Polarization matters in more than Sunglasses

By Pete Lane

It’s said that the last Presidential election polarized the country, but if so then I’m pretty sure there’s a lot of debate over just whose side is positive and whose is negative. If there was as much disagreement in science, I suppose that half of the magnetic compasses would point toward the South Pole. Fortunately, there are no journalists questioning the laws of physics.

Perhaps that’s because testing those laws can be expensive or painful. Once children learn the meaning of “hot” through experience, they aren’t likely to challenge its reliability. Likewise, the concept of gravity sticks with them after a few scrapes from falls or broken toys. But when it comes to electricity, many people never experience anything more memorable than dire warnings of its power.

That’s fortunate because when it comes to home electrical current a first encounter could prove fatal. But the alkaline batteries that motorized toys and electronic games use don’t produce enough current to make an impression, except perhaps by testing a 9-volt with one’s tongue. A flashlight may work regardless of which way the end of the batteries point, as long as they point the same direction. If they’re installed wrong, the only immediate evidence is that it doesn’t work.

But the toys that big boys use take bigger batteries, and the consequences of mixing up polarity can be damaging or painful. For instance, riding mowers use small automotive-style batteries, and at a casual glance, there’s no difference between the positive and negative terminals. Sometimes the positive terminal has a red ring around it, or at least a red cap over the terminal before it’s installed.

However, replacement batteries may not have their terminals in the same position as the originals, so it’s important to look closely on the battery shell and find the plus stamped near one terminal and the minus by the other. The red wire always goes to the positive terminal and the black on the negative.

Just a few weeks ago my friend was preparing to install a battery into his SeaDoo and decided to see how the battery in his mower was hooked up. When he looked there he saw that the red wire was going to the negative side of the battery, or at least that’s what he told me as he was about to connect the SeaDoo battery.

That didn’t sound right, so I looked at the mower and saw that he was looking at the plus and minus signs on the battery hold-down bracket, not the battery itself. The bracket was original equipment, but the battery was a replacement with terminals at opposite ends. Had he continued and reversed the connection on the SeaDoo he would at the very least blown a fuse, and a spark in close proximity to a fuel tank is never good.

If I looked good that day, it’s in part because of a “learning experience” of my own a few weeks earlier. When I reinstalled the battery in my pontoon boat I accidentally reversed the battery connections. It was sort of dark when I did it so the spark that jumped when I completed the connection sort of clued me that things were not good.

The silence when I turned the key convinced me that I’d really screwed up. However, a quick call to a mechanic told me where to find fuses on the engine, and sure enough one had blown. Luckily it was an automotive-style mini fuse and had a pack of spares for my car. I was lucky in that instance…but the fuses in mowers may not match those of your car, so be careful when it’s time to hook up a battery.