Adding a third battery ...diagram?

[mytime]

Does anyone have a diagram on how to add a third battery to an existing two battery bank? I have an idea on how to do it but would like a second opinion.

My existing set up is (standard set up) one alternator, battery switch (1-both-2), 2 output battery charger. I did not see a battery combiner anywhere.

If I need to upgrade to a 3 output charger that is fine but would prefer to use my existing charger.

My use for third battery is to dedicate it to a amp and sub-woofer also adding an electric head drawing 20 amps per flush.
However I want the option to switch into existing battery bank if needed for starting in an emergency. Thanks for any input.

 

[woodster]

adding a third battery is a good thing ...parall the first two to make one house bank add the third one for a backup starter battery and charge it with an echo charger or a arc ...i think mainesail has some info on this in his article p base or musing with mainsail ...do a search on here and you will find a lot on the subject then study what you fine ....then you will have more questions i am sure ...post them to get answers ...this bunch is the best when it comes to helping others

 

[Benny17441]

When you parallel two batteries you make them into a single battery, just a larger one. Just choose one of the two batteries you already have and parallel the new one to it. Run a cable from positive terminal to positive terminal and another cable from negative terminal to negative terminal and you are done. Take notice of the position at the switch of the battery you added the new one to, whether #1 or #2, so that one will become your house bank. Don't know what charger you have but most will adjust and direct the charge to the bank that needs it the most. If all your three batteries are deep discharge you could combine them all by placing the switch on "Both". This is not the only way of doing it but you can keep your charger and have the capability to combine them all. Remember the battery switch controls which battery bank will service the loads and which battery bank will receive the charge from the alternator. Go easy with that sound system in crowded anchorage.

 

[Chris Patterson]

I'm trying to understand, do you want to amplify the head sounds to the stereo? Sounds cool, but I would rather hear Ozzy..

 

[Gunni]

second opinion: A 30 ft sailboat does not need 3 battery banks. It needs a really good house battery (and charge system). Out.

 

[mytime]

The Sub woofer is only a small 6" woofer mounted under Nav Station...Not really for blasting the music...But I do enjoy a good action movie with surround sound when we get the down time...