I had better clarify some stuff. First, the Dekas we have had experience with--all bad--were the Deka deep-cycle variety. The hyd pumps on the dump trailer (farm use) are battery powered--the Deka's started fizzing after ? 3 months. We switched to the largest size Delco Voyager deep cycle and have not had any fizzing ("gassing") or failures yet.
I learned about batteries from my dad, an electrical enginneer. He was worse than me as far as telling you way more than you thought you needed to know. And he was, uh, rather absurd about trying to nurse old batteries for their maximum life--he finally quit that after his first 68 years. I don't expect an 84 month battery to serve me for 84 months--I buy it because they usually have a 3-year full replacement guarantee instead of 1-yr, and they have a greater CCA and "reserve capacity" than the 48 or 60 month batteries. Most any battery you buy will have more than enough juice, even in zero degree weather, when the battery is brand new. The batteries CCA and reserve begin to decline almost as soon as the acid is added. The 84 month batteries still have enough juice at 65%, but the 60 month batteries won't.
I figure that any battery past 5 years is in the "bonus" period. As long as it serves me well, I'll keep using it. But at the first hint of any slow cranking after 5 yr., out it comes. I might stick in something less critical, use it to power my 12v diesel fuel pump, or something like that.
It used to be I'd keep a nearly dead battery, and just park on a hill (do y'all have hills where you live?). Yes, Atco, we used to drive a truck with a dead battery up onto Windrock. I'd preach on the virtues of a manual-shift vehicle--you would never be stranded because of a dead battery. But I got a surprise with my 1998 GMC 5.7 Vortec 5-speed manual. First, the idiotic and elementray theft deterent systems locks out the ignition--roll it down a hill, turn the key to on and pop the clutch in 4th gear and . . . nothing but the "security" light on the dash. And fuel injection in most new vehicles requires an electric fuel pump to pre-pressurize the injection system. The times they is a changing. Even modern dirt bikes have electric fuel pumps and FI now, though some will start without a battery (I think they have capacitors.
Anyhow, I don't think you can get your money out of the Optimas. Buy the best "$ 100" battery you can, and figure on replacing it sometime after 5 yr. The last $ 20 of battery life can be mighty inconvenient to squeeze out of 'em, and maybe the most expensive $ 20 you try to save.
Now, ATCO, like I said the other day, what kind of pathetic folks stay up late and "talk" this stuff? Maybe when I come to Knoxberg to see my shrink, I'll come by and see ya. Reckon you'll recognize me when ya see me?
