Print Page | Close Window

how do i calculate system load?

Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=94867
Printed Date: December 05, 2022 at 8:36 AM


Topic: how do i calculate system load?

Posted By: may03lt
Subject: how do i calculate system load?
Date Posted: June 17, 2007 at 1:30 PM

Hey dudes! Im planning for the second (and hopefully last) part of my little system. As far as I know I do not have any charging issues right now with the factory charging system in my 03 Trailblazer with the system I have now and the way the sub amps are wired. I had a dmm hooked up to the alt with the a/c, lights, and system on, and did not go below 13.9v with my current set up.

Current set up:
(2) RF P8002 (4ohm stereo/ 120A each)
MTX 8302 (2ohm stereo/ 60A)
Alpine 9857 (10A) Kicker KX3 (10A)

New set up:
(2) RF P8002 (4ohm bridged/120A each)
MTX 8302 (2ohm stereo/ 60A)
MTX 4122 (4ohm stereo/ 20A)
Alpine 9857 (10A) Kicker KX3 (10A)

What is the proper way to determine the load of the system, and how can I use that to determine what upgrades may be needed in the charging system?

Thanks!

may03lt



-------------
2003 Trailblazer LT
2007 Envoy SLT



Replies:

Posted By: may03lt
Date Posted: June 18, 2007 at 2:46 PM

Ill put it another way:

Will my factory electrical system be able to keep up with 2,300 wrms?

If not what should be the next step?



-------------
2003 Trailblazer LT
2007 Envoy SLT




Posted By: may03lt
Date Posted: June 19, 2007 at 7:28 PM

hmmmm

searched the topics
didn't find the answers
asked the questions
got nothing

cant anyone point me in the right direction?

come on its good karma if ya doposted_image

wheres the love?

may03lt



-------------
2003 Trailblazer LT
2007 Envoy SLT




Posted By: jmelton86
Date Posted: June 19, 2007 at 7:35 PM

Figure out load on amp here:

https://www.the12volt.com/caraudio/woofer_configurations.asp

Do the Big3 Upgrade:

https://www.the12volt.com/installbay/forum_posts.asp~TID~73496~PN~1

The next step would be a red top [or two - in parallel straight wired to each other (no isolator or circuit breakers)] and a high-output alternator.



-------------
2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001




Posted By: may03lt
Date Posted: June 20, 2007 at 8:22 PM

Thanks bro!

See this is where I'm stumped - if the amplifiers are pulling 170A (I used the RF amp calculator that I never knew existed)  why would I need 2 batts? Would I just need an alt that will support the truck and the amplifiers? I will never listen to it without the truck running, that why I ask.



-------------
2003 Trailblazer LT
2007 Envoy SLT




Posted By: zhalverson
Date Posted: June 21, 2007 at 1:49 AM

Yeah, an alternator that can keep up is all you really need as long as your battery is in good shape.  2 batteries would only really help if you were listening to it off which you said you wouldn't be doing.





Posted By: may03lt
Date Posted: June 21, 2007 at 8:48 PM
ok, so should I take the requirements of the truck and add 170 to determine the amperage of the alt? And how do I figure what size battery to get?

-------------
2003 Trailblazer LT
2007 Envoy SLT




Posted By: jmelton86
Date Posted: June 21, 2007 at 9:13 PM
Yes, that is the proper way to determine what size alt to get. Just get a Red or Yellow top battery. Make sure to do the Big3 Upgrade with alt upgrade. It may void the warantee on the alt if you do not.

-------------
2013 Kia Rio -90a alternator
DDX470HD GTO14001 GTO1014D (x3)
Big3 in 1/0G
1/0G to GTO14001




Posted By: zhalverson
Date Posted: June 22, 2007 at 12:52 AM

Like I said if you're existing battery is in good shape you don't need a different one and if you're not running the stereo while you're vehicle is off you don't need anything bigger than what you have because the alternator will provide the power.  No need to waste money in my opinion.





Posted By: aznboi3644
Date Posted: June 22, 2007 at 5:23 PM
An extra battery will help if your alternator can keep it charged.

When there is a big load on the alt and the voltage drops fast...the voltage won't drop as low if you have another battery to help support that draw




Posted By: zhalverson
Date Posted: June 22, 2007 at 6:08 PM
If your alternator is able to support the load, which is why you upgrade the alternator in the first place, why would the voltage be dropping so low?




Posted By: may03lt
Date Posted: June 23, 2007 at 5:59 AM

The trailblazer needs 75A, the system needs 170A, and Ohio Gen makes a bolt on 280A.

I'm thinking of doing the 280, a kinetik 2400, and 1/0 big 3.

Sound ok? Opinions?



-------------
2003 Trailblazer LT
2007 Envoy SLT





Print Page | Close Window