boat battery trickle

bobdog
bobdog Solar Expert Posts: 192 ✭✭
in Solar Beginners Corner #1
My brother has a boat and he would like for me to set up a system for keeping the batteries topped off while it sits in storage. Now I can set him up with a charging system with panels, CC's etc, for fully charging the batteries, but I'm not sure about just a trickle charging system. My question is, can I use a small 5-10 watt panel on a 12 volt battery without a CC and if so, will I run the risk of it over charging the battery? The same for a 24 volt battery bank. They are your standard marine batteries (el cheapo) and I'm guessing here, 115 ah each. What I'm concerned about is leaving just a panel attached without having a CC to regulate it, and thus over charging the battery. Finally, I have one battery bank set up as 24 volt (trolling motor) and I know I can hook up 2 5 watt panels in series to make a 24 volt system, but again without a CC will it over charge the battery bank? Thanks.
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Comments

  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    #2
    Re: boat battery trickle

    short answer, you need a CC.
    I asked a similar Q last year and that was the answer. Battery will overcharge and die sooner or later..
    HTH
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
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    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #3
    Re: boat battery trickle

    i would imagine you are taking the stuff so if there's a breakin that they will be sure to break there n**s on only being able to take the batteries and 1 pv. understandable. also, due to the multivoltages you may employ, try something like this,
    http://www.solar-electric.com/pros15solcha.html
    yes, it will give a thief something more to take, but at least it isn't your more expensive tristar.
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  • 2manytoyz
    2manytoyz Solar Expert Posts: 373 ✭✭✭
    #4
    Re: boat battery trickle

    If you use a 5W panel, it'll never overcharge the battery. Even in full sun, that's less than 1/2 Amp charge. I had such a setup for a year. Full details here: http://2manytoyz.com/solarcharger.html

    The panel simply unsnapped from ladder rail, and unplugged from a wire harness when taking the boat out. This was for a single battery setup. Less than 30 seconds to install or remove the panel.

    Long term such a setup could be an issue if the boat wasn't used. A battery can be trickle charged to death. Over time, battery solution can stratify, leaving part of the plate in acid, the other part in water, resulting in permanent damage to the cells. I did exactly this several years ago with a battery in my garage. A periodic equalization charge will gently stir the solution. A vehicle that periodically moves will also mechanically stir the solution - as in the case of our boat.
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