Largest battery that will fit in the stock tray?

[Hatsuwr]

Might be a bit controversial, but I haven't been very impressed with the higher end batteries I've tried (Odyssey Extreme most recently).

Maybe it's bad luck, but I've seen more cost-effective benefit just increasing battery size.

The tray, on the LX at least, is ~11.875" x ~6.75" flat, with a chamfer ending at ~12.0625" x 6.9375".

The stock battery seems to have been a 27_, which depending on the suffix may or may not fit. Additionally, there seems to be some variance between the BCI spec and the actual dimensions of a battery of a given size. The Deka Intimidator, for example, is a Group 48 but only 6.875" wide. A small difference from the 6.9375" spec, but it should make it fit a bit more comfortably in the tray without sitting on the chamfer. A commonly used size seems to be 34R.

Here's a chart showing some of the best candidates I could find:

And here's a table showing the same sizes with estimates of their popularity (shading on the size, red least common, blue most, data isn't solid though). Oversize dimensions are shaded in red, marginal dimensions in orange.

Below is a graph of Walmart's EverStart batteries available in the above sizes. Color designates the model line, size designates the volume of the battery. Performance is just the averaged percentages of the max CCA and RC. The listings were a little inconsistent, so there's probably an error or two. As expected, increasing size tends to give free or cheap increases in performance (with some exceptions).

Don't put much value in the Marine entries. Those used an estimated conversion from MCA to CCA.

Here's CCA and RC individually:

 

[Hatsuwr]

Actually, Interstate publishes much better data for their batteries. Here are the same charts for them:

 

[Hatsuwr]

I suppose I answered my question, except with some of the marginal sizes where the actual products don't quite match up with the BCI spec.

That MT-27 looks nice, too bad the terminals are swapped!

Here are some of the better (>650 CCA) Interstate options <$300 that have the correct terminal orientation, plus the Deka I mentioned earlier for comparison:

Keep in mind, 'performance' is relative to what is plotted on the graph. So a 0.9 on this chart will not be the same as a 0.9 on the other two performance charts.

 

[gurdy07]

I did the same comparison last year. Basically I ended up deciding to stick with the 27F. If I was going to spend the money to swap terminals, then I might as well get the slee tray and terminals and get a 31.

 

[Hatsuwr]

I did the same comparison last year. Basically I ended up deciding to stick with the 27F. If I was going to spend the money to swap terminals, then I might as well get the slee tray and terminals and get a 31.

Which model 27F did you get that fits in the tray? Most of the ones I am finding seem to be too long.

 

[gurdy07]

Which model 27F did you get that fits in the tray? Most of the ones I am finding seem to be too long.

I got the Optima Yellow AGM 27F. It fits fine, its got a bit of room on each side of the tray.

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[Aracobuilt]

Just last month I installed an Interstate 27f sealed lead acid battery from Costco. It fits perfect and was an upgrade fron the previous Interstate 24f battery. This one seems of a better quality and has a folding handle that sits flush on top, very nice clean look.

 

[Hatsuwr]

I got the Optima Yellow AGM 27F. It fits fine, its got a bit of room on each side of the tray.

Just last month I installed an Interstate 27f sealed lead acid battery from Costco. It fits perfect and was an upgrade fron the previous Interstate 24f battery. This one seems of a better quality and has a folding handle that sits flush on top, very nice clean look.

Ok seeing the 12"+ advertised lengths made me go and compare 4 of my batteries' base dimensions to what is specified by the manufacturer. All of them are shorter by 0.25"-0.75". I thought maybe then the specified length is at the longest area, but those were over or under depending on the battery.

I guess I'll add in the 27_ to the comparison and just ignore the size issue until I see them in person. Makes online only options a bit difficult though.

*edit*
Stopped by Autozone and Advance Auto today. The 27F Duralast Gold is listed as 12.06" and the DieHard Silver at 12.5". Both measured just under 11.75" at the base though.

 

[Mike NXP]

I'm not sure what all of those dots mean, but I'm pretty sure a 27F is the biggest size that will fit the stock setup and hold down. Mine is seen below with Northstar X2 930CCA battery

I bought this battery in 2017 and replaced it in 2023 just for the hell of it. It was still in working order and is now in my shed as backup power when needed and I've since bought another one of the same model with these upgraded terminals ( slee ) another worthy investment if you are adding accessories

 

[PIP]

If there's a way to fit a group 31, do that. Group 31 fits 80 series battery trays fine with very minor trim.

Group 31 is twice the battery of a Group 24 or 27.

In my experience, a Group 31 will outcrank a pair of Group 24's or 27's in diesel applications. One big battery works better than two little ones.

 

[Dirt J]

I couldn't find a 31 I liked locally when I need one, so went with an AGM H8. Close-ish specs to a 31 IIRC. Less than $200 at Walmart. 4 year full replacement.

Sat it on a small block of wood to make up for shorter height.

 

[hoser]

Might be a bit controversial, but I haven't been very impressed with the higher end batteries I've tried (Odyssey Extreme most recently).

Curious to know what is lacking with a standard lead acid 27F battery for you? It does well at starting the vehicle. Are you trying to run all your accessories off the main battery?

 

[Hatsuwr]

Curious to know what is lacking with a standard lead acid 27F battery for you? It does well at starting the vehicle. Are you trying to run all your accessories off the main battery?

Oh I don't have any problem with the 27F, that's probably what I'll end up getting. Mine just came with a 24F from the previous owner. Since I didn't have a 27F on hand, it seemed (at the time) based on just the listed dimensions that a 27F might not fit in the tray I have. That's what sparked me looking into what would fit with the stock tray.