Originally Posted by seb5thman
Hello All, I am the new owner of an '86 Cal 22 and hope to get some advice on a problem with my lights. The boat has a single marine deep cycle battery (2-years old) that runs all the lights (running, cabin, mast, etc.). The problem is that the nav lights go dim very quickly, after 20-minutes or less, even with a fully charged battery. I assume the 8-hp Mercury outboard is re-charging the battery, but I don't know for sure. When I'm sailing at dusk or after hours I have to run the engine in neutral to keep the lights charged.
Any ideas??? I don't think it's the battery, but will get it checked. I have a solar panel to recharge, but I'm not sure thats working either. Where do I start? Any advice to a new owner is appreciated.
First of all, on a twentysomething-year-old boat the problem could be just about anything. That being said, I would start by checking the electrolyte level in the battery, and cleaning the battery terminals and all the other "main" electrical connections, including the ground connections (wire brush the corrosion off of everything down to shiny metal, and then reconnect everything nice and tight). These are the easiest fixes and are two of the most common problems. Next, get a cheap multimeter and check the voltage across the battery terminals while the engine is running at least half speed; if it isn't at least 13.5V, then your alternator, or voltage regulator, may be kaput (this probably isn't the problem, since your lights are bright with the motor running; but, if it is, you'll probably have to take the motor to a mechanic to get either of those fixed). If you have done all that, and you still have problems, take the battery out and have it load tested at an auto parts store. If it fails, get a new dual-purpose marine battery, not a regular car battery.
When you get it working, consider installing a second battery (a deep-cycle one) to act as your "house" bank. To do the job properly you should probably get yourself a book on small boat electric systems (The 12-volt Bible for Boats is a good cheap place to start). It isn't all that difficult, but having a reference will help you to avoid most of the major pitfalls. And, whether you add a second battery or not, you will almost certainly do yourself a favor by straightening up the wiring (which always seems to be a mess on older boats) and (as much as possible) cleaning any corrosion you find associated with the electrical system.