These pictures are to serve as a warning to those people who use the top "wing nut" terminals to carry heavy current. Here's the story:

Last summer, I had decided to go to pair of 6-Volt golf cart batteries to replace one of my 12-volt batteries. The boats' battery terminals were the regular heavy clamp-on type as required; you know the kind that slip over The post and are clamped with a bolt. But when I switched to the pair of golf cart batteries, I needed a wire between batteries. So I installed a piece Of 1/0 gage wire. My mistake was that I used ring type terminals on the cable ends, and secured them to the threaded post on top of the battery using the wing nut provided. I made sure they were "bright and tight" when I installed them. I had no problems last year with this configuration. Although these pictures can speak for themselves, I'll try to elaborate a bit. During my investigation I learned that the ring terminals provided on some marine batteries are to be used to secure light loads (a few amps) such as a bilge pump directly to the battery. But when I connected the sixes together to achieve 12 VDC, I was pulling full engine starting current through the ring terminals on top of the batteries. The threaded top post of the battery has insufficient surface area for heavy current. The result was that as the connection heated up during a start, the lead battery post melted a bit, causing an even worse connection. And each subsequent engine start made the connection worse. It failed the end of July. It was a scary feeling to think that the sparks and hot lead was going on right next to the hydrogen gas given off from the battery caps during an engine start. Battery explosions are high on my list of things to avoid while boating. I was very lucky.

Original Battery Post

Overloaded Battery Post

Submitted by:

Joe Impellizeri

IMPELJR@aol.com