Need advice with electrical please.


TrippyManeRob

CarAudio.com Newbie
Jul 20, 2021
4
0
Michigan
Ok so I recently installed a 250 amp H. O alternator in my car and when I installed it all I had was some 4 guage wire laying around so I used that for the positive to the battery.. My car is a Volkswagen and it took me 2.5 hours to remove the alternator and around the same to re-install it.. Clearly it should have a 0 guage power wire so i ordered some and instead of taking the alternator out again I just left about 2 feet of 4 guage and put a fuse on it and ran the rest as 0 guage. ( I have also done the big 3 in 0 guage aswell.) So now lets get to my problem.

If i run my 1500 watt rms Memphis PRXA @ 4 ohms (750 rms) to my 2 12" Alpine type r's (4 ohm DVC) I have zero voltage drop issues at all. But if I run my amp full tilt @ 1500 rms witch is 1 ohm then I get bad voltage drop and I dont get enough power to satisfy my subs without clipping or the amp going into protect for a brief second.

I know if i dont figure this out im going to fry my subs so I just have them running at 4 ohms until I can solve my issue...

So do you guys think I could possibly have a shitty ground problem or do you think that chunk of 4 guage on the alternator could be my problem? I have a brand new agm battery under the hood and I have an extra regular lead battery sitting here that I could put in my trunk if you think that could help my voltage drop... Any advice would be HIGHLY apprrciated, I just wanna be able to slam my subs the way they were intended and i feel deafeated lol. Thank you in advance.
 

Popwarhomie

Team Lethal Pressure
5,000+ posts
10+ year member
Jan 22, 2010
9,795
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FL
Is this a name brand 250 amp alt or an ebay special?

2' of 4 gauge OFC should be fine but I would deff replace it with 1/0.

Why not just run at 1 ohm and turn the gain down instead of rewiring to 4 ohms until you figure out your voltage issue?

Don't put a vented lead acid inside a vehicle. If it's a sealed lead acid you can.

Check your ground with a multi meter.
 

TrippyManeRob

CarAudio.com Newbie
Jul 20, 2021
4
0
Michigan
  • Thread Starter Thread Starter
  • #3
Is this a name brand 250 amp alt or an ebay special?

2' of 4 gauge OFC should be fine but I would deff replace it with 1/0.

Why not just run at 1 ohm and turn the gain down instead of rewiring to 4 ohms until you figure out your voltage issue?

Don't put a vented lead acid inside a vehicle. If it's a sealed lead acid you can.

Check your ground with a multi meter.
Is this a name brand 250 amp alt or an ebay special?

2' of 4 gauge OFC should be fine but I would deff replace it with 1/0.

Why not just run at 1 ohm and turn the gain down instead of rewiring to 4 ohms until you figure out your voltage issue?

Don't put a vented lead acid inside a vehicle. If it's a sealed lead acid you can.

Check your ground with a multi meter.
I re did all my grounds and my subs stopped clipping and can run them at almost full tilt at 1 ohm now so thats cool... Headlights still dim a bit but hoping once i get rid of that 4 guage chunk that will help seeing as how. Its only rated for 150 amps and my alternator is 250 amps
 

Coolhand20th

CarAudio.com Elite VIP
Mar 27, 2019
1,621
464
nowhere
Yes but what brand of alternator? Not all alternators are the same. Hence why he asked if it was one of those eBay specials. Those are known to be well not all that good putting it nicely.
 

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