|
updated by-monthly, from the pages of the Pemaquid Marine Newsletter...
Are your boat's batteries Adequate?
Fact one: batteries - even good quality batteries - do not like to be discharged flat; it drastically shortens their life. Fact two: any time charging times are limited (as is typically the case on a sailboat) it is difficult to fully recharge a battery.
These facts yield two critical parameters for designing a DC system for "house" use on boats. First, the batteries should not be discharged below 50 percent of their capacity; and second, it should be assumed that in normal use they will not be recharged beyond 80 percent of nominal battery capacity available for regular use.
This capacity must be adequate to handle the boat's DC load. To find out what this load is, it is necessary to list the current draw of all the DC appliances on board, multiply this draw by the number of hours of use of each appliance between battery charges, and then add the results to derive a total amp-hour drain on batteries between charges. This should be no more then 30 percent of the rated amp-hour capacity of the boat's batteries. (the rated capacity will be found on the label on the batteries, or in the manufacturer's specifications.)
If your batteries fail to meet this standard, you risk shortening their life dramatically, or having them fail all together. As so often happens, that failure is likely to come when you need them the most.
© Stockbridge Communications, Inc. 800-639-1754
Past Tips
|
