4 batteries still low voltage, HELP.

[Alejandro14]

first things first equipment.

1. soundstream headunit 2 volt

2. 2 american bass xfl 10442 tune 32 hz

3. c2 recon 1.6 amp at 1 ohm rated at 12v 1600 & 14.4v 2050

4. mechman 240 alt

5. big 3 0 gauge ofc

6. memphis 4 channel amp 4 ohm 50x4

so in engine bay i have a yellow top optima model D31T 75 Ah running 0 gauge ofc wire back to my second battery xs power 750 20 Ah from this battery parallel wire 4 gauge to my next yellow top optima model YEL51R 38 Ah then my last battery is another same YEL51R 38 Ah also 4 gauge wire they are like 6 feet away all 3 batteries in back. my 2 amps are connected to the xs battery sub amp has 0 gauge power and ground. Here is the trick when i check my voltage up front with multimeter on cold starts 14.4 on bass note 35 hz it reads 14.4 to 13.5 at idle but on my amp it reads 12.7-9 ..... is the xs power cant feed my amp good power ?

truck is a 2007 ford f150 dont have to much space for bigger batteries thats why i buy small batteries.

Click to read more...

 

[evilmonstertruk Premium Member]

Are you using the same DMM to check up front and by the amp?

Sent from my SAMSUNG-SM-G935A using Tapatalk

 

[LosIsATool 5,000+ posts]

Bad grounds

 

[dbjunior 10+ year member]

Check your grounds sounds like voltage drop from front to back.

 

[Alejandro14]

well front battery has 2 runs to a bolt on frame also another ground from alternator to same bolt.... back batteries i grounded all 3 negatives behind the seats to the frame were the seats clip even the amp i ran it with those 3 cables.... please help me give me suggestions were else can i ground too... also i forgot i have alot of engine whine to my speakers and when eve i turn my basas knob 1/4 the subs make a hmmm sound ... i tried grounding the rcas nothing group isolator nothing .... thanks guys anything you guys suggest i need to try here were i live not to much stores.

 

[LosIsATool 5,000+ posts]

It's not the quantity. You just have more room for errors. If you have whine you have a bad ground

 

[Alejandro14]

can the headunit send dirty signal if not grounded properly?!? because this guy install the radio for me at his shop but idk if he installed it rite ... i saw the cable on headunit it has the label " ground " and its connected with 2 other cable together ..... how can i check for bad ground ?

 

[dbjunior 10+ year member]

You want to check the actual ground for corrosion or rust make sure there is no paint under them. You want the lug connected to shiny metal.

 

[dragon.breath 10+ year member]

you need to either ground the rear batteries/ amplifiers to the frame of the truck or run a negative cable from the front ground Point too the rear.

 

[n2audio 5,000+ posts]

I'd be curious to know if the voltage goes up any if you disconnect the 3rd and 4th Optima's temporarily.

 

[2twelves]

Hay bro see a couple things wrong if you know your head unit has low volts just get a eq like clarion 7 volts each input front back and subs All your wires should be 0 gauge even going to your amps use those double inputs they are like 15 bucks. Dril threw floor get to your frame for ground so important that's for your battery's in back.ok now this is where I'm still studying and am trying to find out.can you skip that yellow cause it's good for your car not your system.can you just run from the alternator straight to the back to the really good battery's .what do you think

 

[2twelves]

I had bad engine whine got alpine head unit more volts better rcas 20 bucks to subs 30 buck 4 channel for rest ran all twelve gauge good speaker wire ocf whine gone

 

[Boomin_tahoe 5,000+ posts]

What is it with you and speaker wire???

Bad RCA's is what you had.