My definition of comfort does involve a higher than normal collection of electronic toys. Even with some toys, the entire energy budget for my Com-Pac 19 was met with the output of a 40 watt solar panel (about 11 amp hours per day in the Mid West). I expect to do something similar with any vessel I purchase.

Energy Budget

I’ll back into this for now by limiting the amount electrical power to whatever I can get from two 60 watt solar panels and store in 4 golf cart batteries. Once my plans become firmer, I can create a more realistic design. At this point, I can only make some crude estimates. The two panels will create about 30 amp hours per day in central mid western waters and significantly more in southern waters.

My storage capacity will be about 440 amp hours. Due to the chemistry of a lead acid battery, I can routinely expect to recharge to 90% of capacity and deplete to about 40% of capacity without damage to the batteries. This means I have a reserve of 220 amp hours for use during cloudy weather and to use when I need more than what I can generate during one day. Of course, if the boat is idle for a period, I want the battery to be recharged to 100 % of capacity and kept there with a good three stage charge controller so that I have no fear of boiling off all the battery water.

Consumption of Electricity

VHF Radio - 0.25 amps on receive and 5 amps on transmit. I will have the device on for 8 hours per day and talk for less than 5 minutes per day. A total of 2 amp hours per day

Anchor Light - 1 amp for 12 hours per day. A total of 12 amp hours. I will also look at building a simple light sensor to control this unit. That way, I do not need to remember to turn it off as soon as the sun rises. I have heard about a coast guard certified anchor light that uses light emitting diodes. If this becomes available, I will switch immediately since this one light is responsible for such a large portion of my total electrical energy consumption.

Light emitting diode anchor lights are already available but they are not Coast Guard approved since they do not meet the regulations for visibility over a fixed distance. This is also true for other portable anchor light devices.

Running Lights - I doubt that night sailing will be a major activity so I will only allocate for 12 hours per week use of running lights. This means about 6 amp hours per day on average.

Interior electrical lights - 2 amps for 1 hour per day. A total of 2 amp hours.

Laptop Computer - I will use this for my trip log, eMail, and updating this web site while on board. 4 amps for 1 hour per day. A total of 4 amp hours.

Depth Finder - 0.25 amps for 8 hours per day. A total of 2 amp hours.

Autopilot - 0.5 amps for 8 hours per day. A total of 4 amp hours per day.

Bilge Pump - unknown at this time but routine usage should be minimal

Misc Usage - estimate 4 amp hours per day

• Cell Phone - recharge as needed from 12 volt system
• Flashlights - recharge as needed from 12 volt system
• GPS - recharge as needed from 12 volt system
• Other batteries - recharge as needed from 12 volt system
• 140 watt Inverter for occasional use of a 110 volt AC appliance
• Recharge battery for the Video Camera as needed

My total energy budget when at anchor will therefore be 22 amp hours with 36 amp hours used when voyaging under sail. With my battery capacity, I can expect to cover my energy needs for 10 days of heavy clouds on the hook without recharging.

Double A type Small Battery Recharging

I built a Ramsey Electronics kit to rapidly recharge common NiCad batteries directly from the 12 volt house battery. This device more than paid for itself in the Florida trip. I will continue to use this on any boat since it works so well. With this unit, I always have 4 freshly charged batteries available. When completely discharged, a set of four AA batteries is fully recharged in only 2 hours. I have configured this system for regular capacity batteries but it is easy to configure for up to 8 cells and also to use the high capacity NiCad or NiMH batteries.

Don’t leave home with out it! In fact, take it along on car trips as well if you have battery operated devices that could require recharging. The only adjustment I have made is make sure that all my battery operated devices use the AA size of battery to minimize the number of types of NiCad batteries I need to keep on hand.

Small Battery Update (July 2001):

After some testing, I've now switched from NiCad batteries completely to NiMH batteries in the double "A" size.  I've also aded a Radio Shack fast charger to my invertory (Model # 23-034).  The reason for the switch was to get better battery life and eliminate the memory effect that is so much of a problem with NiCad batteries.

I still have the Ramsey charger aboard but it is a backup device.  The Radio Shack will do everything the Ramsey does since it operates directly off the 12 volt house battery.  The Radio Shack charger is also easier to use since it will handle either two or four batteries while the kit was set up to require four batteries every time.

Cabin Lighting

I want to use minimal electrical energy for interior lighting. Therefore, interior cabin lighting will be provided by oil lamps when possible. This covers he issue of falling asleep when reading and wasting electricity. I will use the cabin lights only if I need lights for a few minutes   Good oil lamps are getting to be tough to find.   The marine catalogs carry them and another source is the Lehman Catalog and Web Site which specializes in non-electric appliances for the Amish community.

I will also consider task lighting using light emitting diodes. These high output devices are just starting to come on the market in a blue-white output configuration. High brightness devices in a red or orange configuration are already available at your nearest Radio Shack and I will install some of these as necessary to use for interior night lighting so as not to interfere with my night vision. Their power consumption is minimal for the amount of light they put out. I can build them in any physical configuration needed to suit the cabin layout. These lights are also good in that they do not emit radio frequency noise like fluorescent lights.

Air Circulation

I expect to use passive air circulation but some forced air might be beneficial at times. For spot circulation, a simple computer fan that operates at 12 volts and is available at any radio shack is the best choice. These fans are cheap, small, energy efficient, and quiet.

Another item to add to the list is a solar powered active vent. This may not be a cost effective item since I will already have significant solar power available. A small vent fan running on the existing battery bank may be much better. This also means that I can install a three position switch to turn the unit off or reverse the air flow direction as needed. Fans of the type I would consider are available at Radio Shack and draw a mere 0.13 amps.

Other methods of recharge

If I purchase a boat with a diesel inboard, it will also have an onboard alternator so that I can produce about 30 amps per hour into a discharged battery bank.  If I purchase a boat with an outboard, it may have a small optional alternator that can produce about 4 amps per hour into a discharged battery bank.  I may also consider building a small hand or foot operated generator capable of producing 3 to 4 amps. Not only will this produce some useful electricity, but with an hour or so activity each day, it will also serve as good exercise when confined to the boat for longer periods.

Monitoring the battery bank is simple - all I really need is a digital voltmeter. The fancy devices that attempt to monitor the amp hours delivered and removed from the battery bank will not be a substantial benefit to me. My concern is what is the current system voltage and I can get this information from a $15 digital volt meter rather than spending $200 for a fancy device.