Running stereo off aux battery?

[Daniel.]

Hi gents,

question to anyone with knowledge in dual battery setups, would it be wise to wire up my new 1600W stereo to the aux battery or should I just run it off the cranking battery?

Only reason i'm wondering is because I know deep cycles like low constant amps where as (if my math is correct) the amplifier will be pulling 133Ah which is pretty high for a deep cycle isn't it? But then if I wire it off the cranker I run the risk of accidentally draining it and also shortening it's lifespan and CCA, right?

Another reason I thought to run it off the aux is because say I pull up at a powered camp site or something, I can plug my deep cycle charger up to the battery and run a fridge and other things including the stereo off the charger and never have to worry about starting the car to get a charge up.

 

[jimmy_jay89]

all high end car systems think sound comp.. run off aux batteries charged by car and wall chargers

some comps require that the vehicle be able to drive on and off

 

[glc]

1600w is a lot of power, your system won't be drawing 1600w constantly. Have you just summed your amplifier ratings? Are they the true power ratings of your amps? Or are they some BS manufacturer fairy dust ratings?

Also, your charger won't be able to power 1600w + other gear.

Easiest way to see what the real power draw of your system will be is to measure the amps when it's running, then make a call on the battery selection from there.

 

[Old.Tony]

It's probably the RMS of the system, so it will actually peak higher but won't peak higher all the time. Using that figure as a reasonable maximum (because you have to have it turned all the way up to reach it and just how deaf do you want to be today) most deep cycles won't last an hour.

With a 1600W sound system I'd guess most times you'd be bloody lucky to be pumping a quarter of that out in actual sound. You use a high wattage system to produce crisper, clearer sound at a lower volume - your average car stereo with 4x50W speakers sounds like crap when it's delivering 200W of sound, but a 1600W system at an 8th of its actual capacity puts out the same amount of sound as the average stereo but it's so, so clear.

So let's assume he's not trying to bounce his eyeballs out onto his cheeks and make his eardrums meet in the middle of his skull and his average power consumption is going to be (say) 400W - that's about 30A and is (just) manageable by the alternator.

 

[bods]

The way I've done mine is running the head unit off the car wiring as normal but then the amp runs off the isolated aux battery. That way you can still use the stereo as normal but only the amp is drawing off the other battery... Obviously that could still be a problem and you could rewire the whole thing so it only draws off the aux battery if you really wanted to