For those of you with amps/subs

tumanator · **Posted:** Mon May 11, 2009 7:41 pm

I'm installing a new HU with a kenwood amp and kicker sub, nothing extreme just a 10". However I'm installing 4ga wiring to the amp and sub for "future growth." My question is, has anyone noticed extra strain on the batter or alternator, should i look at upgrading to the 160 amp alternator and a different (other than stock) batter. Or am i fine to run it the way it is? I'm also gonna upgrade the 4 stock speakers and proly the 2 tweeters to the alpine component system (proly not an extra amp though the HU should do fine on it's own.)

hardhittinz · **Joined:** Tue Jul 03, 2007 10:44 pm **Posts:** 195

your fine with the stock alt and battery i run a 1800 watt amp with no problems..

JL Rockies · **Posted:** Mon May 11, 2009 11:58 pm

Most amps on the market today never have the chance to produce their ratings because the charging systems in vehicles cannot produce the required voltage nor amperage.

Your charging system has no problem with your 1800 Watt amp because it's not producing 1800 Watts. If it were, you would need 144 amps assuming 100% efficiency (which it's not) just for that one amp. Since thats more than your charging system can handle it must not be happening. Physics are a biotch.

All you really need to do is look at the box.; you see the rated output is at 14.4V input. None of us drive vehicles that maintain 14.4V output under load (or any other time) so the ratings are all bogus. It does make you feel better about your purchase though.

There's only one amplifier company out there that still uses an honest 12.5V (true input voltage) rating. The rest of the crowd is all smoke and mirrors made in the same Chinese factory. Amps are more of a fashion statement than anything these days.

tumanator · **Posted:** Tue May 12, 2009 12:21 am

lol, I know a little bit about how electricity works, all an amp is, is a glorified transformer with a few added capacitors for continuous "increased" output. My only question was of the quality of the jeep alternators, I had this sub in a 91 ford ranger before i bought this jeep and I believe I killed the alternator in it. Granted yes there's a good 14 year difference in technologies there too but I was really hoping to get out of the days where my headlights dimmed every time the bass hit.

Plus I honestly never looked to see what the stock amp draw is on these jeeps, I know the battery is supposedly capable of peak 600, (again with variable loss), with these newer vehicles everything is electric, I don't know what my "play" is, but it sounds like the alternator can keep up, your running a far hotter system that I am.

tjkj2002 · **Posted:** Tue May 12, 2009 12:58 am

The stock 136amp alternator is more then enough,plus with the KJ's charging system adding the Renny's 160amp alternator is useless since it will not take advantage of the extra 24amps since the PCM is not programmed to.I'd upgrade the OEM battery to a Optima Yellow Top(group 34/78 ) or a Odyssey PC1500DT battery since the amp is wired to the battery and not the alternator and a good battery will keep the lights from dimming and handle the load better then a lead acid battery will.

JL Rockies · **Posted:** Tue May 12, 2009 1:46 am

All energy to move a speaker comes from the alternator. All the amplifier does is take the energy from the alternator and convert it to some thing useful to do work: converts DC voltage to AC to run an AC motor (speaker).

That being stated, all the amplifiers in the world cannot produce more average power than the alternator has to give..... period. A 136 amp alternator produces 1700 Watts. A good chunk of that power has to go to the various vehicle operations leaving about 700 Watts +/- for your stereo.

Since the battery does not generate energy, it has zero impact on how much average power over time your system can produce. Once the battery starts the vehicle, it instantly becomes a load on the charging system as it recharges. Meaning there's even LESS juice available for your system.

The batt will act as a reserve for when the charging system is overwhelmed but since there's no free lunch, it will again be a load on the charging system as it gets recharged again. When this can't happen, you get your dimming lights and all other manner of electrical disfunction.

Your amp does not have a regulated power supply so it will work fine on whatever your charging system has for it. If voltage sags, so will the amplifier's output. These non regulated power supplies and very charging system friendly and will work just fine with whatever it's connected to. It will not however be producing the silly rating the manufacturer told you it would.

CRDMiller · **Posted:** Tue May 12, 2009 2:18 am

Interesting posts.

I dont know about your amps, but i have a 500/1 slash series from jl audio (witch is inarguably one of the better amps to ever hit the street) on a 12w7/w jl's HO wedge enclosure. It is rated at 500 watts output, on the cover.

It has three stages to choose from when driving a load, and can vary those stages on the fly. What this means is that it can provide constant output with in a wide range of inputs, for instance it's rated at 500 watts from 10 to 15 volts

However;

Output Power (Resistive) (4 ohms @ 60 Hz to 1% THD+N): 605 watts @ 14 volts; 601 watts @ 12.8 volts; 591 watts @ 10.5 volts
Output Power (Resistive) (2 ohms @ 60 Hz to 1% THD+N): 620 watts @ 14 volts; 604 watts @ 12.8 volts; 598 watts @ 10.5 volts
Output Power (Reactive) (4-ohm IHF Load @ 60 Hz to 1% THD+N): 639 watts
Output Power (Reactive) (2-ohm IHF Load @ 60 Hz to 1% THD+N): 733 watts
Crosstalk @rated output, 20 Hz to 20 kHz: N/A
Damping Factor, 2 ohms @ 50 Hz: 225
Voltage for Rated Output: 72mV to 8.3 volts
Idle Current Draw: 1 amp
Current Draw @ 1/3 Maximum Power: 26 amps @ 206.3 watts
Efficiency @ 1/3 Maximum Power: 57%

For all normal uses, i assure you, this amp does not see above 30% output.

Also My liberty's electrical system delivers 14.5 volts While running.

The sub/amp combo can EASILY STALL my wife's 2.2 liter saturn l200, it has a 67 Amp alternator. And to be honest that motor is pretty nice. This is also extremely pain full on the ears.

JL Rockies · **Posted:** Tue May 12, 2009 2:44 pm

You have identified the only amplifier manufacturer that uses a true in car voltage to rate amplifiers. Your amp has a regulated power supply which will draw more current as input voltage sags to maintain it's output. Regulation is not cheap, put I bet your 500 Watt amp is producing more output than the 1800 Watt amp from the other guy.

JL Rockies · **Posted:** Tue May 12, 2009 2:47 pm

I have a 500/5 running my whole system.

I ca assure you that your charging system is not producing 14.4V under load. No one's is.

For those of you with amps/subs

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