FWIW, I recently got an XP-10 to jump start dead batteries like the one in my GMC2500 6.0 V8. I charged the XP overnight and hooked it up. NOTHING. Checked all the connections, tried the boost. NOTHING. I had to use my shop charger/starter to get the truck going. I returned the XP and would not trust one in the middle of nowhere much less at home.
I asked this question in a different thread but Odyssey told me these 31m batteries won't charge properly with the standard 95 amp LC alternator. What's been you guy's experience with that. She told be about sulfation and other stuff I didn't quite understand.