JL 1000/1 V2 Slash amp with Pontiac G8 GT Electrical System?

Aug 1, 2010
Philadelphia, PA

I recently purchased a JL 1000/1 v2 slash amp to power a JL 12W7 sub in a ported box. I am using 4 gauge wire. However, I have read of people having alternator problems or voltage errors due to using the amp (it is supposed to be very hungry). I drive a 2008 Pontiac G8 GT. My questions are:

1. Do I need a 2nd battery?

2. Do I need to do anything to the alternator?

3. Would it be worth it to get a 2 farad capacitor? I have heard mixed things about capacitors. The guy at the audio shop told me they are like bandaids and won't help much. However, I do not want my headlights dimming and would prefer to minimize load on my electrical system. Would a capacitor help for these things?

Any other comments or feedback regarding this setup? I don't know anything about this stuff so if someone could look up the electrical information on the G8 GT and let me know how this amp would fair and anything I would need to do, that would be great!





Bat Country
10+ year member
Aug 12, 2009
The only down side to the JL Audio Slash series Class D amplifiers is that they have near Class AB efficiency due to the fact that they produce rated power at a variety of impedance loads AND voltage loads.

I'd recommend a second battery before I could ever in good faith recommend a capacitor. The only use capacitors have ever been to me was to filter out power line noise. Other than that, they are utterly useless for "storing" energy because it takes less than a fraction of a second to drain a capacitor. Furthermore, that will tax your electrical system even harder because it must refill the capacitor while supplying current to your amplifier. The main reason capacitors seem to "help" those with dimming problems is because the capacitor becomes the bottleneck in the system versus the amplifiers causing parasitic drain.

Also, keep in mind that a 2nd battery will be an additional strain on an already taxed charging system. I've done the 2nd battery thing where I charged my 2nd battery once a week on a battery charger and it worked out fine. I've also done the upgraded alternator thing with the biggest battery I could shoehorn into the vehicle and that worked out well too for 2,000 watts RMS.



Jan 24, 2010
you do not need a 2nd battery. do the big 3 upgrade DO NOT USE A CAPACITOR they are time booms if you thank about it. they like to pull power an drain batter's.do that then go from there i don't thank you will need to do eny more.



10+ year member
Jun 28, 2009
Douche, Ohio
Get a good batt, not sure if yours is in the front or in the trunk, but you need a big three for sure. GM loves cutting corners. get something dry cell/ agm

Aug 1, 2010
Philadelphia, PA
Thanks for the help guys. However, is it necessary that I do a big three upgrade or will I be ok? I emailed JL and they told me that the 1000/1v2 draws between 80-100 amps when driven at maximum output level. Since the 2008 G8 GT has a big engine, the alternator puts out a decent amount. I looked online and the G8 alternator is rated at 155 Amps (108 Amps Under Load). Since the amp will only draw 80-100 amps, would I be ok with NOT upgrading my battery, NOT upgrading the alternator, and NOT getting a capacitor? I also don't want my headlights to dim...

Just so I am clear, with the above power rating details, will my headlights most likely dim? Would a capacitor be totally worthless? A capacitor wouldn't help in cases where the alternator was generating somewhere close to 100 amps under load and the amp was drawing 100 amps?

Any other comments would be helpful.




10+ year member
Nov 30, 2007
barksdale afb, louisiana
this amp is really good on your electrical, but you should at least do the wire upgrade and a decent battery. i ran this same amp for a year on a 55a alt and redtop on two fissd 12's with very little issue, and it was loud and clean. i also had the big three done and it did make a difference. you alt will be fine with this amp, like i said get a better battery and big three.


Create an account or login to comment

You must be a member in order to leave a comment

Create account

Create an account on our community. It's easy!

Log in

Already have an account? Log in here.

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Trending topics