I have a kenwood excelon kdc-x979 head unit!i also have 2 kenwood excelon kac-x811d amps,1 kenwood excelon kac-x541,my problem is when my bass hits my voltage drops way down.i tried caps.im running 4 gauge power wire. i have good grounds.My manuals say current consumption is 55amps a piece for the 811d and 45 amps for the kac x541.at 4ohms. im running the 811d in 2 ohms.What size alternator should i use!!!!!!!!!!!!

 

Current pull probably isn't that high unless you're really playing pretty loudly.

Before you do anything I would try upgrading the big 3: chassis to battery (negative), engine to battery (negative), and alternator to battery (positive). This will give you a much better grounding system and you can do it with less than 5 feet of wire in about a half hour. I did it with 2 gauge and noticed a pretty big difference.

If that doesn't fix your problem go out and get an alternator. You can go as crazy as you want, it doesn't really matter. When you're shopping you want to look at how many amps the alternator will put out at idle as well as cruising rpms. An alternator with 10-50 amps less peek output might be better for you than an alternator that peeks higher but puts out jack squat at idle.

 

ThANKS for the advice,the big three you mentioned were all done already.My battery discharges in traffic and at traffic lights.When i stop any where i have to shut the radio and let the car idle 5 minutes to recharge,I also have to leave the radio at low volume if its raining I cant use defroster and headligthts and wipers + radio.would you use 140amp or 200amp alternator?????????/

 

If you don't already have a 140 amp alternator you can buy the CS 144 (the GM high output alternator). It will be your cheapest option. If you want piece of mind you can always grab a 200 amp powermaster or something else along those lines, but you're going to be shelling out $300 plus. There are also a few guys that sell custom high output (200+) alternators online but I have no idea who any of them are. Maybe someone will step in and offer a link or a name.

If your battery really discharges at traffic lights then you might want to look at a larger (or better) battery. What are you running now? How old is it? Have you tested it recently? Odds are that it's not up to par anymore if you're able to discharge it that quickly.

 

you have to put at least the voltage you take out.back into the battery.which at idle in trafffic is not enough. i havve a yellow top optima!!!!!Ill go with the 200amp to be safe,battery is new so is all wireing

 

You do have to recharge the battery, but assuming the battery has been charged through cruising around town/on the highway, etc you shouldn't be able to kill it off during 5 minutes at a stop light.

Food for thought

 

iraqqi makes very nice alternators. you can reach dominick iraqqi, the guy that makes them at Dominick@tds.net or call him at the shop at 615-617-7991. hes a good guy and he REALLY stands behind his products 150 percent. i have an excessive amperage alternator, mine works great, but a lot of people have had issues with dead or poor charging alternators from then so i wouldnt recommend them. all this started going down after i got mine, they used to also be top notch.

i'd recommend a 200 amp. im pretty sure a large case will work, and would recommend one of these also. most 200 amp small case alts dont do well at idle. mine drops to about 12.3 at idle (650-700 rpm) but is 14.4 at 900 rpm. i just like the lower, lopier idle, so i dont slam my **** at stop lights. that pisses people off anyway.

 

Im saying with no accessory when the bass hits. stopped at traffic lights my volt gauge dips to ten volts .your battery will die even if its a garbage truck battery if your only putting ten volts back in.Apparently the larger alternator is my only choice.the 200 amp is a wiser choice then the 140 amp.

 

hell before i upgraded my alternator, just my old eD nine.1 amp at 1 ohm and a kenwood 35x4 used to drop the voltage so hard the car would jerk while i was driving, even on the interstate. and thats at 2k+ rpm since i have steep gears. doing the big 3 in 1/0 gauge helped a little, but it still did it noticeably enough to be embarrassing until i got the new alternator.

 

oh and nice deck you've got there

 

Overdrive your alternator with a smaller pulley, so you get more amperage in traffic at idle. Cheap and solves the problem.

I'd recommend a CS 144, like from a '95 Chev Lumina van or the like. Rated at a 140 A and backed by GM so you know it's a high quality product.

150 A and you're using 4 AWG? I'd recommend 1 AWG personally.

Try this:

Have all accessories off, measure voltage at battery terminals, then at terminals on amp, then turn on every voltage drain you have, measure voltage drop on battery, and at same amp. Look at results and find your problem.

 

I agree. 4 gauge is only good for 130 amps max, meaning you want to stay below this. This is also a fairly decent set of evidence that your amps are not pulling to their full capacity (not that that's a bad thing - it just means that your power system might be put up to a higher task if you turn it up more).

2 gauge should do you fine at 208 amps. 1 gauge is rated for 262 and 0 for 330.

 

what?
where are you getting those numbers?
like what distance of wire?

basically, the thicker the wire, the shorter the distance, the less voltage drop, less voltage drop means you have higher voltage, so you can make more power with equal current. or make same power, with less current.

I'm using 1AWG welding cable, since I got it on sale, and I will have very little loss in the cable, plus if I decide to upgrade, or add on electrical items in the back half of the car, I can just hook up to that distro block.


anyway, i'd check your voltage levels as I mentioned, to find the source of the problem. It's definately a problem, like something is broken or wrong, not just something isn't good enough.

 

IM using a stock alternator right now. i called the tech department at kenwood theyv told me 65 amp is big enough.No way.I thought i would give thirdgen a shot at helping me out.im running 2 seperate 4 gauge power wire an 1 8 gauge power wire