Quick question on electrical

[Bobby322 10+ year member]

I've got a sprinter 100ah (65lbs) underhood, Big 3 in 1/0, 2 runs of power and 2 grounds, and a 134ah (or 120ah forgot..100lbs) in the back. I dont have a separate ground for the back- do I need to add one even though I have the ground runs from the front? Also what is the max length a ground run TO the amp can be? I'm thinking either:

a. the amp is hella powerful and I need a new alt

b. I need to add the ground

c. the amp ground needs to be shorter.

Thinking its A or B since it is a prototype //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

Click to read more...

 

[Bobby322 10+ year member]

added the ground and I think it helped quite a bit, but I think my HU may need to go. Its an apline 9884 that ive had for a few years. 2v pre outs I think, and I just pulled it out and the back of it was really hot to the touch. My rcas are pretty old too.

 

[fasfocus00 5,000+ posts]

something I do for systems with power greater than 2k watts is make a ground run from the battery to the grounding point in the back. some will tell you, that you don't need to have a grounding point other will tell you it is a must. if you complete the electrical circle, you're fine

 

[Bobby322 10+ year member]

I just added a ground to the back battery and I think it helped quite a bit. I sanded an area on the frame for the initial ground, and then from that ground I ran another wire to the chassis on the outside. Think my HU may need to go. 2v preouts and I just took it out and it was really hot to the touch on the back.

 

[Bobby322 10+ year member]

Pretty sure my HU is the problem, its only 2v preouts. It's not my electrical, subs, or amp because its been like this with every system I've had. I have to turn the gain up pretty far (3/4) and the volume up to around 18-22 for it to start hitting hard. Otherwise the bass is almost non existent. This would cause clipping which is whats up with my electrical. This sound right?

 

[hatedonmostly 5,000+ posts]

I told you previously that you'd be better off with a HU with higher preouts.

 

[Bobby322 10+ year member]

I told you previously that you'd be better off with a HU with higher preouts.

Guess you were right lol...you think thats the problem? Will get a 4-5v HU next. Bass boost is off and bass settings on HU are 0

 

[hatedonmostly 5,000+ posts]

It will help with clipping...pretty much any HU/anything electrical is gonna get warm/hot over time though...

What's your problem exactly? I was looking for it and only see you mentioning clipping being an issue in post five...

 

[hatedonmostly 5,000+ posts]

It will help with clipping...pretty much any HU/anything electrical is gonna get warm/hot over time though...

What's your problem exactly? I was looking for it and only see you mentioning clipping being an issue in post five...

 

[Bobby322 10+ year member]

My voltage is dropping pretty bad, and ive ran 2k+ amps before and it wasnt this bad. Either:

a. amp is way underrated at 2k (its a new dc prototype)

b. HU is screwing everything up

Def. not my batteries, wiring, amp, or sub causing any problems. Everything is basically new..ive had this problem before with my systems - where you have to turn the gain up too high for it to hit like it should be.

 

[hatedonmostly 5,000+ posts]

I don't think the voltage issue and the gain setting are related, I think the amp is just drawing more current than your electrical is used to.

 

[Bobby322 10+ year member]

Ive ran an AQ2200 and a db drive pt2000 and it didn't do this. And that was with my stock underhood battery and 1 power run.

If I turn the gain down I get really weak output.

 

[hatedonmostly 5,000+ posts]

Why would an electrical issue be caused by the HU?

 

[Bobby322 10+ year member]

I was thinking that the low voltage preouts on the HU make my turn the gain up to compensate

 

[WheresTheButta 10+ year member]

I was thinking that the low voltage preouts on the HU make my turn the gain up to compensate

that's not how it works. How much current your amp sucks has nothing to do with what voltage your rcas are. The only relevant thing is how much power the amplifier is taking in order to generate the final output.

let me edit to explain this -

say you have an amplifier that is putting out an honest-to-God 2,000 watts (clamped). The formula we'll use is amps times volts = watts. If the amplifier is 100% efficient, it will take 166.66 amps of current at 12 volts to produce 2,000 watts. Your amp will **** 166.66 amps at 100% efficiency.

Now, say you have a new amp, which is producing 2,500 watts (clamped) , but you have a voltage drop to 11 volts, and your efficiency is 90%....

2,500= (11 times Xamps) * 0.9 and you'll see that you're now drawing 252.52 amps of current!!!!