POWERBOATER’S GUIDE TO ELECTRICAL SYSTEMS 1. Covering the positive battery terminal with a boot or nonconductive shield 2. Installing the battery in a covered battery box 3. Installing the battery in a compartment specially designed only for the battery or batteries In addition, there are a few other rules in the standards with which you should be familiar.
The battery should not be located near fuelsystem components such as lines, filter canisters, or tanks.
Battery-box covers must be ventilated, and the area around the box must be vented to outside air.
All battery boxes and cases must be constructed of nonconductive, noncorroding materials.
Batteries must be secured so that the fasteners cannot come in contact with battery electrolyte.
Everything within 12 inches of the battery must be covered or in some way protected so that it’s completely nonconductive. This is to prevent any accidental short circuit between the item and the battery terminal.
An easy way to satisfy these standards is to install all batteries in a commercially made plastic battery box such as the one shown in figure 5-5. Pre-made battery boxes in a variety of sizes are available at any marine supply store. Just remember to secure the box with the straps provided, and make sure that the battery is well ventilated to outside air.
Battery Maintenance and Testing There are several situations that can cause premature battery failure, but the most common by far is owner neglect. The second most common cause of a battery cashing in its chips before its time is the malfunction of the charging system. However, I classify even this as owner neglect, because the conscientious skipper should monitor this charging system closely enough to catch a malfunction long before it can permanently damage the battery. Other common causes 74
Fig. 5-5. Typical plastic battery box.
of premature battery burial are using the wrong type of battery for a given application, such as a deepcycle battery where a cranking battery is needed and vice versa; and using batteries that are too small for the task at hand. (The information on selecting batteries at the beginning of this chapter should have corrected any problems you may have had in those areas.) And then there are the boatowners who chuck out perfectly good batteries they have convinced themselves are bad. I’ve seen more batteries unnecessarily replaced than any other systems component I can think of. It seems that many otherwise sane people blame the battery for everything from an autopilot that doesn’t work properly to warm beer. They will throw away a healthy battery without a thought to the more probable causes of their troubles. Just because your engine is cranking over slowly or your cabin lights are getting dim doesn’t mean you need a new battery. With the retail price of a small marine battery bouncing around $100, I think it’s worth checking the old one to make sure if you really need to replace it before you discard it. As battery technology and construction methods have improved over the years, maintenance has gotten a lot easier. The biggest problems we used to have were keeping the terminals clean and topping up the cells with distilled water. These tasks are still necessary with the new versions of wet-cell batteries, but the new technologies have greatly reduced the constant need to add water.
