Second Battery For 200w AMP?

[brsox88]

I have been doing a lot of reading about batteries and amps but I am still just as confused. Should I install a second battery for a 200w rms amp (KAC-M3004) if I have any hope of getting 1-2 hours of play time out it at 50% volume? And if I do, would you recommend I hook the batteries up together or separate so that the amp runs off one battery that I would need to recharge on land, or is there a better method? And would it be bad to add a new battery to the current 2 year old battery?

 

[bruceb58]

You will easily get 1-2 hours of playtime. Just because you are running at 50% volume with a 200W amp means you are using 100W. I would be surprised if you are pulling an average of 5A. Measure it to be sure...that's an easy task,

If you run a second battery, always run it separate and get a battery switch.

 

[brsox88]

This is probably a silly question, but how can I check what the actual draw of amps is from my amplifier?

 

[GA_Boater]

Tag on the back or the instructions should have that. Or this from Kenwood, which says 22 amps and that varies on the output or volume - http://www.kenwood.com/usa/car/marine/kac-m3004/spec.html

 

[brsox88]

Thanks, but is there a way to check how much amps my amplifier is using when its on and at 50% volume - that way I can get a better idea?

And is my math right in that if it does draw 5A then I will theoretically get 15 hours of run time on a 75ah battery?

 

[bruceb58]

Thanks, but is there a way to check how much amps my amplifier is using when its on and at 50% volume - that way I can get a better idea?

And is my math right in that if it does draw 5A then I will theoretically get 15 hours of run time on a 75ah battery?

Buy a multimeter that measures current. They usually measure up to 10A. Connect it in series with the amp and turn ithe amp on and slowly watch the current as you turn up the volume. If you go over 10A, you will blow the fuse in the meter.

with a 75AH battery, you really only want to discharge half of that. You never want to discharge a deep discharge battery past 50%.

The rating of the amp will only list the max current. It won't list what the output is at various volume levels. That totally depends on what type of music you are playing and what type of speakers you have.

How is the amp rated for 200W? Is that driving 2ohm, 4 ohm or 8 ohm speakers?

 

[brsox88]

It's driving 4 speakers at 4ohm each. So I can take my multimeter negative and put it on the positive terminal of my battery and the multimeter pos and put it on the red pos cable leading to my amp and that would work?