Killing batteries please help!!

[Boulevardvette]

I have a 2006 Dodge Magnum and I am on my third starting battery in 3 months. Just got a new battery thru warranty and doubt they will give me another if I fry this one. My system consists of a Pioneer dvd head unit, all speakers replaced with Memphis coaxial's running off of factory amplifier. Sub stage is an Skar EVL 15 powered by a Skar RP1500. Electrical is a 160 amp Carquest alternator (recently replaced) powering a Batteries Plus X2 Power group 94 (made by Northstar) starting battery and a XS Power XP750 wired together powering the amp. Big three is done including 1/0 Sky High CCA from the alternator to the back of the car where the battery is. Car also already has a 2 gauge cable ran from the alt to the battery stock since it's such a long run. I have fried two of the X2 Power batteries somehow but the small XS battery hasn't been affected. Had both failed batteries checked and the voltage would be good but the cca would be so low it wouldn't start the car unless hooked to the xs battery. At full tilt the voltage will drop to around 12.2 and at night the lights will dim slightly. Can't see why my current electrical can't keep up with this small system. Anybody have an idea of what is going on? I have checked and rechecked all connections and grounds and am at a loss for what to do next. I have ran more powerful setups on pretty much stock electrical in other cars and have never had this problem. Sorry for the longwinded post and thanks for any help

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[audiolife 5,000+ posts]

If your voltage is falling to 12.2 volts your alternator is not keeping up for sure and the big three would need to be done as well front to back.

 

[evilmonstertruk Premium Member]

You said you replaced your alt, have you had it tested since then? Also, a AGM upfront and the big 3 should be plenty for 750rms. I have three times that or more and I don't any upgrades on my stock Ford taurus

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[BOOMINGRANDPA 5,000+ posts]

check voltage on batt 30 mins after u get home , then check it in am.. if u lost voltage at nite u have drain somewhere, mine was alt.. u can unhook + wire on alt leave off at nite see if that does it., if so alt is problem..

 

[wew lad 5,000+ posts]

does anything stay on after you turn the vehicle off?

 

[Chris McNeeley]

does anything stay on after you turn the vehicle off?

^^^^^ this. and what is your charging voltage?

 

[audiobaun 5,000+ posts]

Does sound like a bad alternator.I had an issue with a Honda alt doing the same thing and it was getting expensive quickly.It took me a couple alts swapps to figure out it was the alt.i ended up having the alt tested before leaving Orileys(ill name the place of business)I ended up spending an entire Saturday and found that 6 stores all had bad alts and ended up going to Nappa and finally got a good one.

 

[ThxOne Premium Member]

Is there an external voltage regulator added to this setup? If so... it the wire that turns on the regulator getting constant power? Mine was and drained two batteries.