alternator, battery, or cap

i'm getting different information from each installation person I speak to. I would like to know what actually determines if I will need second alternator, or higher output, additional battery, capacitor or all of the forementioned. I have a 2000 blazer 4X4 with an alpine hu and three amps: 2 memphis sc16-sc2.120 for front(components 70 RMS) and rear door speaks (65 RMS) plus, JL Audio, JL J2 1000.1 for the sub (Kenwood KFC-XW 1225db).

Thanks in advance,

-TuType

Oh farque, you listen to audio forums and experts don't you? Well it depends on what you want. If your alternator isn't big enough you will: - drop about 2 volts whenever the load exceeds alternator output; - maybe flatten your battery if not recharged enough during driving; - maybe replace your battery more often due to its extra use. You will need a second battery if: - you want an independent battery for the amp when not driving/charging; - the voltage drops at the amp are too large during surges/burps. - the amp's current surges are too destructive. You will want a cap if: - the current surges damage your battery [ie, an AGM battery next to the amp(s) in BIG systems (typ >3kW)].    Apart from the last (which is generally the only reason for a cap), the others depend on your application (street, competition); your finances (can replace batteries often); your amp output power versus input voltage - and if that matters. I bet the reason you have previously gotten multiple answers is because no-one has specified else determined what you want. Plus if it is from the forums I have seen, they essentially give random answers with little relation to reality.

Its just the common answer I have also gotten when I have went in and asked questions of sale's men at different shops. Even told them my lights were dimming even when I had the rpm's at 3500 at idle. The most popular answer has been you just need to get a cap and that will fix your problems. That will keep your lights from dimming when your bass hits. Another place said one of these dry cell will fix all of your problems. None of the places said anything about what I really needed a better alternator.

Ah well, now that I know your question. A cap will fix your problem, though a small AGM may be cheaper and superior. I assumed you had an audio question, not a light question.

oldspark wrote: Ah well, now that I know your question. A cap will fix your problem, though a small AGM may be cheaper and superior. I assumed you had an audio question, not a light question.

I was just responding. But when I had my system a cap did not fix anything. I had 2 1 ferried band-aids just off the main amp. It was a joke. I got them for free so I figured I would try them. I also had large battery. At the time I was running a old Fosgate Power 500, a Fosgate 250 and a old Hifonics VII Vulcan amp. I was just pointing out what I was told by stereo shops.

Sorry, my bad - I didn't realise you were not the OP. I answered the light-dipping for the OP's set-up. (Though I should have mentioned the Big-3 - not that I described HOW to implement the fix.) Yours (dragon) is a different situation. You wouldn't put caps at the amps to fix dipping lights (in general). And only "one" big battery or a bigger 2nd battery? (The first situation is especially useless.) And that no-one suggested a bigger alternator? Geez, they weren't "audio experts" were they, or did they know that your alternator outputting (say) 14.2V under load?    The solutions to most AUDIO problems are covered by my first reply, though I omitted distribution/wiring (eg, the Big-3) and only considered audio and charging and not other problems like dipping lights.

What's an AMG battery?

Thanks in advance,

-TuType

Dunno. But AGM is Absorbant Glass Mat, aka VRLA = Valve Regulated Lead Acid.

I use a Optima Yellow top for my battery its a type of AMG there are others. Some don't like Optima very well, but I have not had any real problems from them. I also use them very hard, I use it in my Jeep with a Warn 8000lb winch. Oldschool Ya they were audio experts, the one place is a large chain store. The other is a run of the mill. Either way they did not know anything. lol

Ouch, yellows are not good for high drains (eg, cranking and winches) - usually reds are used. Alas I cannot recommend Optima. I hear or read far more of their failures than anything else, and Optima(Jim - former(?) Optima eCare manager) was unable to supply any data/info to counter that. However IMO many of those might be attributed to incorrect application - eg, a yellow top as the sole battery and used for cranking, or crankers used to power amps when not charging, or deep-cycles with big amp thumps etc. And of course all vary so much - starter and amp currents, wiring resistances etc. People often get AGMs for the wrong reasons. For audio & winches etc, the setup should be a second battery (probably AGM) but with a standard wet/flooded cell as the main battery - unless rich enough to upgrade that too. As to audio experts, excluding the12volt, my experience has been broad. You may see my other posts herein that comment on the FloridaSPL site (there are some people with good into, but OMG sme others - like engine-bay mounting for more battery capacity, the "100AH per kW" rule, etc), but there is heaps more. Unfortunately my recent findings support the (now-)theory that correct web info is diminishing - the incorrect (and costly) info is swamping the truth. But we should let OP tutype lead the comments & questions rather than us hijack with other discussions...