2nd Battery for stereo

What's a decent 2nd battery? All I'm running is one 500 watt amp. I know it's probably not necessary to have a second battery but it gives me piece of mind. I don't want to spend a ton of dough and I don't have to lay it on it's side. For audio does it need to be deep cycle?

You will want a deep cycle or can get by with a Dual purpose battery. I would recommend Deka. They are one of if not the only battery still manufactured in the US and are top quality. They have been consistently underrated from the factory.

What kind of battery do you have for starting?

Also I would put a battery combiner/separator. My company sells a product made by Sure Power which works almost flawlessly. It is super easy to hook up, right around $50 and gives priority to your starting battery so you don't get left high and dry.

http://surepower.com/separator.html

I second the battery serparator/combiner. I got one from Brett when I did my second battery and it was easy to install and serarates/combines the batteries on its own.

I have two DieHard marine deep cycle batteries on a perko switch (definitely recommend that or separator/combiner). The only charging they get is from the alternator while the boat is running and I have never had a problem with them. They are pretty cheap ($100) and my stereo system is ~800W.

http://www.sears.com/shc/s/p_10153_12605_02827524000P?vName=Automotive&cName= Batteries+%26+Chargers&sName=Marine+Batteries

Just a quality brand-name marine deepcycle is all you need, it will serve you well.

Another vote for, at a minimum, a Perko style multi-bank switch.

The problem with the Battery selector is that they are 30-50 dollars. The Surepower 1314 does all the combining and switching for you and I can sell it to a wakeworld member for $52.75. It seperates the batteries when your starting battery gets below 12.5 volts. You don't touch anything.

I went with a Stinger battery isolator:

http://www.hifisoundconnection.com/Shop/Control/Product/fp/vpid/1333954/vpcsid/0/SFV/30046

I don't want to overthink this but I also found this while researching: The most important consideration in buying a deep cycle battery is the Ampere-Hour (AH) or Reserve Capacity (or Reserve Minutes) rating that will meet or exceed your requirements and how much weight you can carry. Most deep cycle batteries are rated in discharge rates of 100 amps, 20 amps, or 8 amps. The higher the discharge, the lower the capacity. Reserve Capacity (RC) is the number of minutes a fully charged battery at 80° F is discharged at 25 amps before the voltage falls below 10.5 volts. To convert Reserve Capacity (RC) to Ampere-Hours at the 25 amp rate, multiple RC by .4167. More ampere-hours (or RC) are better in every case. The battery with higher ampere-hours (or RC) will tend to have longer lives and weigh more because of thicker plates and more lead.

What is the minimum AH you guys recommend?

Brett, isn't Stinger a similar product to Sure Power? I don't want to have to turn a perko switch.

Travis
yes they are similar, sure power has been around since 1959, they are the original battery isolator / separator inventors, you will see a lot of companies producing the same thing as sure power, Brett is correct with using that type of battery and i would also use the battery separator as well, it does not have a voltage drop like an isolator would. that is a great set up for running a dual battery set up....if you want more info about sure power products http://www.ase-supply.com/Sure_Power_Isolators_kits_s/20.htm
also that is a good price that brett has for you, the 1314.

Brett still going out xmas, its getting colder than a bit.h out here...

We'll see what the weather is like.

Travis I'm impressed. You've been doing your homework. BCI technical comittees write the standards for how the batteries are test, and for marine you are correct. It is ran at 25 amps. However, don't confuse RC with the manufactures design. A battery with thick plates (Lifeline) and thin plates (blue top) can have the same capacity. The battery with the thicker plates is better suited for high current.

If you want the best battery (quality and high current) get the Lifeline (Concorde Battery, West Covina, CA). All hand built...they even test the vent caps prior to assembly. Not just a sample, every one.

Brett where can I buy the surepower 1314?

From me. Call 800-234-2981. We are open 7:30-5 pacific time. The other option is to send me an email to the email in my profile.

i can vouch for the SurePower 1314 that Brett is recommending. i bought mine from Brett and had it installed last season with a second battery. no switch/selector. works great.

last boat, i used two optimas, a blue sea 3 way switch and the yandina c100 combiner (up to 90A alternators and ignition proof). that also worked great, but is a little more expensive. little more than twice as much.