I am good with Harley OE. The important thing is to install a battery tender like TQ has recommended. I get 4-5 years on the average with properly maintaining battery. So much so I plug into Tender after every ride...
+1 on HD OEM, You might also check out DEKA batteries on E-Bay.. Really not that much of a cost difference HD batteries are Great. If you're not near a dealer check option #2.
HD batteries are mfg. by East Penn Co., whose house brand is Deka. I recently bought one from this link. Best price I found anywhere and fast shippiing. Deka Batteries by Part Number
+4 on OEM HD battery. Usually get at least 5 years from HD battery. My bike sits from Nov.-March or April depending on weather. I use the tender to keep it full as well.
My personal experience on interstate battery was 2 years. (On my Kawasaki and didn't have it hooked up to tender. Definately will shorten battery life if not hooked up to tender as well as less work on your bike trying to charge battery).
Best battery is the one that fits your application, has plenty of reserve power, and at the quality level and price that meets your expectations. Fortunately the 1993 model year battery has good battery selection cross reference. The OEM battery is pretty good, uses AGM technology (high density Absorbed Glass Mat) which makes the plates use purer lead for rugged vibration resistant internal plates). They are made in the USA (can't remember the name) but only a handful of battery makers are made in the USA. Naturally they cost more than flooded cell lead-acid "regular" ones. Good luck with your search, just don't base your selection purely on price. :newsmile071: