Pardon me but the entire subject can be confusing as hell. Let me explain why.
Let's exaggerate for perspective...
A 2.75% antimony battery from a manufacturer and another 2.75% antimony battery from the same manufacturer. One has plates the surface area size of a quarter and are 1/8" thick.
The second has identically -constructed- plates, but their size is that of a billboard and are a foot thick.
If the same plate construction AND the same plate paste are used in both batteries, guess what, the batteries are going to get along fine.
Some OEM's use thicker plates on some models. And can cram FEWER stacks in each cell. Fewer stacks = less surface area and I'll leave it to others to state the performance reaction. Let's leave cycle life count out of this for now.
A consumer reacts to R/C A/H and CCA without regard to the relationship of weight of an accumulator and stack thickness.
Job one is to find out for sure the antimony alloy percentage. Plate and pasting techniques should be limited to a single OEM, got it? No Johnson Controls mixed with US battery if you want a reasonable match.
But antimonial percentage content differences are the kiss of death as far as "battery matching is concerned". Most new breed batteries seem to use 1.280 weight acid so this is less of a concern than it used to be. Acid densities must match.
I do not know of any OEM that plays musical chairs with plate and paste composition in their run-of-the-mill various car jar cyclable batteries.
So determining the manufacturing origin of that OEM battery would be high on the list. Matching it to a sister battery regardless of capacity would serve it's purpose. Only OEM knows for sure construction details. But by factoring BCI group size, cell PLATE COUNT, CCA, and weight, there is a very high chance of finding a match to the OEM battery.
Since the existing battery is almost "new".
A telephone call to the manufacturer and not to anyone else would be required. In this case an APPLICATIONS ENGINEER would suffice to provide information accurate enough to rely on.
Then determine which re-brands are the same battery.
15 minutes on the telephone should do it.
Hope this helps.
