Wing Nuts Be Gone!
If you've read any of my earlier posts you may be getting the idea that I'm kind of a nut for details. I am, and details can make the difference between trouble-free boating or a never ending string of "surprises". Its your choice as to which way you prefer to go. Relative to battery installations I see several common mistakes being made today that will definately contribute to the surprise factor, and often when you least expect it. In the photo below you see a fairly typical example of a brand new boat with at least three things wrong with the battery installation. First, the green and red wing nuts that secure the positive and negative battery cables to their posts are no longer compliant with ABYC's E-10 battery standard. The Standard now states that cables 6 AWG and larger shall not be attached with wing nuts. The obvious question is why? This has been common practice for years. Its also caused some problems for years. The cables you see are probably 2 AWG in size, which is much larger than 6 AWG. This means they are intended to carry large amounts of current (amperage) to facilitate engine cranking, maybe to supply an inverter, or perhaps both. The issue is that these terminations may get a bit warm from time to time and repeated heating and cooling cycles will eventually cause the wing nuts to get loose, further exasperating the problem of heat generation. Remember the primary by-product of electrical resistance is heat, the primary causes of electrical resistance on boats are loose or corroded connections, or wire too small for the task at hand. In any event, when these wing nuts get loose enough, arcing can occur at the terminal and if the batteries happen to be connected to a charging source and gassing a bit, the batteries could explode. Or, in a more mundane situation, the engine won't start or electrical equipment could simply just start blinking out. These terminals should be secured with conventional hex nuts and lock washers and tightened with a socket or wrench! Wing nuts be gone! Unfortunately my eye also sees several other matters of concern with the installation above. If you look carefully at the terminal clamps you'll see some light green grease smeared over the terminals. This is to help prevent corrosion from building up and again, some people have been using grease for this purpose for years. Its a bad choice. Remember these terminals will get warm from time to time and the grease will melt and turn to an oily fluid. It will act like penetrating oil and seep between the clamp and the post on the batteries. This in itself will cause electrical resistance and heat, which in turn will cause the thin film of grease to get hot enough to actually dry out, leaving a terrific insulating barrier between the clamp and the post on the battery, which in turn creates even more electrical resistance. Don't use grease for this purpose! I use a product that's readily available at most marine supply stores, Boeshield T-9. As the name implies it was actually invented by Boeing Aircraft. It's a great corrosion inhibitor and it dries to an almost clear film that will not break down with the typical heat associated with battery terminals. Next, as I look at the photo above I see that the batteries are sitting in a wooden enclosure. Standards dictate that battery enclosures be made of materials that will not be affected by exposure to battery electrolyte. Wood will be dramatically damaged by exposure to electrolyte. The easiest fix here is to remove the batteries and paint the inside of the area with some West System epoxy. The epoxy will not be affected by exposure to any electrolyte spill. Now if you are using AGM or gel batteries I would not worry too much about this as electrolyte spills are a non issue. Finally, as I look at the photo, I can't tell for sure, but it appears the only thing holding the batteries in place in the vertical plane is gravity. Not good! Here's what I tell technicians I train. Ask yourself this question, if the boat does a 360 degree roll-over will the batteries be in the same place they were before the event? Yes / No . If you circled yes, the installation is good to go.
If you've read any of my earlier posts you may be getting the idea that I'm kind of a nut for details. I am, and details can make the difference between trouble-free boating or a never ending string of "surprises". Its your choice as to which way you prefer to go.
Relative to battery installations I see several common mistakes being made today that will definately contribute to the surprise factor, and often when you least expect it.
In the photo below you see a fairly typical example of a brand new boat with at least three things wrong with the battery installation.
First, the green and red wing nuts that secure the positive and negative battery cables to their posts are no longer compliant with ABYC's E-10 battery standard. The Standard now states that cables 6 AWG and larger shall not be attached with wing nuts. The obvious question is why? This has been common practice for years. Its also caused some problems for years. The cables you see are probably 2 AWG in size, which is much larger than 6 AWG. This means they are intended to carry large amounts of current (amperage) to facilitate engine cranking, maybe to supply an inverter, or perhaps both. The issue is that these terminations may get a bit warm from time to time and repeated heating and cooling cycles will eventually cause the wing nuts to get loose, further exasperating the problem of heat generation.
Remember the primary by-product of electrical resistance is heat, the primary causes of electrical resistance on boats are loose or corroded connections, or wire too small for the task at hand. In any event, when these wing nuts get loose enough, arcing can occur at the terminal and if the batteries happen to be connected to a charging source and gassing a bit, the batteries could explode. Or, in a more mundane situation, the engine won't start or electrical equipment could simply just start blinking out. These terminals should be secured with conventional hex nuts and lock washers and tightened with a socket or wrench! Wing nuts be gone!
Unfortunately my eye also sees several other matters of concern with the installation above. If you look carefully at the terminal clamps you'll see some light green grease smeared over the terminals. This is to help prevent corrosion from building up and again, some people have been using grease for this purpose for years. Its a bad choice. Remember these terminals will get warm from time to time and the grease will melt and turn to an oily fluid. It will act like penetrating oil and seep between the clamp and the post on the batteries. This in itself will cause electrical resistance and heat, which in turn will cause the thin film of grease to get hot enough to actually dry out, leaving a terrific insulating barrier between the clamp and the post on the battery, which in turn creates even more electrical resistance. Don't use grease for this purpose! I use a product that's readily available at most marine supply stores, Boeshield T-9. As the name implies it was actually invented by Boeing Aircraft. It's a great corrosion inhibitor and it dries to an almost clear film that will not break down with the typical heat associated with battery terminals.
Next, as I look at the photo above I see that the batteries are sitting in a wooden enclosure. Standards dictate that battery enclosures be made of materials that will not be affected by exposure to battery electrolyte. Wood will be dramatically damaged by exposure to electrolyte. The easiest fix here is to remove the batteries and paint the inside of the area with some West System epoxy. The epoxy will not be affected by exposure to any electrolyte spill. Now if you are using AGM or gel batteries I would not worry too much about this as electrolyte spills are a non issue.
Finally, as I look at the photo, I can't tell for sure, but it appears the only thing holding the batteries in place in the vertical plane is gravity. Not good! Here's what I tell technicians I train. Ask yourself this question, if the boat does a 360 degree roll-over will the batteries be in the same place they were before the event? Yes / No . If you circled yes, the installation is good to go.
