What battery is everyone using

Try this. The AGM battery in my motorcycle was completely dead because someone left the key on (hmmmmm). I put a Battery Tender on it several times but it wouldn't take a charge. I decided that the battery was just dead and that it needed to be replaced so I pulled it out. Before going to the battery store and raising hell because I paid TWICE as much for a battery that lasted HALF as long I tried one more trick. I hooked the dead battery to a jump box (battery) and then hooked the trickle charger up to both. Within 24 hours both batteries were fully charged and the bike battery has been working great all summer. When they're dead they need to see some sort of voltage before the charger will kick on. The other battery provides this.