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I have a mazda 323, with a large (about 950)cca battery under the hood. I was hoping to add two deep cycle batteries as well (back near my amp rack) and was wondering what would happen if I did not use any type of isolator or relay or any other device of the sort. Would the batteries not charge evenly? Would they possibly drain eachother? any suggestions on the subject would be great. thanks.
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Well, bad idea to use deep cycle batteries in a car. They just aren't built to be partially discharged and fully recharged. I dont think anyone will agree with me on that though. Why 2 extra batteries?? Without knowing anything about your system, it's tough to say if you even NEED a second battery. Do you plan on key off listening?? Like sitting in a parking lot for hours cranking you system? If so, then yes, a couple of batteries will give you that ability, however, if you get extra batteries, you MUST isolate them from the main car battery using an isolator, or a large relay. Also, when your engine starts, and those batteries are pretty dead, they become another load on the alternator. Now, lets say you've been cranking the sys with the engine off, those batteries are pretty dead, and you start the engine, and continue bumping for another hour, at full crank. Your batteries probably wont charge, because, while your engine was running trying to charge those batteries, you were cranking, taking all the available power to run the system. Now your back at the same place you were, 2 dead batteries and you cant crank your system for a while. See the point? In car audio, the SMALLER the battery, the better. Once your engine is running IT runs the system. I dont believe, in reality, unless your running the system key off for extended periods of time, that you ever need a secondary battery in a car, they just present more problems. But, that's just me.
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STILL waiting to hear a GOOD pair of HLCD's!!
Use your ears to judge components, NOT your wallet! K.I.S.S.
posted
I guess I need more info to give my full opinion on this. If you already have an aftermarket alternator and are looking to add more batteries to help stabilize your voltage under relatively short bursts (not an hour of cruising) then I would say adding a battery is not a major concern. Audiophyle makes some valid points with it adding additional load to the alternator when the battery is discharged. Therefore, I would probably not recommend an extra battery to a stock alternator for extended period use. However, if you compete and are looking to help hold the voltage more stable, I have seen increases of over a dB by adding an extra battery. Common sense must be exercised if this route is taken. Playing with the engine off or playing hard for extended periods of time will overtax a standard factory alternator. I hope this helps some.
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Team Thunder Member John Hellemn ------------------------
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Well lets see if I can give a little more info. Right now I am using a PPI PC 21400 on my subs (12 10w0s, soon to be 12 10w3s). Also, once summer starts, I will be using a USamps VLX 400, which is obviously going to "tax" my electrical system (more like butt-rape it). I will be burping it for competitions, and I know that just one battery will not be enough. The extra batteries will be mostly for SPL bursts. I am hopefully going to upgrade the alternator soon as well, but for now, adding batteries seemed the best dollar per dollar fix for when I burp it.
posted
I would recommend the additional batteries then. I would also recommend either an isolator or a solenoid in your case also. I myself am partial to solenoids. Do a little research on both and see which you think would better fit your application. Hope this helps.
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Team Thunder Member John Hellemn ------------------------
posted
Ok, can you guys give me a thorough explanation of both isolators and solenoids, and what each one physically does? Are these things that i really need, or is it only if i want to be playing my system with the car off for extended periods. Thanks.
posted
Also, I am confused as to why you say deep cycle batteries would be a bad idea for car audio. If im not mistaken, the most popular battery around (optima yellow top) Is in fact deep cycle. It seems that deep cycles would be the perfect choice for someone who wants to play their car with the system off, or a lot of other situations. Any help here? thanks.
Isolator is a box with a bunch of resistors, diodes, and other junk we wont mention. If one of these parts "dies" (which they commonly will), the unit will still work. The only thing with this though, is that you will not be passing full voltage. Ex: 1 diode goes out, you will drop .5 volts. Still works, just not well.
Go find your local Stinger or Streetwires deale. Ask for a Stinger SR200 relay. This is a simple relay used to pass and isolate current at 200 amps continuous and 600 amps peak. We sell them at our shop for about $50. Fool proof and CANNOT die.
About deep cycle batteries. They are NOT made for car audio use. Or even car use. Read the warrant card on ANY Optima battery. It CLEARLY states that they are not made for "non-starting" applications.
Deep cycle batteries are made for trolling motors on fishing boats. They are designed to be discharged slowly and recharged slowly. They even have special chargers for these things. Simple as that.
Why are they used and seen in car audio applications? Optima saw a huge success in theier "red top" series (overrated anyways). Well, they had to come up with something new. I mean, how many times can you be featured in "New Machines" in CA&E? So they just made a deep-cycle battery version of the red-top. Of course people will buy them....they are "new", and "pretty". I think I am straying off the topic, so back to what I was saying...lol
1. Match your batteries. It doesnt matter what they are (not deep-cycle, we already covered that), they can even be Wal-Mart specials, as long as they match.
2. Try to get a bigger alternator. No sense having a bunch of batteries if ya cant charge them?...right?
3. FUSE....I can't stress this enough....FUSE wherever a power wire goes through a body panel.
posted
Ya i agree with all of the above mentioned information, however you also may want to add a capacitor or two to provide your stereo with voltage during peaks of music playback.
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