View Full Version : adding 2nd battery question

03-05-2011, 09:48 PM
Heys guys,

Right now I am running four tower speakers(nvs entitys) off a kicker 750 amp. I am planning on adding two 12" subs and an addition 600 watt amp to the boat this year. I am only using one battery as of right now. Would you recommend adding a second battery? We rarely just sit and use the radio, the boat is usually always running so I didn't know if it was necessary. If I should add a second battery, should I go with a perko switch or is there another product you would recommend? Thanks for the help.

03-05-2011, 10:28 PM
Yes, definitely add a battery. I'd go with Blue Seas. Check this thread for info and pics: http://moomba.com/msgboard/showthread.php?t=9759

03-07-2011, 05:52 PM
If I had a 2000 watt total Class AB amplifier system and I played my system at full output there would be moments that the collective draw of the stereo and boat operations could exceed the alternator's peak output. Certainly this could be the case at lower rpms. So in that scenerio I would add a second battery. Two Group 24s would be sufficient.
If I never played my system at rest then I wouldn't add a switch at all. But, I would want two identical batteries in type, size and age in this application. And, I would probably add a single small maintenance charger like a Ctek 7 amp model for example. You would be putting your boat into storage with very little battery discharge if any. So the charger would be used primarily to offset self-discharge and maximize your battery longevity.
If I played a large system at rest for any length of time then I would add a second battery and add a dual battery switch. Instead, you can add an automatic voltage sensing relay like a SurePower or Blue Sea if you want the fully automatic (set it and forget it) operation. We prefer the SurePower but both are good units. For very short periods, the discharge would be so minimal that you could get by with a basic ignition-triggered solenoid like a PAC rather than a voltage-sensing version and still have the totally automatic operation.
As systems get larger and playtime is longer then the solutions must get more complex. But in your case, it sounds very simple. I would add a second battery and a simple solenoid with a small single bank maintenance charger. Not because its cheap but because that may be all that is required to fit your needs and just a little beyond.

Earmark Marine