Do I need to upgrade my alternator/battery?

[Frambled 10+ year member]

Here is the situation. I'm going to install a rockford 10" p3 with an alpine m500 amp into a stock 2009 Jetta.

My Grandpa and Uncle are both very good with cars (but not so much car audio) and seem to think that the alternator and the battery won't be able to handle the system.

I'm new to car audio but I feel like people have pushed their stock electric systems a lot harder than I plan on doing; but I'd like to see some confirmations here (for my relatives sake) Can anyone back me up?

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[Fiendstolemyamp 10+ year member]

Should be fine. It's not like that's some huge current hog you're installing, just a 500 watt class d amp.

 

[Isaac 10+ year member]

You should be fine

 

[Frambled 10+ year member]

Thanks I didn't see a problem. I figured the guys running 3 12" Walmart subs probably don't bother with other upgrades.

and sorry for this thread that has probably been made 100 other times. I just needed my own to send off to my relatives.

 

[Sleeklsc 5,000+ posts]

Your stock alt is a 140a so you should be good to go.

 

[quackhead 10+ year member]

Here is the situation. I'm going to install a rockford 10" p3 with an alpine m500 amp into a stock 2009 Jetta.
My Grandpa and Uncle are both very good with cars (but not so much car audio) and seem to think that the alternator and the battery won't be able to handle the system.

I'm new to car audio but I feel like people have pushed their stock electric systems a lot harder than I plan on doing; but I'd like to see some confirmations here (for my relatives sake) Can anyone back me up?

Since there is only a 200 watt difference in 4 ohm power and the minimum 2 ohm power, the efficiency will be much better at 4ohms.

4ohms at rated 80% efficiency @ 14.4v:

300w/.80 = 375 watts input

375/14.4 = 26 amps

4 ohm current draw : 26 amps

2ohms at 500 watts with a realistic 70% efficiency at 14.4v:

500w/.70 = 714 watts input

714w/14.4 = 49.5 amps

2 ohm current draw: 49.5 amps

the difference between 300 watts and 500 watts is about 2db, barely audible. The 23.5 amps difference between 2 ohm and 4 ohm usage of the amplifier could be the difference between headlights flickering at night or not on your car.

So yes, I would fell very comfortable saying that if you used the MRP-M500 at 4 ohms, you will be fine.

One more side note - at 4 ohms rated power the amp produces .08% distortion, which is inaudible.

At 2 ohms rated power, it produces 1% distortion which can be audible at that power level.

hope this helps

 

[audiobaun 5,000+ posts]

You will be just fine with running that amp in that car..If anything, look into doing the BIG3 if anything, and will help on any vehicle /stock or running a system,to help on the electrical system..its easy to do,and will help maintain voltage..

 

[quackhead 10+ year member]

You will be just fine with running that amp in that car..If anything, look into doing the BIG3 if anything, and will help on any vehicle /stock or running a system,to help on the electrical system..its easy to do,and will help maintain voltage..

do you think 26 amps is going to require a Big3?

 

[audiobaun 5,000+ posts]

do you think 26 amps is going to require a Big3?

Whos to say?All vehicles are different when it comes to amperage drawl?? It wouldnt hurt??I feel like any and all vehicles should be done of the big three to maintain proper voltage,and prolong the alternator,as well as the battery,as we all know when you turn that a/c on ,how the voltage drops with the getting by stock electrical wiring is concerned..I stated he would be fine with that amplifier??Yes?Stated if anything,(considering doubts ect)to look into doing the big 3,and even gave a tutorial for this, as well as the alternator tutorial ,to get an understanding of ,and questions can be answered easily by both vids,rather than he says she says, with a hands on pro that explains in detail? And as for helping with the flickering of the lights youve mentioned meaning,the electrical is beyond its limitations , and within starvation of need:eyebrow: Its cheap, and can be done to any vehicle,as we all know,we break the cheap/a ss boundries of the bare minimum stock electrical?

 

[quackhead 10+ year member]

Whos to say?All vehicles are different when it comes to amperage drawl?? It wouldnt hurt??I feel like any and all vehicles should be done of the big three to maintain proper voltage,and prolong the alternator,as well as the battery,as we all know when you turn that a/c on ,how the voltage drops with the getting by stock electrical wiring is concerned..I stated he would be fine with that amplifier??Yes?Stated if anything,(considering doubts ect)to look into doing the big 3,and even gave a tutorial for this, as well as the alternator tutorial ,to get an understanding of ,and questions can be answered easily by both vids,rather than he says she says, with a hands on pro that explains in detail? And as for helping with the flickering of the lights youve mentioned meaning,the electrical is beyond its limitations , and within starvation of need:eyebrow: Its cheap, and can be done to any vehicle,as we all know,we break the cheap/a ss boundries of the bare minimum stock electrical?

I can't tell if u mad at me for asking or not...I was just asking though. but yeah, that's why I laid the facts down, so he would know exactly what's up...and I see your point on the Big 3 upgrade..I usually advise it on systems 500watts and up, but after researching and running the #'s on that little Alpine at 2 ohms, it would be smart to advise everyone to do it.