My M1009 groaned when I expected it start- it's been running like a champ. But today it just slowly turned over a piston's worth and that was all. I pulled the front battery cables and the tester said replace. I checked the warranty and purchase date of April 2020, and figured it was time for a new battery, Napa sold me the same one for about $140. Put it in and exactly the same result. I just checked the rear battery- Says replace. I am checking to see if an ancient battery charger will bring the amps up so I can put a newer charger on it. Question is both batteries at once? What happened? did one die and drain the other off as well? which one was the likely culprit?