I think a U-1 size battery (Garden tractor battery) would fit and work just fine, in a Fit.
It has 340 cca's. My orig. battery has 350 cca's. The size is about 1/4" longer and wider, and it's shorter.
Sears sells one for $50.
Unless you left your lights on, it should work fine.

 

Try it, report back results.

 

Being as my orig battery is only 3 wk's old, I'll wait a while!
Too many things I need to do, to start doing things I don't need to do!
I installed one, in my runnabout, with a 25 hp motor, and even when The fuel pump quit, It cranked that motor for a long time, without starting to slow down, before I decided I need to fix something.

 

over40pirate being a JB fan?

 

Does it have normal battery terminals? most lawn or industrial batteries have tabs with bolt holes in them.

Not that it would be difficult to make work.

EDIT there is also this!
http://www.aiconsol.com/svr20-12-svr...d-battery.html

I have one, I am going to be using it as a main battery once my stock one goes bad. My engine starts already are starting to take longer, even though the headlights still refuse to dim when I hit a strong bassline (granted I hardly ever crank the crap out of it)

 

They do have bolt on tabs. I think anyone who can do more than push pencils, could figure out a way to make it work.
Might even be able to kust clame the orig ends over the flat terminal on the battery.

 

Id just cut the terminal off. It has a nice bolt on the arm that I used for my 0 gauge alt wire and 4 gauge sub power wire. Id just get the amp ratings of the honda fuses and make a fuse box to replace the big bulky positive terminal assembly

 

The only reason I might not the terminals off, is in case I decided to get a larger ah battery.

What do you mean by; "make a fuse box to replace the big bulky positive terminal assembly"

 

Go to O'reilys and get the terminal adapters for the lawn and garden batteries. I did the same thing to my old civic and it works fine. The battery does not last long if left on with lights and it kills the entire battery. This is a good cheap replacement to the expensive oem battery.

 

Saw Garden Tractor battery at Tractor Supply, on Sat. with 400 or 420 cca's for $50.