very very helpful. thank you. . I have a 2008, and I'm going to get a 121R next week. I found your explanation of the install, and your explanation of the terminal confusion, most helpful.

 

Thanks, hope my pics from previous post helps to visualize this install.

Note: The front J Bolt does not go through any hole, but there is a detente under the bottom lip of the tray just about where the hole is.

The one pic does not really highlight this but does show it to some degree.

 

Just had my first engine crank issue on my original 2007 Fit Sport. This was purchased in Sep.'06 and the battery was the original, so well over 10 years old. Started right back up with an emergency battery booster pack.

Figured it was finally time to replace the battery though, and they put in the tiny 151R. When I told the mechanic the original battery was over 10 years old he went bug-eyed and made me feel like a negligent parent.

 

THANX FOR THE INFO!!! I was wondering why my fit had a battery in it that clearly didnt fit and found the battery cover in the hatch. i will check today to see if in fact it is a 51R

 

So I just replaced my 2013 Honda Fit stock battery with a 121R, based on the encouraging posts here. I tried to get Walmart and several other shops to do this for me, but all said it was against company policy to make modifications, even at the owner's request. So I bought a battery wrench and proceeded to do this myself. However, halfway through the conversion, I discovered that the stock, L-shaped positive clamp assembly would not reach far enough over the edge of the new battery to clamp around the terminal. No one mentioned this in earlier posts, so I assume there are differences based on which year of Honda Fit. The only thing I could think to do was buy some kind of clamp extension or wire. The store only had a marine battery clamp extension, which had a flat connector with a bolt, washer and wingnut on the other end, yielding about 2" or so extension. Now, I just had to figure out how to connect to the stock battery clamp. I ended up removing the original clamp bolt so I could spread the clamp halves apart. Then I twisted on the half clamp, rotating it 90 degrees, then widened its hole to fit my new bolt-on extension clamp. It worked! I previously completely removed the plastic battery container and placed two hard sponge abrasive pads between the battery bottom and stock frame. This allowed the battery to not hit the metal frame edges. I also had to bend the diagonal metal brace away that held the battery cable bracket so that it, too, would not prevent the battery from fitting. Pretty proud of myself, but I only did it myself because no one else would!

 

I had a 151R (EverStart) from Wal-Mart it died after 3 months. 3 tests by AAA and 2 Wal-Marts showed it as must be replaced. They would not give me my money back at Wal-Mart so I went back to the Interstate based 151R from Honda which gives you a 100 month warranty. I have always heard good things about Interstate. Beware of the service at Wal-Mart it is not customer focused at all.

The batteries too are not necessarily the best. The battery at my dealer was just $15 more than the Wal-Mart battery but has a 100 month pro-rated not 60 month warranty, that essentially is a better deal.

Costco generally does not provide 151R batteries. I believe in this case the Honda Dealer is your best bet for a battery that they stand behind. Also they will do a charging system check a lot better than most in case your battery is being destroyed by the charging system.

 

After reading every article I could find on this, and seeing that the 51R on an angle appeared to be the best solution, I researched the occasional mention of the 121R and.....it seems to be the best of all worlds! Minimal changes or mods, and a far better battery all around with much better CCA! Wonder why Honda didn't go this route...?! Few pics of the install.

 

The original pooped out just before 3 years, and Honda dealer replaced with new in July 2016. Then that one pooped out in December 2020. Independent shop replaced with NAPA size 151 and it's going fine. I do way too much stop and go driving, now that i have retired., so I'm no sure how much more I'll get out of my current battery.

Since you mentioned q100K, have you replaced the serpentine belt or timing chain?? (Just wondering.) TY

 

Ask and receive.

 

Ha! No need to feel that way. Replace a battery only when it stops working. I recently replaced the battery in my Tacoma at 11 years.

 

 

Not trying to steal your thread, just want to put out an alternative to the 51R battery

I just did a dual xp750 battery modification to my fit.


From what I seen , the 51r battery barely fits, and has to be mounted on an angle pointing towards the headlight...(at least the one I saw was setup like that). There isn't a lot of room there though to begin with in all honesty.

With one of these batteries, cranking was fine and did the job, and is light as hell too. BUT.....when we had this recent cold snap and temps dipped into the negative or near negative temps, the battery lacked some power and I had to keep jumping it from time to time with one of those mini battery jumper things. Apparently it didn't need much of a jump though, due to what those jumper battery packs put out. So, I started eyeballing up how to fit in two of these little batteries in the same area that the stock battery sits in.
This new base/tray will accommodate a battery that is 7.5 ( wide, 6 depth x 6.5" tall.
(With a little bit of milling on the top part of the one I made, you could squeeze in something that is 6 1/4" in depth, but thats pushing it).

Also noticed, the colder it got, the more starting issues I was having, and hearing the starter lag in its actions in both directions (engaging and disengaging the flywheel.
Now, even though the temps are better lately, the car starts up like a champ, and the starter doesn't hang up at all either.

Btw, I'm planning on making more of these if there's an interest...

 

The OEM battery base/tray is held in with four 12mm bolts. Two from the top, which have to come all the way out, and two from the side (which are a pain to get to, due to the lack of space). You'll need some extensions on your wrench to get to them. I'd suggest spraying them with wd40, kroil, or crc knocker loose prior to digging into this project.

I'd also recommend after you get the bolts out to chase the threads out to get whatever crap in in there and use some antisieze when reinstalling them.

As far as the the new tray goes for the 51R battery, I think some people have sourced it from a civic or other Honda that uses that battery type...?
And then grafted the top part to the fit battery base bracket after modifications to that...(The sides on it have to be cut off for the larger metal tray piece to sit flat onto it). There are videos on YouTube you can watch to see what other people have done.

Another alternative is to do like what I did to my fit. (See my post I made in this thread).

 

As long as the charging system is in good working order and the battery is kept clean....they should last a good while. My other car (2005 Dodge Magnum rt) had an original battery. I've had the car since 2014, and only replaced it like four years ago with a much better stinger spp2150 battery.

👍

 

Damn, that's a tight fit for that battery.

 

The battery tray we're using is sourced from a different year Honda Fit. It almost falls into place because it was designed for Honda Fits and they didn't over-engineer it to make for crazy mounting brackets that can only be accessed from inside the intake manifold or like that.

I'll recommend against WD-40, since it performs terribly as either a penetrant or a lubricant. Instead, one might try (PB) Blaster if anything is rusty or a little ZoomSpout oil if something needs lubrication (ordinary motor oil or Marvel oil will suffice. Even ATF.). I'll also recommend against retapping any bolt holes unless really necessary. Removing a rusty bolt already leaves a very slightly oversized tapped hole, and anti-seize doesn't afford much rust protection.

"Good working order" is a subjective phrase, and it doesn't take into account such things as temperature extremes or short-trip drives or even undersized batteries, like this damnable Group 151R that Honda decided to foist on Fit owners for a few years (in other years they installed Group 51s with much higher capacity and CCAs). I got only 6 years out of mine (no jumpstarts), compared to the Group 24 in my Tacoma that got me through for 11 years this last time, even with a couple of jumpstarts due to midwinter idle time.

If you were getting problems with sluggish starter engagement / disengagement,then your starter will want attention this spring; that's the solenoid / Bendix dragging, and it has nothing to do with battery voltage or capacity. Actual cranking speed... that's what verifies a battery.

I've gotta' say... that pair of xp750s makes for a tidy install. Costs more, based on Amazon's price, than just replacing the Group 151R with another Group 151R, though, and they appear to be so "fresh" that they don't even have a review profile on Amazon yet. Can they stand up to the rigors of engine-bay service? Is that really a 30-day warranty, compared to Interstate's 5-year warranty? Where do you take a battery to exchange it for warranty? I can swap an Interestate Group 51R right here in town if it fails early.

 

From what the older generation fits battery base/trays look like they look to me like they bolt up differently. The 2009-2014 have four bolts that mount directly to the front frame rail. I looked at the older and newer fit battery tray/bases, and they have a different shape and appears to have a different bolt pattern. But hey, I'm somewhat new to having these cars soz the more I work on them the more I'm learning about them.

I do believe you misses what I said and automatically thought i said tapping the threads. I mentioned chasing the threads. Little bit different than cutting new threads.

Also, the sluggish starting comment.....
As I said, I wasn't having an issue with starting until the cold snap started. Car was fine on just one of these xs batteries.

Also, when the battery is subjected to cold temps, voltage diminishes...which will cause the lazy starter issue. That I mentioned. Since then the weather has warmed up...and even though I have two batteries nset up on this car ..it's flawless now.

Also, just for the hell of it, and the fact I'm into doing this stuff, I have a higher amp alternator I bought a while ago to put into it as well, to pair up with these batteries and the wire upgrade I've done on it..

Also, thanks for acknowledging my install of these batteries while simultaneously crapping on it. I appreciate it.

Again, I'm new here so, thought I'd get some insight on these cars and what others are doing with them.
Condescending tone, not withstanding...

These batteries have been doing great. You might want to look them up, not just in Amazon. I bought them mainly due to the CCA is a bit higher than most other batteries I've seen for this car (speaking of the stock one.l that is). I also bought them because of the weight savings.
I'm not worried about the warranty since you bring it up. By the time these batteries end up at the end of their life, I'll get more than my fair share use out of them, and I can order two more and have them at my door in just a few days.

You also mentioned the rigors on engine bay service ....been in the car for over a year now....so....yeah.

 

Posting an alternative solution to a problem is generally seen as advocating for it. "Here's my better solution." If you don't go into the why's, how's and generally write a balanced discussion of the pros and cons of your alternative, other forum members are going to do it for you.

Better cranking amps: On the XP750 product page, XS only provides a value for something they call "max amps", not the industry-standard "Cranking Amps" or "Cold Cranking Amps" that have well-defined testing procedures. Two XP750 batteries in parallel should provide 1500 "max amps". XS also sells a 51R sized AGM battery (D5100R). Its product page lists max amps as 3100, and also lists Cold Cranking Amps as 767. If we assume the same 4:1 ratio for max amps : CCA, that puts the dual XP750 setup at 375 CCA. Interstate Battery (first that came up in a search, no affiliation or preference given) advertises their mid-grade flooded lead-acid non-AGM (aka "vanilla car battery") Group 51R "MT-51R" as having 500 CCA - 33% more than the 2x XP750 rig. Interstate's top-of-the-line flooded 151R (MTP-151R, no mid-grade option available) is spec'd at 370 CCA - that seems like a much closer comparison.

Reserve Capacity: The XP750 lists 28 minutes reserve capacity (how long it takes the battery to drop to a standard cut-off voltage with a 25 amp load). The reserve capacities of two XP750's in parallel should add, as they're sharing the load, so 56 minutes. The Interstate 151R lists 57 minutes, 51R is 85 minutes, D5100R hits an impressive 131 minutes.

Lighter weight: The XP750 is listed at 14.5 lbs. Since there's two of them, 29 lbs, maybe another half pound for the parallel-bridging cables. The Interstate 151R page doesn't list its weight, but I'm seeing values from 19-23 lbs. from other manufacturers. First-page results say 26-30 lbs. for a standard 51R battery. The XS 51R-sized D5100R tips the scales at over 43 lbs without terminal posts.

Price: List price for an XP750 is $120 US, so $240 for the pair. MTP-151R is $225, MT-51R is $210, and D5100R is by far the most expensive at $340.

Conclusion: Dual XP750s result in the weight of a 51R, with the electrical performance of a 151R, at a higher price than either of the flooded batteries, in a bulkier package which adds the inconvenience of fabricating a mounting solution, as well as interconnect cables.

 

There's no need to replace anything but the plastic tray itself. The steel supports remain in place. You get a battery tray for a 2015-2017 Fit with 51R battery. It looks like this:

Bottom-ish view


I believe otherwise. Note that I said "retap", not "tap". "Chasing" is retapping.

You said:
"Engaging and disengaging the flywheel" isn't the domain of battery voltage, regardless of temperature. It's the domain of the solenoid and Bendix.

OK. I was concerned not so much about low temperatures but about high temperatures. It gets awfully hot in there. No sign of UV degradation in the white battery shells?

It's always good to talk these things out, is it not? I mean... that's why we're here at a forum.

 

Chasing is using a tap to remove debris (corrosion included) from the threads. The tap engages and follows the threads, it doesn't cut new ones.

UVA black-body emission starts above about 2700° Celsius. If stuff in your engine bay is getting that hot, your car has more important issues that need addressing.