What electrical upgrades do i need

[rennocneb]

Runing a sundown SAZ-1500D Revision 1 at 1ohm along with a high amp making 125x2, in a jeep liberty with a 136amp alternator. Running a Deka group 34 under hood and just to test it stuck the old stock group 34 lead acid in the back. Still getting some dimming, dropping to around 12.5 volts beating on it at idle it gets a bit better with a rise in rpm but still seeing some dim. its not horrible but its there. Id like to get rid of it completly. I have a big 3 done, considering adding a second deka in the back. Will that gain me anything? or do ineed to go straight to an alternator? if so i have spoke to a couple of companies but no one uses the litens decoupler that my stock alternator does. Im told without the decoupler its hard on the serpentine tensioners etc on the vehicle. just looking for some advice on how to best handle the issue without spending a fortune or making things worse.

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[garychurch84 10+ year member]

How did you set your gains?

I don't know if I would run 2 different types of batteries go ahead get another deka

 

[murph 10+ year member]

Dimming happens to people who even have a good electrical. If the dimming is really intense then your voltage is dropping pretty low most likely. Just get a quality agm batt that has 75-100ah.

 

[rennocneb]

im seeing 12.5 volts at the battery posts and amp inputs on real heavy bass notes. I dont plan to run the two different types i was simply doing it for testing. Will the better battery in the back help more? its enough dimming im not wanting to just live with it.

 

[bbeljefe]

You probably have some resistance in your negative path due to the unibody construction of the Liberty. Make sure you have a very good ground connection or even run a negative from front to back.

 

[rennocneb]

anyone know the best way to poke a hole through the firewall on one of these things.

 

[garychurch84 10+ year member]

how did you set your GAINS?

 

[garychurch84 10+ year member]

You probably have some resistance in your negative path due to the unibody construction of the Liberty. Make sure you have a very good ground connection or even run a negative from front to back.

^this^

 

[rennocneb]

i honestly have just set them to a point of hearing distortion. i dont have a scope so i guess im going to take the multimeter to it to set gains.

 

---------- Post added at 11:03 AM ---------- Previous post was at 11:03 AM ----------

 

is there anyway to do a better ground without running a dedicated ground back i hate to pull all the interior again lol. secondly is there a way to check the ground for resistance.

 

[murph 10+ year member]

i honestly have just set them to a point of hearing distortion. i dont have a scope so i guess im going to take the multimeter to it to set gains. 

---------- Post added at 11:03 AM ---------- Previous post was at 11:03 AM ----------

 

is there anyway to do a better ground without running a dedicated ground back i hate to pull all the interior again lol. secondly is there a way to check the ground for resistance.

Either ground to the frame or try to find anything that directly attached to it and go from there. This whole different battery thing doesn't really matter. You don't need to run the same exact battery you have under the hood. So many batteries today are almost the same to begin with. Many people run with their stock battery and then put a secondary in the back when on 1.5-2k.

 

[rennocneb]

the liberty is unibody so no real "frame"

 

[rennocneb]

is seeing the voltage drop like i am common with a bad ground? i was assumming the alt just couldnt keep up?

 

[bbeljefe]

is seeing the voltage drop like i am common with a bad ground? i was assumming the alt just couldnt keep up?

Yes, it is very common. Any bad connection in the power circuit can cause dimming. If you put a broken link in a chain, it doesn't matter where that broken link is located... the entire chain is weakened.

As for where to ground, you may be able to find another location but a lot of unibody cars are assembled with epoxies now instead of welding so one panel may not be electrically bonded with the next.

You can use a volt meter to check the resistance in your ground wire but it will not show a weak connection. i.e., at low current your ground path may not be weak but once you start drawing higher current through it, resistance can increase. Your best bet is to install the system properly and run a dedicated ground. I understand that it isn't easy to do but you don't have to do it every day. Just do it right once and you'll be good.

 

[rennocneb]

just hate to go to the time and expense for no gain if that isnt the issue.

 

[bumpasauras 10+ year member]

You xan add batts as a band aid but you really need an alt. Auto Zone has a stock replacement you can order 180 amp for 136.00 with a lifetime warranty. that would be my next jump 180 amp alt and atleast 2 dekas will do it

I have my 2 ppi bk 1800's and 2 ppi phanrom 900.4,s running off of a duralast 180 amp with 3 xs 2400's and there is 0 dimming sta7s at 13.6 or better at all times. the saz 1500's prolly draw a bit more but not much. Just get an alt of 180 amps or more and you will be good.