Help with power

[Haibane]

I am looking into getting a second battery to run my car audio off of. I was wondering what was the cheapest way to go and how do you wire them?

[sr20de4evr]

well you will want a deep cycle and something that doesn't give off fumes, the first that comes to mind is the Optima yellowtop. Obviously this isn't the cheapest but it is very effective. Just find any deep cycle that doesn't give off fumes (or if it does then you will want to have it sealed off from the cabin so it can vent outside the car). To wire it you will ground it to the chassis and wire a 1/0 ga wire connecting the + posts of both batteries.

[PaulD]

if it's for audio only, you want to seperate the primary and secondary batteries using a relay or an isolator. That way, when the car is off the stereo won't drain the primary battery. If you're thinking it's gonna help you're power with the car on, think again - it will only be an additional load on your alternator.

[Haibane]

So what is the best for when the car is on?

[sr20de4evr]

are you having any problems right now with your battery?
We kind of need to know what the issue is first

and adding a 2nd battery would add some load onto your system, but not much. If the 2nd battery was dead then yes it would add a good bit of load on the alternator, but if both were full then it wouldn't make any difference. And on hard or long bass beats a 2nd battery could help keep your voltage high so it doesn't sink down to 12v or so.

[Haibane]

There isn't any real problem aside from dimming lights and I plan on putting about 1700 or more watts out at continuous from my amps. So I want to be sure that when I get all my stuff in I have the right amount of power. Sometimes the car has trouble starting on the first crank and lights dim, but aside from that. I am only at 300 watts continuous right now to my 2 subs

[Diesel2NR]

I'm acutally having the same problem with just 200 watts of MTX. I've learned to turn off my head unit and other electrical equipment (IE: head lights, cause subaru will shut'em off for you but as soon as you go to start up again they're on, and climate control stuff) before I shut the car off. It usually starts really easy. I am having problems with my headlights dimming when the speakers hit. Noticed it really well tonight when I was out and really needed the light cause of the rain. I'm going to find an Optima Battery dealer around here and put one in and hope it helps for now. I'm going to use a capacitor when my actual system (700RMS on subs then) and hope that solves the problem...If not, I don't know what I'll do.

[sr20de4evr]

wow you guys have some problems, your lights should not be dimming and your battery should not be draining on only 2-300 watts. I mean at 300 watts and 12v you're only pulling a max of 50 amps from your electrical system. Even with every electrical component on in your car and a tiny stock alternator you shouldn't be draining anything. If you get dimming then upgrade your batt to chassis and engine to chassis grounds. If your battery is draining and you're having problems starting go to Autozone or a similar store and have them test your alternator.

Just for reference, I'm pushing about 1200rms with no cap, stock battery and stock 80 amp alternator and I get very very slight dimming in the interior lights, and no problems starting even after driving for hours with the system blaring.

[Haibane]

I have very slight dimming in interior lights, and also only have it when the doors are open, I rarely have trouble starting the car, so I guess nothing is really wrong

[chicago_guy]

ok i gotta a question...do u think id b fine runnin 1800 watts rms off a 100 amp alternator? or wud i hafta get a cap? i think its almost proportional to sr20de4evr's setup.

[sr20de4evr]

With 1800 watts you're pulling a max of 275 amps at full draw. This rarely happens and chances are you'll be pulling closer to 100-150 with it cranked. Mix this in with the gaps between songs or quiet points in songs and you should be fine, just don't go around blaring test tones 24/7

[chicago_guy]

but how else am i gonna piss of all my neighbors? lol...aight thats a big help...and it saves me a good $100 or more

[PaulD]

caps help with some cars, they don't with others - it's best to try one out first if you can. The only thing that really delivers power when the car is on is the alternator - if you don't have enough power, you need a bigger alternator. A second battery can help keep the voltage from dropping too low, but at a price of robbing power during non-musical peak times (to recharge it). Not a very good compromise if you ask me

[chicago_guy]

i doubt i can jus try out a cap, id have to go out n buy one...like i sed earlier my alternator is 100 amps...do u kno of ne companies that make a larger alternator for a 2001 chevy blazer? or rather a 4.3 liter V6 262 SFI. if u dont kno of ne then shud i jus upgrade to a deep cycle battery n limit my playing time?

ps-i kno i keep askin a lot of questions, i jus dont want to screw nethin up on my car or my system. so i realli appreciate all the help.

[Diesel2NR]

the Subaru Legacy Alternator is 85 amps I believe. I'm hopin this capacitor will work, because if not, I'm going to be screwed I guess.