An easy way to add 12 Volt Electrical
Power to smallsize boat
In the three years I've owned Piglet I have never once sailed her at night. Hey, I'm doing good to sail her safely in the daytime! However, I am in the process of adding navigation lights just in case I should be caught some evening far from the dock.
I have owned my West Wight Potter 15 sailboat Piglet for about three years. Some people, like my lovely wife, believe the little boat actually owns me. Be that as it may. Piglet and I decided the other day that she needed a 12-volt power supply to run a depth gauge and a cellphone.
Self Help info - "How to Make"
The usual method would be for me to buy a 12-volt, deepcycle marine battery and install it somewhere in the sailboat. Tens of thousands of boats are thus equipped, and there is certainly nothing wrong with this approach. However, most of my sailing is done where diere are no docks with elearical outlets available to recharge batteries. This is not a problem if the boat is trailered home each day as I normally do. Yet, when I camp for a week or more in lakeside campgrounds, carrying a heavy marine battery to and from a campsite to recharge it can get old fast. In addition to their weight, deep cycle batteries are costly and require a high-capacity charger.
An automobile jumpstarter battery unit was my solution to Piglet;s lack of electrical power. No doubt you've seen these in automobile stores, or advertised during winter months. Several different companies make them, and in general they look very similar-a small, self-contained colored plastic case with two jumper cable clamps, one red and one black, ex- tending from the sides. Their advertised purpose is to start an automobile when its battery is too weak to do the job. In addition to the rwo starring cables, the jumpsrarcer has a 12-volt cigarette lighter socket, an on/off switch, a battery capacity meter or LED lights, a charging jack, and in some cases a trouble light and a 12-volt air compressor. They also come wirh a small charger to recharge the unir s battery. The internal battery can be a scaled lead battery or an absorbed glass mat (AGM) battery. Capacities range from 7 amps to 17 amps. Prices can vary from $20,00 for rhc small lead battery units when on sale, to $70.00 or more for a marine unit. I decided to buy mine from Wal-Mart for two reasons: Their 7-amp unit, the Everstart 300, is very small and weighs only 9 pounds, plus it is equipped with an AGM battery. I've found Wal-Mart's rerurn policy very fair, and Wal-Marts axe like dandelions-they're everywhere!
I first envisioned taking power from die two starting clamps with an elaborate electrical panel with switches and fuses. However. I quickly realised that the 12-volt cigarette lighter would work just great for my needs. All i wanted was ro provide power to my Hummingbird Fishiinder that I used for a depth gauge, and to keep my cellphone charged.
A jumpsrarrer unit is small enough to fit almost anywhere, but it is nor totally waterproof so it should be placed in a fairly dry area. My Potter 15 has a small storage compartment in the floor on the starboard side of the cabin. There I placed a battery box lined with foam padding and die jumpstarter unit inside. I cut the old storage-compartment lid so that it would help hold the battery box in place. While I was curling madly away wirh the saw, I also cut a round hole to hold my fire extinguisher.
I bought an automobile-type 12-volt extension cord with a male plug on one end and socker on the other. With the plug inserted in the jumpstarters 12-volt socket. I measured and cut the extension cord so it would reach the simple plas- tic fuse box I had installed for my fishfinder.
I then attached the remaining female socket end to the bracket that holds my fishfinder's swing arm to serve as a power source tor my cellphone. Since die Everstart 300 has an automobile-type fuse holder built into the circuit, the fuse box I installed would not have been necessary if I had not wanted ail auxiliary 12- volt socket for my cellphone.
The Everstart 300 jumpstarter unit has three LED lights to show irs state charge. A low-charge red light, a mediumcharge green light, and a high-cliarge green light. In addition, a red/green light shows when the battery is being charged or the switch is in rhe on position. My actual on-water experience shows I can operate both
die fishfinder and cellphone for 8 ro 10 hours before the green high-charge light goes out and the medium ligln comes on, showing the battery is 50% discharged. At that point the 7-amp battery shows a charge of around 12.06 ro 12.10 volts. In the three years I've owned Piglet, I have never once sailed her at night. Hey, I'm doing good to sail her safely in the day time! However, I am in the process of adding navigation lights just in case I should he caught some evening far from the dock. Now. as you know, navigation lights consume many more amps of battery' power than a fish finder and a cellphone.
Therefore, if I thought I would be sailing often at night, a larger deep-cycle marine battery would no doubt be a better choice than a small 7-amp jumpstarter-or perhaps one of the 17-amp units.
Since I don't plan on sailing often at night, I believed my 7-amp jumpstarter unit s electrical system would provide me with enough 12-volt power for my limited nighttime needs. However, just to he safe, I thought it would be wise ro run some tests to see how long I could use the navigation lights before the battery was drained. I am installing the traditional bicolor navigation light on the bow of my P-15, and a horizontal-mounted white light on the stern. These 2 lights have one bulb each and consume a total of 1.6 amps per hour. I set up a simple test stand to measure their actual consumption.
I discovered during two separate tests, the 7-amp jump- starter would power the two navigation lights for about 135- minutes (2.25-hours) before the battery charge dropped to 12.10 volts (50% of capacity). At that point the two lights were still bright and I believe they could have been safely operated for at least 30 to 45 minutes longer. However, letting a battery charge drop below 40% of capacity (11.96 volts) can lead to premature failure of its cells. The Everstart 300 has provided me with the 12-volt power I wanted and has met all my expectations very well. The light weight of the unit allows me to easily remove it from the boat. Someday I might actually need it to start an automobile.
It will also be easy to carry to and from the boat for recharging at a distant campsite.The small charging jack is easy to use and, unlike a larger battery charger, ir is not necessary that the charger cables be attached to the battery posts. The only thing I dislike about the unit is the time it takes to recharge if it is discharged to the 50% level. The small battery charger included with the jumpstarter has an ourpur of only 300 mA at 13.8 volts, and takes 8 to 10 hours to fully recharge the battery to 13.10 volts. A small 5 or 10-amp solar panel would work great to help keep my jumpstarter unit charged on those longer voyages when no electrical power is available to recharge the unit. Perhaps that should be my next project? SCA
How to Using a Multimeter - diagnosing electrical system problems