Batteries will almost always show around 12v even if drained, unless they have a bad cell. Once you put a load on them the voltage will drop, but just sitting disconnected they will nearly always show 12v on a meter.
The relatively small size of these batteries leaves little room for error when starting. A car battery has so much reserve charge that they can start a car even if heavily discharged. ATV batteries don't have that much reserve so need to well maintained.
The relatively small size of these batteries leaves little room for error when starting. A car battery has so much reserve charge that they can start a car even if heavily discharged. ATV batteries don't have that much reserve so need to well maintained.