Okay so I was set up and about to do this:
Then I was like, "oh crap the lawnmower's in the way." Lawnmower wouldn't start, "better get out the battery charger." I flip up the seat to find the battery in a sad state. Loose terminals, and looks to be in backwards with the cables stretched and contorted in weird places. Oh yeah, and nothing was holding the battery down. I'm not so interested in having a lead acid battery explode under my ass, so I went down that rabbit hole to fix it kind of proper. I can't really justify spending whatever the John Deere dealer wants for a bungee cord of the correct length that will probably dry rot and snap in a couple years anyway, so I decided to make an automotive-style battery hold down clamp with the following pieces of hardware I had laying around.
The one in the horseshoe shape looks like it used to be a battery hold down in another life. I'm not sure why I bent it like that, but it'll get another go at holding batteries down. I shortened it and put a new hook in it. The other piece I'm not sure on, maybe some door hardware, but I lopped off one end, threaded it with a 12-24 die and widened the hook on the other end. Both pieces came out pretty good.
I even found a nylock nut for the automotive one, with the ubiquitous 10mm hex. The 12-24 one I just used a regular nut and backed it up with a jam nut. Lots of vibration on these machines, so you need something to keep the nuts from backing off. I think these will work better than the nothing that was there before. Not exactly pretty, but definitely way beefier than they need to be.
The length of shiny stamped steel on the top that I'm using as the hold down bar there is a repurposed socket organizer do-hickey that I drilled an extra hole into and removed all the socket holders from. I also rotated the battery 180 degrees so I could properly route the cables with none of them under tension and out of the way of moving parts (unlike before). All terminals were cleaned before assembly and I stuck it on a battery charger for a few minutes.
A little aside, if you ever disconnect a lead acid battery with lead terminals for more than say 15 minutes, it's a good idea to clean those terminals before assembly. This is true even with a brand new battery, since lead will form an oxide layer in just a few minutes, messing up your contacts every time. I learned this the hard way many years ago tracking down charging and starting issues on my first car. I talked to my father after chasing my tail for days and he told me this little bit of trivia while I sat there with an incredulous look on my face. Turns out he was right, and cleaning the terminals on my brand new battery fixed that problem. This knowledge has saved me quite a bit of money over the years, since I don't just go out and start buying new parts when I have a hard starting issue, I start with cleaning up and tightening all the terminals.
The lawnmower started better than it has since I bought it a few weeks ago, so I think I shouldn't have any more issues with it for a while (hopefully). That's the good news. The bad news is that I didn't get to installing my lift because of the shoddy work of the last guy who worked on the mower. Oh well, maybe I'll get some more done on the lift tonight. For now, off to a picnic.