Questionalright, any info on the imput voltage of the amp though? i hate to think that iv put all this money into the system and need to buy a new head unit or worse yet fry my amp
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alright i think iv got the hang of this, a coupple other things that this brought to mind.
1.first of all u were talking about the guage of wire, i still have the first wireing kit installed in my car, pretty cheap, 8 guage power and ground. the new amp im getting says it requires 4guage power and ground, if i do the second battery idea will i be able to run the 8g wire from my hood battery to the trunk battery and then to the amp i was thinking since its so much shorter distance to the amp i wont need to buy a 4g kit, i dont know if my assumptions are right though, if not is it safe to buy a short section of wire for ground and power from say home depo going from the trunk battery to the amp, and will the 8g be big eanough for the batteries, the wire has a 60amp fuse in it by the way.
2.the infinity amp says it has an imput voltage of 5.7 volts. i wasnt sure if that is from the battery or from the head unit. if its from the battery i dont see any problem but if its from the head unit from what iv heard the normal volt rating on most car audio is 5 volts. i have a more ore less high end sony explod head unit CDX-F7715X, i believe is the product name, i cant seem to find anywhere on the manual or the internet what the voltage ouput is, should the head unit be able to support the amp if that is the case?
sory i asked so much but when i get into somthing, like car audio, i realy get into it i like to know everything about what im doing haha.
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hey i have 2 10" infinity perfects 350watt rms in my trunk now and i am planing on getting the infinity 1211A amp which is 1300watt rms at 2 ohms, i am currently running them off an alpine amp at about 150rms, i am concerned about my alternator failing on me and i heard that u could hook up another battery in your trunk and wire it to your main battery under the hood positive to positive, negative to negative and then run the amp off the trunk battery. he said he wasnt sure if this was correct though just wondering if u have any imput or better ideas? thanks a bunch
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you sure can use a 2nd batttery and there are alot of pros and some cons to this. I own 3 cars and 8 car batteries between the 3 cars so do the math!!!!
I really like having a 2nd battery in the trunk, it allows you to run a thinner gauge wire in most cases and provides better performance in most cases as well. there's also advantages if you take the extra time to put in a switching circuit, you can play your music off the rear battery with the car off and even if you drain your rear battery you can still start your car off the front battery! there is also the pro of reduced load on the alternator.
the disadvantage to the rear battery is #1 of course, cost, you have to buy it! #2 dangerous, you dont want to go grocery shopping and throw a bag of canned soup on top of the rear battery or even chance the bag of canned soup rolling around and getting against the terminals of the battery so you need to consider that. And #3 the fact that amps require instant, spikey amounts of current and car batteries dont provide this too well. even so, it helps. the other little problem that 2 car batteries together can have is that they tend to drain eachother. batteries naturally drop voltage over time, but if you have 2 together, as one drops, it tries to charge itself off the other one droping it, which in turn tries to charge itself off the other one and around and around you go. personally I havent had much problems with this, as long as both batteries are in relatively good shape and you drive the vehicle about 40 miles a week you should be fine. if you are buying a new battery for the rear you should consider getting a new kinda matching one for the front if the front one is old. I LOVE the yellow walmart batteries, they are cheap and have a 3 year warrenty.
as for hookup, you just mount the rear battery securly, drill a hole in the body of the car to anchor a ground, sand the paint off around the hole, and ground the battery just like you would an amplifier with a nut and bolt and ring terminal on the ground wire etc.
then the wire you have going to your amp now (if its a decent gauge) can simply be connected to the posative of the rear battery, this will conect the 2 batteries. the you just run a new wire from the rear battery to the amp. done.
if you experience the problem where the 2 batteries drain eachother then we have to put a relay system in to separate the batteries when the car is off but as I said, I havent had this problem.
I would also sugest using a capacitor with this amp.
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well, there are a few things to consider with the gauge of the run between batteries. there's 2 schools of thought. one says, when you add a rear battery, the system works like this:
the alternator's job is to just keep a charge on both batteries, the rear battery bears the brunt of the load to the amplifier, so the wire can be light gauge to the rear battery cuz all it needs to do is keep it charged so it can do its job.
the second school of thought is that the altenator will always have more voltage than the batteries. the batteries will be like 12.5 volts but the alternator should be between 13.8 and 14.4 volts and that seems insignificant but its not in actuallity, it matters quite a lot. so basically if there is a light gauge wire between the 2 batteries, the amp under light load will get 14.4 (or whatever your alternator puts out) but as the amp requires more juice (specifically more than the run between batteries will provide) the power will dip to whatever the rear battery is at.
to sum this all up, the fatter the wire, the better (the more the alternators power will transfer to the amplifier), but if the wire gauge is very light, the wire will still do a good job of charging the rear battery, and the rear battery will run the amp, but with the light wire, as the amp draws more juice the power will fluctuate between the power the alternator provides (14.4 ish) and the power the battery provides (12.5 ish)
I guess if I had to sum it up even quicker, fatter wire is always better but not always nessesary??? why dont you try the setup with the 8 gauge you already have and see what happens. I think it should be fine.
as for wire from the rear battery to the amp, use the wire the amp is recomended for, in your case 4 gauge wire. even though the run is short from the amp to the rear battery, use the 4 gauge wire, you wont be sorry!
sorry if this is all complicated but I hope it all helps!
Answeroh man sorry! I cant beleive I left out a major part of your question there!
the input voltage they're refering to is the maximum voltage the RCA inputs can take before clipping from the head unit.
most head units put out 2 volts max and the more expensive ones put out 4 or 5 volts.
its nothing to be concerned about at all. usually the higher voltage the less noise gets picked up in the signal. what they're saying is your cd player should basically be under this number which it is so you're good! even if your unit only went up to 2 volts or even 1 volt there is a knob on the amp called "gain" that adjusts for this. No problem either way.
