MazzaSEC Build log! Sundown, Fi, Deka, PG RSDS

[mazzasec 5,000+ posts]

Ya but with 3 **** batteries and a 250 amp alt why am i still dropping into the high 11's

 

[MikeyB 5,000+ posts]

Remains a mystery to me man lol.

Big 3 in 1/0, power and ground run to the back, ground the battery bank at the rear as well, maybe add another alt to front batt run. If youve got another batt around try hooking it up back there as well.

I mean, whats your voltage when your ramping up the rpm's? Without any draw?

At 2000rpm you really shouldnt drop below 13.9 imo.

 

[mazzasec 5,000+ posts]

No draw at IDLE when I first start the car after its been sitting in the garage it idles at 14.65. It idles 14.4 all day long.

 

[MikeyB 5,000+ posts]

Well thats how it should be man, all thats sayings is your dont have the amperage in the rest of the system to keep up with the draw. I say add a batt if you have one.

You have both a pos and neg run front to back right?

 

[mazzasec 5,000+ posts]

Well thats how it should be man, all thats sayings is your dont have the amperage in the rest of the system to keep up with the draw. I say add a batt if you have one.
You have both a pos and neg run front to back right?

Not now. But when I had the extra wire I did that. Didnt help anything....

 

[king ranch 5,000+ posts]

maybe try 2 runs of 1/0 from alt to pos battery, not sure if u have tried that yet but can just one run of 1/0 handle and supply that much power to keep up with the draw

 

[MikeyB 5,000+ posts]

Man my guess is your just getting choked off with your wire. According to a couple calculators I punched the numbers through....

20ft 1/0 wire, ~3800watts, 60% efficiency (these specs arent exact I just didnt feel like digging around), from 14.4volts.....

=0.872volt drop, now thats not near what your seeing, but thats about 440amps of draw, through a wire that can handle 250amps of current.

At 70% efficiency still 377amps.

Thats just an idea of what could be happenings and all those numbers get worse as your charging voltage falls.

What you can try and do is run another pos and neg run from the front batt, to the rear bank. If that doesnt solve the problem I dont know what will. //content.invisioncic.com/y282845/emoticons/crap.gif.7f4dd41e3e9b23fbd170a1ee6f65cecc.gif

 

[mazzasec 5,000+ posts]

I mean is my Sundown amp pulling THAT much amperage at .5? How much of a difference would it make on my voltage running it at 1ohm.?

 

[MikeyB 5,000+ posts]

maybe try 2 runs of 1/0 from alt to pos battery, not sure if u have tried that yet but can just one run of 1/0 handle and supply that much power to keep up with the draw

The alt run should be fine. If the length is as short as an alt run would be....

Im almost stumped man //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif

edit- A 5ft run of 1/0 can flow almost 1000amps according to my source

 

[king ranch 5,000+ posts]

try it at 1ohm and see wat u get

 

[mazzasec 5,000+ posts]

I cant I only have d2 subs. Its just wierd cause before I was running 2 1500d's at .5 stock alt and 1 1400 under the hood and 1 2400 in the rear and was dropping to 11.7 with STOCK alt and 2 Batteries. Now with a 250 amp alt and like 4 batteries I gained .2 of a volt...

 

[MikeyB 5,000+ posts]

I mean is my Sundown amp pulling THAT much amperage at .5? How much of a difference would it make on my voltage running it at 1ohm.?

Ive seen the specs but I cant recall them exactly. I mean, if your charging around 14 volts, and are seeing ~3800 watts from it, then you could see minimum, ~270amps, and thats 100% efficiency, which is not happening at all, especially at .5.

At 65% your looking at 406amps //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif according to the numbers Im seeing.

 

[MikeyB 5,000+ posts]

I cant I only have d2 subs. Its just wierd cause before I was running 2 1500d's at .5 stock alt and 1 1400 under the hood and 1 2400 in the rear and was dropping to 11.7 with STOCK alt and 2 Batteries. Now with a 250 amp alt and like 4 batteries I gained .2 of a volt...

Dig up some of the info on them. Ive read over the measured specs of a strapped pair of 1500's against a 3000 a few times. I know its out there.

Either way thats weird. Keep in mind though, you have lots of current on tap at the batts, the alt is just maintaining that power.

Are you measuring the drop at the front batt or rear bank?

 

[mazzasec 5,000+ posts]

Ive seen the specs but I cant recall them exactly. I mean, if your charging around 14 volts, and are seeing ~3800 watts from it, then you could see minimum, ~270amps, and thats 100% efficiency, which is not happening at all, especially at .5.
At 65% your looking at 406amps //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif according to the numbers Im seeing.

What would cause a full 406amp draw though? With the frequency changing I am sure its not likely to happen on just music.

 

[mazzasec 5,000+ posts]

I am measuring the drop at the amp. Reads 11.8 Front battery reads like 12.4