2 batteries or 1

Joined
Jul 20, 2004
Messages
74
I just purchased a new 20 foot boat and I have one wet cell battery with an on/off switch. I am taking a portable radio with me due to fear of draining the battery and not being able to restart the engine. I usually like to anchor for up to 3 hours with the radio on and don't know how long I can drain down the battery and still be able to start the engine. I only boat on the lake and do not ever get out of sight of land. Engine is a 5.0L Mercruiser with 260 PHP. Any recommendations from this very experienced board would be appreciated. <br /> <br />1. How long can starter battery be drained with stereo and still retain enough charge to start engine.<br />2. Would it be better to get a quickstart battery box at West Marine for $80/each(recommended by Marina) or install another deep cycle battery with another battery switch which would allow me to switch between batteries?
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: 2 batteries or 1

Carry 2 batteries. It will give you piece of mind... Even a $40.00 dollar car battery will work in a pinch..
 

macshak

Cadet
Joined
Jul 28, 2004
Messages
9
Re: 2 batteries or 1

I would definately carry 2 batteries. Last time I went out I only had 1. Guess what, had to be towed back to dock because of dead battery. Although the battery should have been replace some time ago. I replaced this one, and I plan on getting a second before I go back out. You just never know.
 

TwoBallScrewBall

Lieutenant Commander
Joined
Sep 14, 2003
Messages
1,695
Re: 2 batteries or 1

My vote is for two batteries. Autozone has small marine batts for like $40 or $50. Cheaper than a jump box and more juice.
 
Joined
Jul 20, 2004
Messages
74
Re: 2 batteries or 1

Thanks for the input. I agree with having two batteries, but it appears that I now have two choices:<br /><br />A. Should I also install a switch to only use the second battery when the engine is off.<br /><br />B. Install the second battery but not connect to it. It would only be used as a reserve.<br /><br />Also, should the second battery be a deep cycle battery that would permit recharging. I have heard that the problem with a deep cycle battery is that it may not have the juice to start the engine.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,313
Re: 2 batteries or 1

Get a battery selector switch and a dual purpose battery. The dual purpose will give you the reserve of a Deep cycle amp the amperage required to start the motor
 

MFG197

Petty Officer 1st Class
Joined
Aug 26, 2002
Messages
236
Re: 2 batteries or 1

what dingbat said. it's easy to do .... i did it.
 

Luna Sea

Lieutenant Junior Grade
Joined
May 20, 2002
Messages
1,069
Re: 2 batteries or 1

For 3 hrs. of radio use, the dual purpose is preferred. Strictly deep cycle would be for larger boats using more juice.....
 

ThomWV

Senior Chief Petty Officer
Joined
Dec 19, 2003
Messages
701
Re: 2 batteries or 1

I agree on the dual purpose and there isn't any way in the world that you're going to run down a good medium sized battery (Group 27 or so) with a couple of hours of radio use, tape player maybe, but not a radio.<br /><br />Oh, if I were you and I was still concerned I'd just buy one of those very small motorcycle/riding lawn mower batterys and use it for the radio. Charge it after every three or four uses and it will treat you just fine. I think you can buy them for about twenty five bucks. That and a set of alligator clips and you'll be in business without taking up much room.<br /><br />Thom
 

18rabbit

Captain
Joined
Nov 14, 2003
Messages
3,202
Re: 2 batteries or 1

Two batteries. Thom's idea is excellent...a small battery for the stereo that can be recharged as needed. You can get more sophisticated and install a second deep or dual battery, battery switch, permanent wiring, etc but you don’t need that for your application. I would take Thom’s advice and spend my time on the water. :)
 
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