't have had money for anything else and my wife never would have approved :D

Links to the parts (if I forgot something, leave a comment and I'll add it or find it):
Motor: Motoenergy 1004. It's a 48v DC motor with terrific torque and a vertical drive shaft that's the same size a lawn tractor. It was designed with the intention of being a direct conversion. You can get them from a few suppliers, sometimes on Amazon, and sometimes eBay. I got mine for about $400. I see them mostly around $600 now.
100ah SLA battery (I got mine from a failed EV company that liquidated, but I've bought and used these Mighty Max ones in other projects): https://amzn.to/3868wqF
48v heavy duty solenoid (400A): https://amzn.to/2WhwHAc
2 gauge wire (can handle 205 amps): https://amzn.to/3sDJAjG
6 gauge wire (can handle 115 amps): https://amzn.to/2UEgRPe
12 gauge wire (for the 12v stuff): https://amzn.to/3sJZ4mj
Heat shrink tubing (hint, I only used the black and red, but wish I'd color coded and would do so next time): https://amzn.to/384isRJ
DC Multifunction Battery Monitor (0200V, 0300A): https://amzn.to/3DeEvn8'>https://amzn.to/3DeEvn8
Battery Fuel Meter (48v): https://amzn.to/3870D4m
12v meter + USB charging: https://amzn.to/3khf2AA
Terminal blocks: https://amzn.to/3DeEvn8'>https://amzn.to/3DeEvn8
Terminal boots: https://amzn.to/3gssiRX
48v step down transformer to 12v: https://amzn.to/3sDANyp
Battery keys: https://amzn.to/2UHwMfR
Rocker toggle switches: https://amzn.to/3BjqeDV
48v golf cart charger (there are other options, but this one was a good balance of quality and price): https://amzn.to/3glUJRt
Golf cart charge port (female): https://amzn.to/3Da08Vk
Golf cart charge cord connector (male): https://amzn.to/3mp6cmW
Light bar (16"): https://amzn.to/3sCPi5y

Links to the tools I use:
Label maker (so insanely helpful on electric projects): https://amzn.to/3kbd84w
Test light: https://amzn.to/3gqCjiB
My favorite multimeter ($30 and works great): https://amzn.to/3zdpVJR
My hated multimeter ($8, works, but why didn't I just get the good one first?) https://amzn.to/3sDKOvi
My favorite wire strippers: https://amzn.to/2WiBW22
My least favorite big crimpers, but they get the job done: https://amzn.to/3B2I7qg
10, 12, and 14 gauge crimpers: https://amzn.to/3yfCWBj