Battery charging

[Tim22]

I recently acquired a 2006 sun cat that I will be keeping at a mooring. I am considering possible alternatives for keeping the battery charged and am looking at solar, or adding an alternator to the engine. The alternator will require running wiring to the battery compartment. The boat is currently in storage so I can't really investigate this at the moment, but I would welcome any suggestions.

Thanks
Tim

[HideAway]

I ve been using a small flexible solar charger for many years.  I got it from West Marine - I just tie it on top of the boom and try to keep the bird poop off of it.  Every six months or so I charge the battery with a regular automotive charger.  It takes several days of charging sometimes to bring the deep cycle battery up.  I should note we have a very simple electric system - just nav and two seldom used cabin lights, a gps, and fm radio.  My outboard is a self starting engine - meaning I start it myself by pulling the rope.  No alternator on the engine and our self steering device does not use power.

An Important Note:    Before you put the charger on check the water levels in the battery.  They will need filling before you start charging.

I just completed this process a few weeks ago and found the battery did not need a charge.  I should mention we live in FL and store the boat at a marina on a sunny trailer lot.   If I were to do it again I would have purchased a motor with an alternator, but still have the solar charger.

Matt

[tmorgan]

I charge the battery at the beginning of the season to full charge with an automotive charger.  I have a portable solar panel I use to charge it when the sun is out.  We sail on a lake and for that the solar panel keeps the battery charged.  When we go to the Chesapeake Bay for an extended cruise (2 weeks), I generally charge the battery when we are in a transient slip with the charger one time.  We don't use any electrical devices other than lights and iPhones.

[Tim22]

Thanks for the info. The more I think about it the more I think I will try to keep this boat simple (electronically). As I'm sailing at our cottage on a deep inland lake there is really no need for depth sounder, log, vhf etc. That really just leaves lights for the few times we are returning home late in the evening. A small solar panel should do the job - are there any recommendations as to the wattage required.

Tim

[capt_nemo]

Don't have a recommendation on solar panel wattage. Check West Marine Catalog for their advice.

As a previous owner of large sailboats and trawlers with a variety of electronics, electrical energy consumers, and battery concerns, I applaud your decision to keep it SIMPLE.

Today I am a Com-Pac Sun Cat Trailer Sailor who is a die hard "minimalist". I sail my boat in Southwest Florida saltwater and do not have a battery aboard or concerns about charging. The running lights I have, should I ever need them, are inexpensive battery operated flashlight types. My Garmin Handheld GPS is battery powered and used to provide speed and compass headings as well as Lat Lon should I need that function.

Free of the worries associated with all that electrical stuff, I concentrate first on sailing my boat as often as I can, and second, making MEANINGFUL changes to my boat that improve performance, efficiency, and safety.

(P.S. I have a B.S. Degree in Electrical Engineering!)

[cavie]

An alternator on a motor on a sail boat. Give it some real thought and get someone like Nemo to figure how long you would need to run it to replace what ever you used and them remember it is on a sail boat..  Does not compute in my book.

[ontarioSuncat]

When out for a curise for a week or more on my Suncat I did not have any issue with a small battery pack. I only used LED lights and my Garmin 76SCX GPS. My VHF is a hand held unit. A solar panel could keep up to the demand. Last year my wife wanted a Fix VHF and now I find the power hard to keep up if I use the Fixed radio too often. So I am thinking about getting an alternator installed on my 5hp motor. This would help charge the battery. I find that a boat cruise will be composed of about 75:25 sail and motor. Even on a good sail day the motor is run for at least 1 hour getting into an anchorage and setting the anchor and getting out again. Over a three week trip I burn about 20Litres of gas or about 1 litre a day. That works out to 1.5 hours a day running the motor. The more electical members could calculate the current created with a 5 amp alternator.

[Tom Ray]

Last year my wife wanted a Fix VHF and now I find the power hard to keep up if I use the Fixed radio too often.

Most fixed mount VHF's have a low and high power transmit setting, and unless you have some good reason to use the high power one, the lower power setting will use quite a bit less power. Receiving uses very little power compared to transmission, and high powered transmission uses most of all.

Same goes for the handhelds, but they more often need to use their higher power setting.

[ontarioSuncat]

There is a Radio net call in back to Little Current each morning and I need the 25 watts to cover the distance (20 Miles away average). While this last only a few seconds, I noticed if I speak for more than a minute the Standard Horizon show Low voltage warning. We listen on it to the net calls for about an hour each day. Some calls to other boats where the 25 watts are needed. I do try to talk on the lowest power needed. My battery has only 28 amp hour capacity. So I could replace the battery with a real one and that may solve the problem too. If I can do just one thing, upgrade the battery OR get the Alternator I would be happy. We get to a marina once a week so I could charge the battery real good then. The rest of the time the solar charger would add some top up. What do you suggest? I really don't understand the power stuff?