So an update. Always wanted to see how the
Odyssey Extreme AGM would do. Dealing with GM's OnStar battery killer has brought this back up for me via a couple of family members toasted batteries.
So family tried an Odyssey Extreme 75-PC1230 in a Hummer H3 that OnStar likes to randomly kill with month long parking times. Think it's OnStar as that appears to be a known-known and the fuse hasn't been located due to far-far away location and other family factors. Not even AZ heat out east where it's at so one factor down. Battery is about 4 months old and it's first overdischarge. Family went to start it after sitting 2 weeks:
"It's Dead, Jim." One Jump start, 20 min drive time, and the next stop the tow truck HD jumper cables couldn't bring it back. ~8.x V and, yeah, a warranty exchange. A battery kill switch (disconnect) will be put in to Overkill Brute Force solve the problem of having to put the H3 on the hook over a dead battery. After hours with places closed, ordering the not as common Extreme version... all lead to use of well funded Roadside Assistance: "Just tow it".
My conclusion is Page 12 in the Odyssey Extreme Manly Manual PDF attached here is Marketing Bull S#it as the test results are NOT repeatable. "a" means ONE New battery. Las Vegas odds for "a" battery to survive a overdischarge. Reality be "house favored odds" that overdischarge on an 'in use' battery will simply stay dead with shorted cells combined with severe sulfation.
At least they can't deny warranty because it's supposed to survive this.
(C) Can the battery recover from deep discharge conditions?
Yes, the ODYSSEY battery can recover from extremely deep discharges as the following test results demonstrate.
(1) German DIN standard test for overdischarge recovery
In this test, a PC925 was discharged over 20 hours (0.05C10rate)2 to 10.20V. After the discharge2 a 5Ω resistor was placed across the battery terminals and the battery kept in storage for 28 days.
At the end of the storage period, the battery was charged at 13.5V for only 48 hours. A second 0.05C10 discharge yielded 97% of rated capacity, indicating that a low rate 48-hour charge after such a deep discharge was insufficient; however, the intent of the test is to determine if the battery is recoverable from extremely deep discharges using only a standby float charger.
A standard automotive charger at 14.4V would have allowed the battery to recover greater than 97% of its capacity. (Really?! You test and show this somewhere?)
These test results prove that ODYSSEY batteries can recover from deep discharge conditions. Reinforcing this conclusion is the next test, which is even harsher than the DIN standard test, because in this test the battery was stored in a discharged state at a temperature of 122°F (50°C).
Anyway even older before GM decided that live cig lighters 100% of the time were costing too much in roadside assistance ... 2002 Yukon. Left GPS plugged in and on. Won't crank dead battery next day and it recovered. Come to find out it's one of the two Optima's that I gave away after exchanging in 2012.
@Will L. I am looking at a made in 2012 Optima Battery that J.C. Optima would consider "A failure of Today's Value Engineering" as it still works.
Yeah, I checked the date code. It has stress cracks at the terminals, but no black leakage signs like the others (out of the 6.5L diesels) I pictured. It only has had the GM terminals used. It's sister battery died (they warranty exchanged it once since 2012 and then lost the receipt I think) with one or more shorted cells in Post #18 on a 454 gas truck from a couple of random drain to overdischarge and little use. (The most miles that 454 gets most years is literally going to the emission test station once a year.) Charged and started now and them, but, not just driven much. One of those an old long bed pickup is useful at times to just have around. Yeah flat spots on inflated tires...
The 2002 Yukon is garaged, light starting load 5.3L gasser, and not driven every day rather 1-3x a week. As other DD gas vehicles have experienced unremarkable short life in this heat with Red Top Optima's I am seeing an "oddball" that has lasted nearly 4x normal 2 year battery life out here. Garaged and not a DD is clearly a big reduction in extreme heat exposure.
