So about 5 years ago my OEM battery crapped out and they didn't have it at Costco so we got a 51R thinking we'd be able to switch it out no problem. I didn't know much about cars at the time (doing my best to learn now) so my friend said he could handle installing it after I noticed it was too big for the battery tray. It wasn't until recently that I finally noticed how messed up and potentially dangerous this installation is. It's touching the air filter cover and now both the side tabs are broken off, and the insulation on the positive cable is getting pretty badly damaged as it is wedged very tightly, although it still has some give if I push it back.

I'm now very nervous about driving it and know I'm very stupid for driving it like this for so long, but also I'm new to working on my own car and have brought it into the shop like 10 times for other issues/tune ups/oil change etc. and unfortunately no one brought it to my attention

I found this video where they modify the battery mount so that it works with this battery but the battery in the video doesn't have the fuse on the positive terminal and after looking at it a bunch and measuring stuff I'm not convinced it's going to fit in there so am hesitant to go and saw off part of the battery mount.


I'm really broke at the moment so if this fix worked it would be the best option as I only need to buy a new hold down (hold down and plastic battery case were lost at some point over the last 5 years)... I know this is a common mod so I would prefer to keep the 51R if possible, especially since I don't think it will fail anytime soon. I think to do this I would need to ditch the fuse which doesn't seem like a great idea. I live in SoCal so I don't think it's as necessary as it is for some people but it's going to be pretty expensive (need to purchase 151R, battery case, and hold down) to downgrade.

With that said I'm most concerned with safety and possibly damaging other things but am unsure what the move is. I don't want to bit the bullet and downgrade just yet, but also don't want to saw off the battery mount just to end up having to remove the fuse box and compromise safety in a different way.

Looking for advice on what to do, if anyone has done this mod with the same setup, and maybe some advice on what should be done about the air filter cover and damaged insulation on the battery cable. Although there's some stuff out there on this mod I haven't seen any threads/videos addressing this specific set up with the fuse box...

Thanks ahead of time for any guidance here, I'm down pretty bad atm so please take it easy on this idiot

 

There is a battery thread on here were I put all details of what I done.

Basically, 00 Civic battery undertray (10$ ?), 1-2 layers of rubber mat with holes where the undertray has "spikes" so everything sits flush and tight (kind of what you put under exercise machines to protect the floor - 10 $ and you'll have spare). On the positive cable, a cable extension that on one side has the OE battery post size and that you connect to the OE positive battery cable and on the other end a clamp that goes on the 51 battery post (15$ ?). There is still a 1-2 mm clearance on both side of the battery with this setup (keep in mind that battery size can vary a little bit, so that was the case with a Canadian Tire battery).

Don't have my Fit anymore, so no receipts or no pictures possible, sadly. There were links in the original thread, but can't find it. Probably posted it in 2015 or 2016 I guess, after I replaced the 151R battery twice...

Hope this helps a bit.

 

Looks like a Group 51 (no R) battery would be a better choice for the 2G fit. It's the same size as the 51R, with the battery terminal polarity swapped. Or rather, the 51 has the OG polarity, the R has swapped polarity. The 51 would let you turn the whole battery around so the terminals are on the front-facing side of the battery. That would free up a few inches of battery cable length and maybe get the positive terminal away from the air box.

 

I got a 51R battery. It fits, but is tight. hard to change your air filter without taking the battery out.
To install: Just take the battery box out and put a piece of wood under it to raise it up a little. Just some thin scrap wood I used. I ran it without the wood for a while, but it makes it hard to connect the positive battery terminal. I damaged mine from not being able to make it flush. I later replaced it when I changed the starter.