Mike Marlow asked me: "Hmmmmmm.... you've got my curiosity up Tom.
Admitedly, I have not gone out and looked at my wife's '04 Sonata to see
what kind of battery it uses, but precisely what is it about your battery
that makes it so difficult to find a replacement?"......
I can only suggest that you do what I did. I went to the battery section of
a few stores, and looked through the fitment guide for a suitable
replacement for my make, model and year.
Usually these books are pretty generous, giving you anything that would fit
under your hood, work with the connection terminals and be considered at
least somewhat suitable, whether it was an exact match or not.
For example, I had a Dodge Intrepid a few years ago that had a listing of
four different acceptable battery size no's. You multiply that by the
number of different batteries the suppliers have in each size (a 72-month,
an 84-month, etc.) and you had quite a selection to choose from.
But when I go to the '02 Hyundai Elantra, it shows the original battery no.
and the original CCA. But then, for any suitable replacement, it just gives
a page wide of dashes, meaning none of the replacements work, and
undoubtedly because of size issues and more. And the original battery is
such an unusual number (anything but a 65 or 34/78, or 35 or 75 or 24) that
most battery suppliers won't have that size unless they can order it.
As I said, Sears DieHard has one in their "International" section, which
both makes sense and is very telling. The battery is also very expensive.
Many other places have nothing.
So I suggest, now that it is Fall, that you spend a few minutes checking out
the battery fitment guide for your car in a few auto parts stores and
battery suppliers. I have no idea what you will find for your car, but at
least you won't be flying blind when and if your battery does go dead.
Hope this helps.