Voltage decline

[terra 5,000+ posts]

2 days ago everything was fine. At idle I would be at around 14v, driving id be at 14.7. Now at idle im around 12.1v and driving, 13.2v. I retightened all my connections and cant think of what else it could be.

Load Boss 250amp alt

2 Kinetik 2400's

1 Deka Intimidator

Stock up front

Big 3 done

What could be the problem?

Click to read more...

 

[fbi90909 5,000+ posts]

stocks probably dead and draining the others.

had that issue when my stock went to shit, but my voltage was lower. have your batts checked.

 

[terra 5,000+ posts]

ive been running this setup for close to a year.

 

[jrwalte 10+ year member]

It's either one of the batteries going bad, as mentioned, or your alt is going. I'd have each battery load tested and do a load test on your alt.

 

[skmfkr 5,000+ posts]

i was also thinking the stock batt. test the voltage of all the batts

 

[terra 5,000+ posts]

went to autozone and they checked everything. Alt is good, front batt is good.

 

[fbi90909 5,000+ posts]

that was quick. lol

sould be something grounding out somewhere. only thing i can think of is to check all your wires. though you already mentioned that you tightend everything down. other than that, beats me. //content.invisioncic.com/y282845/emoticons/confused.gif.e820e0216602db4765798ac39d28caa9.gif

 

[jrwalte 10+ year member]

How did they test the front bat? Did they come out and hook up a tester to it or did you remove the battery and take it inside? If the battery was still connected to the bats in your rear, they would have given the test a false reading.

 

[terra 5,000+ posts]

ya they didnt remove it so i guess thats the reading. I assume I gotta disconnect from the back to even get a good dmm reading? Everything is nice and secure. On the drive home, voltage was at 13.6

 

[jrwalte 10+ year member]

ya they didnt remove it so i guess thats the reading. I assume I gotta disconnect from the back to even get a good dmm reading? Everything is nice and secure. On the drive home, voltage was at 13.6

Yes. Remove the fuse from the positive line to the rear or just disconnect the wire from the bat and then they will be seperated from the rear bats.

 

[terra 5,000+ posts]

Yes. Remove the fuse from the positive line to the rear or just disconnect the wire from the bat and then they will be seperated from the rear bats.

ahh good idea on the fuse. thanks. I'll get the dmm out tomorrow and see what it reads. What should a solid voltage at the batt be? 12.4?

 

[jrwalte 10+ year member]

for a stock wet cell 12.2-12.4 would be right. But a good resting voltage doesn't mean a battery is in good condition. It may not hold a charge well and will quickly discharge when a load is placed on it. Auto store can test that for you.

 

[terra 5,000+ posts]

New symptom...When I turn off the car, the sub makes a low sound. it plays a low volume..30ish hz note. Goes for maybe 3 seconds. Then stops. I checked the back ground and some of the heatshrink had some off allowing the metal to touch the frame. I took it off, cleaned to ground more and then rewrapped it in elec. tape and regrounded it. Idle voltage went up to 13.4 but driving voltage wont go above 13.6. The sub still does the same thing. I have 3 back batteries. Amp has 2 grounds on the Deka and the Kinetik is the one that actually grounds to the car. Amp is the Fusion FCA4000D.

 

[terra 5,000+ posts]

Voltage is now up at 14.5. I think the back bank got drained because of the bad ground and it just needed time to recharge. however, the sub still makes a low noise when I turn it off. i can wait for like 30 seconds and then a really low frequency sound comes from it. Amp is grounded to another batt than the one that grounds to the car. That a problem?

 

[BoomBoomBoy 10+ year member]

Is your belt properly adjusted?