Smallest possible second battery?

[R055]

Hey guys, I was thinking about upgrading my stereo but don't have enough room for concealing a second big battery. I would like a small second battery that would give me about 2 hours of listening without having the boat on. Is it possible to get 2 hours of music on one of those batteries(about 1/3 the size of a full battery).

I plan on making a system with 4 speakers(50-75 rms each) and an 8 inch sub. The 2 hours I need the music won't be loud music, I only need it loud when auctally underway on the boat.

 

[Scott Danforth]

Are you running an amp to power the sub? If so, the 2 hours may be a standard group 24 battery

 

[R055]

Are you running an amp to power the sub? If so, the 2 hours may be a standard group 24 battery

An amp would be the only way for powering 4 speakers plus a sub, right?

Although I think I saw a setup a guy had that he can turn the amp off on a switch and the sound still passes through just not amplified, is that a thing? I wouldn't need the amp when not underway.

 

[bruceb58]

So...what makes you think you need a separate amp? Do you really think you will be running the stereo while you are underway?

Also, if you do want it underway and you needed more volume, the size of the battery is kinda mute since your alternator will be supplying all the power for the stereo.

 

[H20Rat]

Put in a single larger main battery... You could even consider a deep cycle as the main, and yes, deep cycles work well as starting batteries, they just lack the cold cranking amps of a normal batt. That normally isn't too much of a problem in a boat, you aren't out much in -20 weather!

 

[R055]

So...what makes you think you need a separate amp? Do you really think you will be running the stereo while you are underway?

Also, if you do want it underway and you needed more volume, the size of the battery is kinda mute since your alternator will be supplying all the power for the stereo.

Yes I do like running the stereo underway if I'm not teaching someone how to wakeboard and the person knows what they're doing. I just wanted a second small one so my main doesn't die if I'm just listening to music at the dock.

I guess I'll get the new system first and see how it works out with my one main battery.

 

[hz293]

I actually use one of the self contained battery chargers that are also an air pump. Good to have for restarting boat if your battery is too low. I use it to power my electric boat winch so I don't have to run long wires to my car batteries. And it's good if your tires are low.

 

[bruceb58]

The amount of current draw for a given volume won't be that much different with an external amp vs using the stereos' internal amp.

 

[MH Hawker]

i use one of the 4 speaker stereos that has a 200 watt amp built in, and one battery, a group 32 and don't have any problems

 

[gm280]

If you had a better idea of the total current you would need, then we could recommend a matched battery system. If you are not drawing too much current, you could even use some Lithium type batteries to power things and recharge after the fact. Just something to think about.

 

[R055]

i use one of the 4 speaker stereos that has a 200 watt amp built in, and one battery, a group 32 and don't have any problems

Is your system loud enough with the internal amp? Can you connect a small sub to it?

 

[R055]

Thanks for the suggestions guys, I think I'll buy the head unit and speakers first and see how the sound is and go from there.

The head unit I was looking at had 4 channels at 22rms and 50 watt peak per channel.