ArticlesVoltmeter Installation and Running Lights Modification
by Erik Van Renselaar [esvanr@sbcglobal.net]
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On most Catalina Capri 18s, the battery is the only electrical power source. Most outboard motors in the 2 to 5 hp range (which seems to be the size most appropriate for the C-18), don't have charging capability and solar panels that have the wattage to keep a C-18's battery charged during times of frequent use are in the over $300 range. My battery management routine consists of charging the battery once a month and after every sailing trip. So far, my sailing has been mainly day trips, so the battery doesn't get used too much (the fishfinder/depthfinder is the principal current draw). The battery is a Group 24 marine/RV deep cycle lead-acid type rated at 85 amp/hours. The charger I've been using is the Guest model 2606, 6 amp three-stage charger. It's a very compact unit and it seems to do a good job of adequately charging the battery. I usually leave the unit on for over 24 hours to allow it to 'float charge' the battery for awhile, which is the third stage where the battery gets its "topping-off" charge.
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To monitor the battery, I installed a Blue Sea Systems #8003 voltmeter. The original unit I installed measured the 8 to 16 volt range in 0.2 volt increments, but this did not tell me much about a battery that was not wired in to an onboard charging system. The next type that I installed (and currently use) is the Blue Sea Systems #8004, State-of-Charge voltmeter. It has a scale of 11 to 14 volts in 0.1 volt graduations and has a secondary scale that indicates the percentage of charge for both flooded cell (lead-acid) and gel cell batteries. This tells me much more about the battery, as just a few tenths of a volt in a stand-alone 12-volt battery can mean the difference between a 50% and an 80% charge state. Unfortunately, Blue Sea Systems has discontinued the production of this meter and they have no replacement for it. Some marine supply vendors may still have the item in stock, so you might want to check around. A possible low-cost alternative could be an automotive-type panel mount digital voltmeter. In an automotive application, I have used the Nordskog brand, 2 1/16in. diameter digital voltmeter available through Summit Racing
(www.summitracing.com). It is available in green or red display, reads in 0.1 volt increments, and costs approximately $40. The meter appears to be well constructed and has a scale of 6 to 18 volts. It could fit into the same location where my Blue Sea Systems meter is installed. Note: The new version of the Blue Sea Systems voltmeter #8003 has a secondary scale for the 11.7 to 12.8 volt range in a smaller arc and also has a percent-of-charge scale. I'm not sure if it is as accurate in the small range as the discontinued #8004.
The installation of the meter was fairly simple. A cutout template was provided with the unit to help in accurately positioning the holes. A 2" hole saw was used to make the hole in the 3/8" thick bulkhead. The meter was installed just to the lower left (when facing it) of the electrical switch panel. I chose that particular location as it was close to the switch panel and easily viewed, but not cluttering the main area of the bulkhead. The meter is wired into the battery (+) lead, just after the panel mounted 20-amp circuit breaker. I used an inline fuse holder in the power lead. It contains a 1-amp AGC glass fuse. I also used the same type fuse holder for the fishfinder/depthfinder power feed. For a bit more refined installation, a small fuse block with 3 or 4 fuse positions could be installed in place of the inline holders. The two holders are in locations that are easy to access and inspect, so that upgrade is not currently a priority for me. A power switch for the meter was mounted in the main switch panel. I located some nearly identical (to the original) black plastic rocker switches at a local electronics/computer parts store. The are of the SPST type. The store's part number is . I don't know if that number will help in finding a similar switch, but if you take an example (from the switch panel) to a good parts store, they should be able to closely match it. The original and aftermarket switches accept the small, 3/16" wide push-on female connectors. These can be found at most electronics supply stores and Radio Shack. The switch was labeled using one of those popular label printers available at most large office supply stores.
If you notice in the panel/meter picture, there is another rocker switch installed next to the running light switch. I installed that and wired it as the "Steaming/Sail" switch. This solved a problem with the way the running lights were originally wired. The problem was that the mast-mounted steaming light was not wired separately from the white stern running light. Thus, the lighting configuration was always in "steaming" mode when turned on. I didn't feel that this was a responsible (or legal) way to operate at night while under sail, so I changed it. Now, the "Running" switch powers the new switch, called "Steaming/Sail". When the Running switch is turned on, the stern light is powered. When the new switch is in the Steaming position, the masthead light is on. When switched to the Sail position, the masthead light is turned off. The bi-color bow light is still controlled by its separate switch.
You may also note in the photos that I installed a "cigarette lighter" type of 12-volt power outlet below the meter. It is wired directly after the main circuit breaker and is unswitched. It's a Radio Shack item and is rated at 10 amps. It has worked well during the few times I've used it, but a marine version from one of the numerous marine supply vendors might be better if used frequently in a saltwater environment. As my boat is stored at my house and not sailed very often in saltwater, I believe the outlet will work just fine (it has so far). I find the battery meter and power outlet to be very useful devices. The secondary switch for the running lights is a refinement that is easy to do and in my opinion, worth the effort.