I have an amp that draws 150 Amps, and a 110 Amp alternator. What do I need?

That Sundown amp running at 1 ohm will draw A LOT of current - especially at high volumes. I'm not a bit surprised it's cutting out. However, it sounds more like the head unit is shutting down first, which in turn is shutting off the amp. In the end, I don't doubt it's the amp that's causing voltage to sag.

1st - I recommend looking into spec sheets, user manuals, etc. for your head unit to confirm there is some sort of undervoltage shut off function. This would rule out other areas for concern.

2nd - Upgrade your alternator if you love loud bass at idle.

In the future you may want to look another (or dual) battery solution. Something with a higher CCA. XS Power batteries have received good reviews from bass heads, but be prepared to spend a pretty penny.

 

Hes only playing around 1500 wrms a second alternator is a waste of money. He just needs a good battery. Also red top batteries are not designed to be a true deep cycle battery but instead a much better starting battery. XS power battery good yes but he could get away with a lot cheaper.

 

deep cycle battery?...discharge/recharge is not his issue. His issue is not enough juice available during idle. When he's driving and the engine is at higher RPMs, the alternator is putting out enough current to keep up with the system. When he's idle and the engine is at lower RPMs, the alternator cannot keep up.

His options are install a higher output alternator or higher CCA battery.

 

Here is the skinny:

At idle, the alternator's output is only capable of 50%. That means that your alternator at idle can only produce 55amps. Alternator rated output is normally at 2000 RPM or higher. So THIS means that for your alternator to put out it's rated 110 amps, your engine will have to be running at 2000 RPM or more.

Since this is NOT the case, the subwoofer amp is drawing the alternator down, and draining power from the battery. (This is why your voltage drops to 11) Many high end or even factory quality stereo systems cannot operate properly at low voltage. In order to protect itself the stereo will power down and reset (Hence your aforementioned lower volume when the stereo "reboots") and this is what you are experiencing.

So what can you do to take care of this problem? There are several options.

1. Get a different alternator that is capable of 150amps of output at idle.
2. Get a custom pulley for your stock alternator to increase the armature speed. (Hard to find on many vehicles, but they do make them)
3. A combination of 1 and 2 where you get a smaller pulley on a better alternator.
4. Get a dual alternator setup.
5. Don't run your stereo at high bass when idling (Least desireable, but still an option)

Getting an additional battery is like putting a band aid on a gunshot would. It might slow down the bleeding a little, but eventually you will still bleed to death. Now that is not to say running a capacitor or a second battery is not a good idea. It actually is. But to JUST run a capacitor or a second battery is NOT the best idea. Hope my information helped you out.

 

I'm no expert at all but I would think that if your head unit is shutting down than that would be the 1st thing to check.

 

I came to this conclusion as well. I have a yellow top on the way, will be here tomorrow.

Great answer. Thank you very much. I'll try the battery first, and maybe look into a higher output alternator later on. And I'll make sure to check the output at idle as well, so I don't run into this problem any more.

After a couple hours of reading in the manual, I found that the deck does indeed have a low voltage protection circuit. When the voltage in the vehicle drops below 10.5 volts, the deck will shut down, and restart with a lower volume setting, protecting the battery. So that answers my shutdown question.

 

Exactly what I expected. Glad to see you are on the right track!

 

I have this same amp (used to power a pair of SA12's in my 07, i plan on reusing it to run 3 SD10s) and if i were demo'ing it sitting still, i'd make sure to jack the revs up (usually to around 2200 to compensate for when the alt gets a load on it and drags the motor down) I had (and still have) an odyessy PC1700, and a kinetik HC600 in the back, volt drop @ the input of the amp would get down to 12.8, sometimes a little lower depending.

Steve Singer makes some good H/O alts, i had him quote me ~400 for a 205a alt, you can specify your voltage too, I know our trucks like to run at 13.5 warm which isn't ideal. I would start w/ an alt personally before adding another batt, then if needed add a smaller one in the rear, kinetik has the 600 and the 800, both of which are small and easy to fit in tight spots

 

How much you willing to spend? You don't have much at the moment adding a second battery is a better option or buying a new larger battery depending how old that battery is. You dont really want to mix old and new battries. As it was mentioned adding a battery is a band-aid but you get a simple float charger and hook it up weekends or everyday which you prefer. You could spend a lot less and it could last for a while. I have 2 AQ 2200 amps and 2 AQ 120x4 amps. I ran my entire system off my stock alternator 110a and just a single xs power 5100 for a few months with no issues until i got a high output alternator and addition battery xs power xp3000. Before getting a high output alt you may want to research before the purchase. Here a couple i would suggest.
http://www.mechman.com/
http://www.dcpowerinc.com/
http://www.singeralternators.com/

 

Thanks for the links. I'll look into cost on those. I got the bigger battery, but I know I'll need the alternator too.

 

Actually that is an almost perfect voltage to run for most vehicles. I see a lot of GM trucks that average 14-16 depending on load. The battery is a 12.6 volt, so if you are at 13.5 that means that the alternator is putting out enough to charge the battery, and maintain the accessories currently on in the truck. I'd be happy there.

 

I was still getting the dimming lights, and the occasional shut down, even with the new Yellowtop. So I went through all my wiring again, and decided to redo my grounds. That fixed the dimming issue. I can now leave it cranked at idle, and have good battery voltage. An upgraded alternator is still in the works, but this is a good bandaid solution for now.

 

I was saying purely for car audio purposes, higher voltage means lower amp draw, not that it changes wattage, but it makes for a much stronger electrical system when it can charge around 14.6-15.2. I know when cold, the stock alt likes to hit at around 14.2-14.3. Ive seen it drop as low as 13.1 (very hot, not auxiliary load other than default vehicle functions)

not that it is a perfect example, and i am certainly not questioning your automotive knowledge (i know we've butted heads about tint before) but think about washer/dryers or large air compressors, they run on 240v so that they dont consume such a high amperage, similar logic can be applied to the car audio market.

 

"I have an amp that draws 150 Amps, and a 110 Amp alternator. What do I need?"

Hearing aids, in about 5 years, tops. Good luck.

 

Ear plugs for your passengers.

 

upgrade the "big three" wiring, install a second battery.

i have a car audio battery for sale since i dont actually do anything with it anymore.

 

What kind? How old? What is resting voltage?

 

^ kinetic hc2400, resting voltage

but i might end up throwing a stereo together in the tacoma after all.. Been looking at stuff all night and since i have a good portion already.. its a mighty tempting proposition lol

 

^ that and price has dropped to $300 and change new with free shipping (vs $400 something when i bought it) and at 70 lbs or so its probably going to be expensive to ship

 

it was one of two battery system in my old car

factory specs
http://www.kinetikpower.com/2009/product.asp?C=1&P=KHC2400

they boast a little much i bet but it worked great when i replaced the 2 optima yellows that preceded it