1. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by mat3833
if you have a DMM do this for me:

run a wire from the battery ground to where your trunk ground is. measure the resistance of that peice of wire and write that number down. now take that wire and your DMM. put the + probe on the ground in your trunk and the - side on the wire, read the resistance. if the second number is any more than .1 higher(honestly you should aim for .01 if your DMM reads that low) you have a ****** ground.

Matt
Does it have to be a 4ga or 0ga wire?. Cuz if it does that aint gonna happen because i don't have 20ft of any power/ground wire. I dont think i have 20ft of ANY wire atm.

2. ## Re: Massive voltage drop at amp but not at battery? Help

Let me get this straight, OP is running a 3K amp off of stock electrical and we're debating wire gauge as a cause of voltage drop?

3. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by gamehawk55
Does it have to be a 4ga or 0ga wire?. Cuz if it does that aint gonna happen because i don't have 20ft of any power/ground wire. I dont think i have 20ft of ANY wire atm.
i use 12 ga for the test. doesnt matter what kind of wire you use, just make sure to measure the resistance of it before you do the test.

Originally Posted by hispls
Let me get this straight, OP is running a 3K amp off of stock electrical and we're debating wire gauge as a cause of voltage drop?
NO. obvioisly you havent read a **** thing, his voltage is dropping ONLY at the amps. not the battery. this means something isnt right, either a bad connection or ground or something. im trying to walk him through a few ways to find out if his grounds are solid as well as eliminating the distro as a problem.

Matt

4. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by mat3833
i use 12 ga for the test. doesnt matter what kind of wire you use, just make sure to measure the resistance of it before you do the test.

NO. obvioisly you havent read a **** thing, his voltage is dropping ONLY at the amps. not the battery. this means something isnt right, either a bad connection or ground or something. im trying to walk him through a few ways to find out if his grounds are solid as well as eliminating the distro as a problem.

Matt
Well I haven't been able to do the wire test yet because I'm working but I was able to check the resistance of the grounds up front and in the rear and all read 0.2-0.3ohms resistance which would suggest that the grounds are good. And the amp GETS the same voltage as what is read up front. Minus like a tenth of a volt due to slight resistance in the line. So if I read 14.1v at the alt or battery the amp will read about 14.04 or spmething. But it's when it's playing that the voltage can drop drastically at the amp. Maybe I'll try to get a video of it.

5. ## Re: Massive voltage drop at amp but not at battery? Help

might be the distro then.

Matt

6. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by mat3833
i use 12 ga for the test. doesnt matter what kind of wire you use, just make sure to measure the resistance of it before you do the test.

NO. obvioisly you havent read a **** thing, his voltage is dropping ONLY at the amps. not the battery. this means something isnt right, either a bad connection or ground or something. im trying to walk him through a few ways to find out if his grounds are solid as well as eliminating the distro as a problem.

Matt
I guess, I'm missing something. So what amp, how big is the alternator and how many extra batteries?

7. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by mat3833
might be the distro then.

Matt
Ok here's the video. It's not quite a 2v difference but it's still quite a large variation and the voltage is holding much stronger at the battery.

https://db.tt/rG1QAJP0

8. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by hispls
I guess, I'm missing something. So what amp, how big is the alternator and how many extra batteries?
never bothered to ask because the voltage at the battery stays where it should. ive never seen the battery stay at 13.6 and the amp drop to sub-11V sue to too much current draw. ive seen battery AND amp voltage drop due to that tho. and the info is in his sig. big 3 in 0ga. 0ga run to the back. RF 2500.1 BDCP and an AQ 200.2 no extra batts are listed. and hes at 2 ohms, so current draw shouldnt be that high unless hes clipping the **** out of the signal. but even then battery voltage would drop too.

Matt

9. ## Re: Massive voltage drop at amp but not at battery? Help

Also I will mention that the amp is only tuned to put amount approx. 1000w to the subs. NOT the full 3600w this amp is capable of. I'm not an idiot lol. If I ran 3600w to those 8s I would blow them right out of the basket in their current box. Not to mention completely fry my electrical system in about 30 seconds haha

10. ## Re: Massive voltage drop at amp but not at battery? Help

OK, I guess it must be something other than trying to run 3K amp on stock electrical. Keep changing grounds and distro blocks and adding more 1/0 gauge, I'm sure that'll sort you right out. I'm done here.

11. ## Re: Massive voltage drop at amp but not at battery? Help

can you not read? he is running 1K on stock electrical his car has a 120+ amp alt. having voltage issues ONLY at the amp and not at the battery/alt means something is wrong from the battery to the amp or the amp to the ground. hell it could be something entirely diferent. but running 1K on a 120A alt with the big three and 0ga is NOT an issue man. are you smoking crack? if he was running at 1 ohm yea, sure its the amp drawing too much current. but running at 2 ohms he should have no issues at all.

Matt

12. ## Re: Massive voltage drop at amp but not at battery? Help

Have you metered the same voltage drop on both sides of the distro?
i.e. in / out?

13. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by azmcrae
Have you metered the same voltage drop on both sides of the distro?
i.e. in / out?
didnt think of that. good idea. if its not the distro and all the connections at the amp are secure idk what it could be.

Matt

14. ## Re: Massive voltage drop at amp but not at battery? Help

Also, do you have a fuse or circuit breaker up front near the battery?
Check both sides of it if you do.

I have seen this same problem several times back when I had my car audio shop.

15. ## Re: Massive voltage drop at amp but not at battery? Help

Originally Posted by azmcrae
Also, do you have a fuse or circuit breaker up front near the battery?
Check both sides of it if you do.

I have seen this same problem several times back when I had my car audio shop.
I have a 250A ANL Fuse up front within about 8 inches of the battery.

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