Battery Charging - SailNet Community
LinkBack Thread Tools
post #1 of 1 Old 05-23-2002 Thread Starter
Contributing Authors
Join Date: Jan 2000
Posts: 158
Thanks: 0
Thanked 8 Times in 6 Posts
Rep Power: 16
Battery Charging

My boat is equipped with two deep-cycle batteries and an 11-horsepower diesel with the original alternator. I expect to run the engine only for short periods of less than 30 minutes and my loads will be limited to the autopilot, VHF, stereo, bilge pump, and basic lighting. Can you suggest a best-bet approach to battery charging?

Don Casey responds:
If the boat is tied to a dock, your best bet is an AC battery charger. For a little over $100 at a discount price, you can buy a three-stage charger that will take good care of flooded batteries. If you have gel cells, expect to spend $250 or more.

If the boat is on a mooring in a sunny environment, a small solar panel is the way to go. The output of the panel should be around 0.3 percent of total battery capacity, perhaps a bit higher if your climate is less sunny. In your case, that works out to around 0.6 amps, or about what you would expect from a 10-watt panel. That will feed about 20 amp-hours into your batteries per weekóless when it is cloudy. If that doesn't meet your demands, you can go up to a 20-watt panel (or two 10s) without significant risk of overcharging.

The alternator on your engine will not keep your batteries up with 30 minutes of running time a week, no matter what its rating, and putting a bigger alternator on an 11-horsepower engine is probably not a good idea. Either the panels or the charger will be the least costly, least complicated, and most effective approach for your boat-use pattern. Good luck to you.

Don Casey is offline  
Closed Thread

Quick Reply

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.
Click Here to view those rules.

Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may not post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is Off
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome