where to start with voltage drops?

[GiganticPrune 10+ year member]

so in my wrx, i have a yellowtop to replace the stock battery under the hood, a kinetik 1400 in the trunk, a 185 amp alt (does i think 160 at idle) and big 3 done.

now i used the yellowtop from my previous car, its about 2 years old. i bought the alt used, and i bought the kinetik used from a guy running 2 zx2500.1's off of stock alt and like 3 batteries.

i have my zx2500.1 running at 2 ohms, but i get really really bad voltage drops. where do i start in finding out where my problem is? bad batteries? bad alt?

now when i was hooking up my HO alt, the manufacturer (powermaster) says to hook this random wire up to a 12 volt ignition on source, i was a bit lazy and just hooked it up straight to the battery. i drive all the time so i wasnt concerned of it draining the batteries...

Click to read more...

 

[dman4486 5,000+ posts]

let the vehicle sit overnight and see what the resting voltage is on them. I think your laziness may have the alt doing extra duty every day to try and recharge the batts.

 

[GiganticPrune 10+ year member]

so i tested this morning after letting it sit overnight. the yellow top in the front read 12.2, the kinetik in the back read 12.65.

so..is that telling me anythign?

 

[audiolife 5,000+ posts]

if the batteries are taking a charge they would rest at around 12.8 volts

 

[GiganticPrune 10+ year member]

So basically my alt is straining to charge 2 bad batteries? Grr.

 

[audiolife 5,000+ posts]

So basically my alt is straining to charge 2 bad batteries? Grr.

sounds like its not charging anything....

 

[GiganticPrune 10+ year member]

So....does that seem like the alternator or the batteries are to blame?

 

[DBBOOM 10+ year member]

now when i was hooking up my HO alt, the manufacturer (powermaster) says to hook this random wire up to a 12 volt ignition on source, i was a bit lazy and just hooked it up straight to the battery. i drive all the time so i wasnt concerned of it draining the batteries...

So you have the exciter-circuit wire hooked up constant:crap:. The wire is supposed to be connected through a switched 12v source.

 

[GiganticPrune 10+ year member]

So you think that is making a huge difference?

That was gonna be my next step after making sure my grounds were as clean as they could be