Hey! I was wondering, does anyone know which exact battery I should buy for my car? It is a 151r correct?

 

Type 151 is the one Honda supplies and you certainly could get another one. But a lot of people find that a Type 51 battery is more powerful and/or easier to find and/or less expensive. Fitting that one, though, requires a little hacksaw work on the tray that holds the battery. I'm sure instructions to do that are somewhere on this site if you think that upgrade makes sense for you.

 

Just get a stock size Diehard Battery.

51r Battery is unnecessary.

 

I went crazy and installed Mega-LiFe MV-19L (Group 151R) on mine.
The factory battery was still working after 5 years, but it was cranking pretty slowly, and I wanted a lighter battery, so I went for it.
I wouldn't necessarily recommend it for daily drivers, especially considering the cost.
But it's been fine for me.

 

Swap in the 51R battery and you will never look back. 1) modify the tray 2) swap in the tray that would allow for the 51R battery 3) take the tray out

 

For those searching (as I just was), it's the tray for the '15-17 Fit, 31521-T5A-000. The '18-20 version (-T9P-000) has a cut-out to brace the 151R against sliding around in the tray, which prevents the installation of a 51R battery.
Looks to me like the engineers knew they were pushing the limits of the 151 battery, so the pre-refresh models had the option to drop in a larger battery if it turned out it was a problem. A few years in they were confident enough about it to make the tray 151-exclusive.