Simplest way to add a second battery

(chaser) · (chaser) **Join Date: Sep 2006** 08-11-2007, 2:38 PM

I have just the stock stereo system in my boat: Single amp, 4 speakers and a sub. I want to add a second battery to my boat just for peace of mind. I don't like to run the radio for over a half hour or so when we are just sitting with the boat off for fear of killing the battery. What would be the simplest way to add a second battery that I could Isolate the radio on it when the boat isn't running so I don't drain down the cranking battery at all. It would be nice if the alternator could still charge up both batteries when we are running too. Although about every third or fourth time out I just throw the battery charger on just to make sure I get a full charge on it. The second battery would also be piece of mind if the cranking battery went bad on me. Thanks.

(firemedic) · (firemedic) **Join Date: Jul 2006** 08-11-2007, 4:35 PM

Put in a perko switch and a second battery, easy...

(nc05lsv) · (nc05lsv) **Join Date: Mar 2005** 08-11-2007, 7:01 PM

for what it sounds like you want, Erick is spot on. You could also look at using a combiner. you could jam to music and kill house battery but never have to worry about the starting battery because they are kept seperate. Cant go wrong either way I just do better with something I don't have to think about as i am apt to forget

(peter_c) · (peter_c) **Join Date: Sep 2001** 08-11-2007, 11:44 PM

Stinger relay or the equivalent. Rig it off the ignition so every time the key is on the batteries are combined. With the key off separated. If you want to be able to keep them completely separated add a switch inline to the ignition switch.

How much simpler can it get...and still have isolation?

malibu_nut 08-13-2007, 12:47 PM

i'm with peter on the relay idea. that way you never have to remember to swicth batteries. when the boat runs it will recharge the second battery. better make sure it's a deep cycle though.

(kenteck) · (kenteck) **Join Date: Jan 2005** 08-13-2007, 1:02 PM

These relays work great, or you can use an isolator, small voltage drop but not much to notice unless you have a big system, battery switches work good, but you have to switch them manually, here is a link for some different ideas:

http://www.ase-supply.com/Sure_Power_Isolators_kits_s/20.htm

(kenteck) · (kenteck) **Join Date: Jan 2005** 08-13-2007, 1:11 PM

simple

(hatepain) · (hatepain) **Join Date: Aug 2006** 08-13-2007, 8:21 PM

I just hooked 2 of them together + to + - to -

(goodwin) · (goodwin) **Join Date: Feb 2006** 08-13-2007, 8:25 PM

Hate N Pain, do you have Optima Blue tops?

(olskooltige) · (olskooltige) **Join Date: Mar 2007** 08-14-2007, 12:05 PM

Battery combiner is the easiest and most noise free. Isolators seem to introduce noise for most.

(acurtis_ttu) · (acurtis_ttu) **Join Date: May 2004** 08-14-2007, 1:15 PM

How does an isolator induce noise?

(hatepain) · (hatepain) **Join Date: Aug 2006** 08-14-2007, 10:37 PM

Brown, Hey what's up? I have Exide blue tops. There the same thing and cost the same so go with whatever is more accessable to you. I got mine at Schucks for like $180 and come with a free replacement for 18 months.