Can someone give a concise discussion of batteries? What is "deep cycle", group? Cranking amps? Dual cycle? Starting battery? I am a weekend cruising Bene 381 and I have to replace a heavy, large battery just forward of the engine. This original battery has been in for 9 seasons including winters and is the first time I am replacing, so it doesn't owe me anything. I'm on a mooring and use my batteries to start the engine a few times a week, I run the engine about 15min off and on the mooring. Ocassionally longer. I would like to replace it with something a little lighter and cheaper, can I trust my local Wallmart?
12v Batteries
- Thread starter prosmile
- Start date
So you don't have ANY other electrical loads except the starter??? Sorry for all the questions but gota have it to advise you correctly.
Do you anchor out overnight? (anchor light, cabin lights, fans, etc)
Do you sail at night? (nav lights, cabin lights, instruments)
Do you have GPS, Autopilot, wind and speed instruments?
What are your sailing habits (day sail, weekend warrior, etc)
I'm finding it hard to believe a 38' boat would have no other electrical loads beyond starting the engine unless it was a motorboat (which it clearly is not)
Do you anchor out overnight? (anchor light, cabin lights, fans, etc)
Do you sail at night? (nav lights, cabin lights, instruments)
Do you have GPS, Autopilot, wind and speed instruments?
What are your sailing habits (day sail, weekend warrior, etc)
I'm finding it hard to believe a 38' boat would have no other electrical loads beyond starting the engine unless it was a motorboat (which it clearly is not)
http://www.westmarine.com/webapp/wc...10001&page=Selecting-a-Marine-Storage-Battery
You can read the rest of the West Marine Advisors online or in their catalogs - very helpful information, assuming you don't want to read a book about electrical systems or do more internet searching.
You can read the rest of the West Marine Advisors online or in their catalogs - very helpful information, assuming you don't want to read a book about electrical systems or do more internet searching.
Load details
No other charging, just engine. Instruments yes, wind, radio,depth, gps. Radar rarely. No electric anchor. Nav lights occasionally.
If you are running "house loads" then you'll want a deep cycle battery. Deep cycle batteries are designed to take deeper discharges and have more cycle life and will run your equipment longer than the same size battery in a "starter". The Kirkland's from Costco, the Energizer's from Sam's Club or the Maxx series deep cycles from Wal*Mart will all work.
Alternatively NAPA sells the SAME Deka battery that West Marine does only for about $80.00 - $100.00 less. You want the one marked Deep Cycle though.
For starting your engine you can use a "dual purpose", deep cycle or a "starting battery" provided it meets your engine manufacturers minimum cranking amp needs..
Group size is nothing more than the case size of the battery itself. The most common groups used in marine batteries are Groups 24, 27, 29/31, 4D & 8D and for 6V batteries the GC2 size. As the case gets bigger so does capacity. Group 24 is small and they go up from there.
A deep cycle battery will start you motor too. consider for a moment that when the wife fires up the 1000W hair dryer and runs it for 5 minutes that is 1000/120= 8.3 amps on the AC side and 83 amps on the 12 DC side. Most starter motors don't draw that much juice and certainly not for 5 minutes. A deep cycle will hold up fine for starting your motor.
Precisely why I have never had a "dual purpose" or starting battery on any of our boats even for the reserve/start battery. Start batteries are less expensive though, so if that is all it would ever be used for you could save a few bucks, but hardly worth it IMO.
You got a big boat, so get a nice pair of group 31s. Anything over 4-5 years needs replacing. Also, you might want to run that diesel a little longer than fifteen minutes at a time