I was thinking of putting a pig tail on my battery to make it easy to charge. I have several maintenance type chargers, plug in and solar. When I was looking at the pig tails I noticed that they are different polarities. The plug in battery tenders don't care about polarity, they identify it and act accordingly, but the solar are specific positive and negative. Anybody know why the positive and negative orientation is not standard for solar panels and battery tenders? I ruined a mower battery by using a battery tender pig tail with a solar charger, it reversed polarity.