I am installing a car audio system very soon and I am purchasing items as I go. When it came to adding another battery due to the wattage of the system that I am installing I forgot how they should be wired. I have done this before and since I dont have the batteries in front of me at the moment I thought that I would post this. In other words should they be wired in series or parallel and what is the real purpose of the isolator in a dual battery system.
#1 by Pitbull2 on October 9, 2009 - 8:04 am
Running a second battery is never a good idea as it’s
just an added strain on the alternator. A cap is only
good so far as the audio system isn’t trying to pull
too much from the electrical system.
I know a cap can be beneficial as I’m running one and
I measured a definite change in my electrical systems
response curve to big bass hits with an oscilloscope,
however, this won’t be the case for ALL vehicles.
If your total system power is more than 1000 watts RMS
you will need to:
1. Upgrade the alternator to a high output alternator
2. Upgrade to a heavy duty deep cycle battery
3. Upgrade the “Big 3″ – that is to replace the power wire between the battery and alternator, the ground from the battery to the chassis and the ground strap from the engine/tranny to the chassis with at least 1/0 AWG wire.
Failure to do this will result in you replacing them
anyway as the alternator will eventually fail.
Here is a guide that will calculate what size
alternator and power wires you needhttp://www.datafilehost.com/download.php…
You’ll need Microsft Excel to use it.
See my site for more info http://spkrbox1.spaces.live.com
#2 by sparky34 on October 9, 2009 - 8:14 am
these days you dont need extra batterys, look into the dry cell type, handle high current with eaze and recharge very fast. not cheap but they are doin me a great job
#3 by outg426 on October 9, 2009 - 9:05 am
They should be wired in paralell +,+ and -,- for you to recieve 12 volts. The isolator is so that you can isolate your starting battery from your audio battery. your battery is used to start your car and when your car is running your alternator takes over. so you don’t want to drain your car battery you can drain your back up battery so your car will still start even though your system has been thumping away.
#4 by wizarddr on October 9, 2009 - 9:30 am
Your power problems can be easily solved w/ a cap. A good rule of thumb is 1 farad per 1000w. This will work much better and be more reliable than a second battery. If you still want to use another batt. an isolator will keep the system form discharging the engine batt. This is a good idea if you use your stereo w/ the engine off. You may need a higher amp alternator to keep up w/ the power demands of the stereo system. Reguardless, don’t wire two in series. You will burn up everything there. (24v.)
#5 by wzzrd on October 9, 2009 - 10:27 am
upgrade your alt 160-200amp is fine and use a good deep cycle batt such as optima,deka,or stinger and good cap rated a little over your peak watts of your amps even though you wont run full gain its nice to have the reserve but dual batteries are not needed..good luck
#6 by dawgpoun on October 9, 2009 - 10:57 am
definately in parallel if you wire them in series you’ll end up with 24 volts
#7 by bill on October 9, 2009 - 11:20 am
A friend of mine has 4 Memphis M3 15″ subs and a 1600 watt competiton amp and all he really did that was special was replace the wire coming from the alternator to the battery with 0 guage wire. It allows more current to flow, and you don’t need an isolator. I am planning on doing the same thing for my car. and an isolator causes less stress on the alternator because with an isolator, it is like a distribution block in which the alternator charges 2 different batteries because they are hooked up seperately, instead of 2 batteries on one length of wire (if you just ran the second battery off of the first one directly)
hope this helps, i tried, haha
good luck!