I'd just like to know what most people here tend to believe is sufficient when it comes to multiple kilowatts rms or power draw.
I have my own opinions when it comes to this, but I've seen a lot of conflicting information online.

1. How many Amp Hours of batteries do you prefer per 1000watts rms draw of your system?
2. How many Amps of Max Alternator output do you prefer to have per 1000w rms.?

Cheers.

watts/voltage=amps. so Xwatts/14.4=Xamps. the 14.4 changes in certain situations but 14.4 is the most common voltage for amplifiers.

amp hours is really only useful when you've topped out your power production(alternator). if your alternator is producing enough power you wouldn't even have to put a battery in for it to work perfectly.

if you are trying to supplement power shortages with a larger battery then amp hours becomes useful. then its like amp hours/amp draw=how long your battery will last. if you are trying to draw 40 amps on a 40 amp hour battery this means its going to be dead in about and hour.

also many people seem to think adding a second battery will help and overtaxed alternator which is false. each battery adds a amperage load so when you add it on your alternator has to work harder for the same result. so you are better off using 1 good battery if you are trying to get a bit more power out of your electrical system.

the only time adding more batteries is useful is for running without the alternator on and if you have a big enough alternator to charge them all.

Yeah I generally use 13volts to overaccount for any voltage drop then divide by amp efficiency so for a class D amp i'd get about 90Amps draw full tilt with 1000wrms.
My alternator is 85Amps max and my battery is a pile of shit, something like 25Ah so I can't use over 500wrms without the amp cutting out from voltage drop. Suggestions online say 75Ah per kwrms is good to go by with 50Ah being the minimum. My subs are capable of taking 1000wrms and my amp can put out more so right now the biggest that can fit in my engin*** would be 85Ah and I'm working on figuring out if I could try and make room for a 100Ah batt.

Another thing though, would you say using a Deep Cycle battery as the main cranking battery should be fine? Read a lot on the net that says they're made only for low output for long periods of time, but I'm looking for a single battery setup as I agree with a lot of what you posted.

that said engin***... I have no idea why it got censored...

EEEEEEEEEEENNNNNNNNNNGGGGGGGGGIIIIIIIIINNNNNNNNNEEEEEEEEE BBBBBBBBBBAAAAAAAAAYYYYYYY


FUCK

you have to also account for your cars normal power needs. your car generally uses about 50 amps with headlights,blower motor and so on.

so if you even managed to fit a 100AH battery you would still deplete it to unusable levels in about an hour with 1000rms+cars electrical needs. bigger batteries are only time delays they won't fix the problem.


what car are you using? a lot of times you can salvage a 30-40 amp better alternator off another vehicle made by your cars company.

you've done the big 3 upgrade right?

people saying that about deep cycles are silly. current AGM deep cycle technology can do just as much as a non-deep cycle performance wise it just needs to be about 10-20 percent physically larger. for the size trade off you get a battery that last 5 times longer,doesn't lose voltage if you deplete it,can recharge from nothing many times before you do any actual damage.

and ya the world filter is annoying lol. it thinks you are try to say a popular site beginning with E.

well my car is almost 30 years old so it literally has almost no other draw during the day, lights draw power at night, and radiator fan blows every now and then if i'm stationary with the engine running.... it uses a carby too so no electronic fuel injection or fuel pumps.

And tbh an hour or even half an hour would be fantastic, I'm just trying to get rid of the horrible voltage drop I'm getting which is causing my map to go into voltage protect with the engine on.

My stock alternator was 50Amps and I had it rebuilt about a month ago to 85Amps, that's as big as it gets for this car unfortunately. In a couple of years I plan on getting a better car and putting a HO alt on it but for now this'll have to do.

The batteries I'm looking at aren't AGM, this is the biggest that'll fit in my engine ^$%#Y#$%&#$ bay
http://www.allpurposebatteries.com.au/product_info.php?cPath=21&products%5Fid=114

and yes i've done the big 3 upgrade with 2awg wires.

This post was edited by RSDXzec on Aug 4 2012 09:53pm

link doesn't work for me.

remote mount your battery if you run into a space issue. you can put it int he trunk with the subs if you have room.

you sure there isn't an SUV made by your cars company around the same time? they generally get larger alternators than the cars in the same year models.

if it was me i simply wouldn't bother trying to run 1000rms.

you might also consider building a new mount and adding a second alternator.

it's an 84 Holden Astra, it's old as shit lol. Don't think they made SUVs. Spent enough getting the alt upgraded and there isn't room to work with for a second alt (it's also too much trouble for a car I only plan to use for another 2 years MAX), and I think on a decent battery 1000wrms would be the limits of the electrical.

Now I'm not talking about sitting for hours playing heavy bass music, I almost always play with the engine on so afaik with a 75ah batt i should be alright to do so.

Here's the battery screenshotted


I designed my box to use up my WHOLE boot so there's no room in there lol

This post was edited by RSDXzec on Aug 4 2012 10:28pm

even with added battery longevity you will eventually be stranded unable to start your car unless you get battery charger to top it off when its parked.

its going to be unreliable,inconvenient,cost more money than its worth to bother trying to run 1000rms daily.