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No voltage drop anymore?


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My voltage would drop from 14.8 to almost 11.8 if I hammer the volume for about 5 minutes with solid bass notes, let it up and voltage was right back up. This was with stock 105a alternator, big 4, 2 batteries in back. I noticed that the ground from my main battery to the chassis had come undone ( used shit solder) and just by moving it no more voltage drop, like barely .3 volt. A few hours ago I put an alternator from a 04 Tahoe ( 140amp) in it and had to move my ground on the alternator and replaced bad battery to chassis ground. I still get a bit of dimming on my gauge cluster but almost no voltage drop even pounding on the bass. I charged my.main battery last nite also, but I do that maybe once a week since I don't drive very far daily. I usually just charge main with everything still hooked up, tonite I pulled main fuse and hooked charger to rear battery side of fuse block just to have piece of mind it's charging just rear batteries.  Another thing that baffles me is I get 14.4 v at alternator and main battery terminal, but at either side.of my main fuse I get 12.3 v, same at rear batteries, but if I pull main fuse the front side has 14.4 and rear side has 12.3. Left me scratching my head.  All my fuses are good so why don't I have 14.4 at my Rea batteries? My volt meter is hooked to the cigarette lighter power as of right now. Gonna get another volt meter hooked just to rear batteries so I can read at both sides at the same time. Sorry to ramble,  just alot of info to put out there..going to be gutting and redoing the rear of.my.blazer soon and run 2 runs of 0 along frame rail and up through the floor when I redo it so I can run everything else nice and flat across floor of vehicle without lumps.

2009 Silverado 1500, 7.5" lift, 37x12.50r17s, Built Gen 4 5.3L ( 4.8l flat pistons, decked 243s, SS2 Cam, Pac 1218 springs, ported intake, 120mm TB, Long tubes, 3" duals HP tuner software tuned by me), 4l80e swapped and 4.56 gears. All done by me. stereo is Pioneer avh 600ex, all stinger rca, jp23 v1.5, skar rp150.4, and hertz hpd4. 2 SHCA 6.5 8ohm, 1 SHCA 3.5", and 1 DS18 tw120pro in each door. The 3.5 mid and 3.5" tweeters are powered by the skar rp150.4, the 6.5s are powered by the hertz bridged @4 ohms. Dual runs   of 3/0 welding cable, 300a alternator, 2 Vmax AGMs up front. current sub is a AB XR 12 ( dual 2 ohm) with bottom spider cut out in 2.25 cubes at 32hz

 

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Also, don't really trust my volt meter, but when I got it I put it in parallel with my snap on multimeter and it was dead on and almost as quick as my snap on was so some.credit was due...Maybe I broke it? I just cannot believe a 105 amp alt can keep up with 2700 watts rms and not get a volt or 2 drop with heavy bass.

2009 Silverado 1500, 7.5" lift, 37x12.50r17s, Built Gen 4 5.3L ( 4.8l flat pistons, decked 243s, SS2 Cam, Pac 1218 springs, ported intake, 120mm TB, Long tubes, 3" duals HP tuner software tuned by me), 4l80e swapped and 4.56 gears. All done by me. stereo is Pioneer avh 600ex, all stinger rca, jp23 v1.5, skar rp150.4, and hertz hpd4. 2 SHCA 6.5 8ohm, 1 SHCA 3.5", and 1 DS18 tw120pro in each door. The 3.5 mid and 3.5" tweeters are powered by the skar rp150.4, the 6.5s are powered by the hertz bridged @4 ohms. Dual runs   of 3/0 welding cable, 300a alternator, 2 Vmax AGMs up front. current sub is a AB XR 12 ( dual 2 ohm) with bottom spider cut out in 2.25 cubes at 32hz

 

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Because your reading voltage through the cars acc/ign wire, a bad connection from front to rear would likely "show" less voltage drop on the meter unless you were reading it directly off the rear bank.  The less current that travels to the rear bank, the higher your voltage will show up front. 

Bad connection at the front battery? Your (ign/acc) meter would show more voltage drop during a heavy session due to more resistance and less total current.

I stick with copper lugs torched with solder, under the engine bay is pretty harsh. Gets hot/cold/humid/dry ect ect, the quality of the cable and connections will minimize these problems.

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Found issue, was a bad ground on rear battery bank, was no volt drop on main meter because rear batteries were taking all the load. Basically the bad ground isolated my amps from the cars electrical system. Cause of bad ground was bunk solder on the ring terminal. Started checking all my wires and found a few more discolored soldered rings. So I just ordered 50' skyhigh 1/0 and 50 copper lugs and a hexagonal crimper, going to redo all my power wires and have enough to double run everything. Cca doesn't solder well or didn't like the solder I used so not going to solder again, just 8 ton crimp everything and call it done. FYI, fixed the ground and normal voltage drop came back so am positive the solder joint was the issue.

2009 Silverado 1500, 7.5" lift, 37x12.50r17s, Built Gen 4 5.3L ( 4.8l flat pistons, decked 243s, SS2 Cam, Pac 1218 springs, ported intake, 120mm TB, Long tubes, 3" duals HP tuner software tuned by me), 4l80e swapped and 4.56 gears. All done by me. stereo is Pioneer avh 600ex, all stinger rca, jp23 v1.5, skar rp150.4, and hertz hpd4. 2 SHCA 6.5 8ohm, 1 SHCA 3.5", and 1 DS18 tw120pro in each door. The 3.5 mid and 3.5" tweeters are powered by the skar rp150.4, the 6.5s are powered by the hertz bridged @4 ohms. Dual runs   of 3/0 welding cable, 300a alternator, 2 Vmax AGMs up front. current sub is a AB XR 12 ( dual 2 ohm) with bottom spider cut out in 2.25 cubes at 32hz

 

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On 12/30/2018 at 5:31 PM, ehall8702 said:

Found issue, was a bad ground on rear battery bank, was no volt drop on main meter because rear batteries were taking all the load. Basically the bad ground isolated my amps from the cars electrical system. Cause of bad ground was bunk solder on the ring terminal. Started checking all my wires and found a few more discolored soldered rings. So I just ordered 50' skyhigh 1/0 and 50 copper lugs and a hexagonal crimper, going to redo all my power wires and have enough to double run everything. Cca doesn't solder well or didn't like the solder I used so not going to solder again, just 8 ton crimp everything and call it done. FYI, fixed the ground and normal voltage drop came back so am positive the solder joint was the issue.

Nice mate, i was gonna buy the same crimper, the videos iv seen show it works pretty damn good for only 50 bucks.  Turns the wires inside the lugs into a solid piece of metal. 

Sundown NSV4 18"  +  Sundown SALT-4 Baby

MechMan Elite 370a  +  XS3100 - XP3000

SHCA 1/0 OFC(blue+  SMD Fuse Holders(blue)

Pioneer AVH-2440NEX  SHCA Pro RCA 

 

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