lpchouinard

My caravan got a 140Amps factory alternator, the first question is 140 amps enough for my current setup? Second, I've got huge voltage drop when playing the system a bit loud.

What I've done:
4GA from batt to the SAE-1000D with a 100A fuse w/ground to chassis (2ft)
8GA from batt to the KS300.2 with a 60A fuse w/ground to chassis (2ft)
0GA from batt to chassis
Also, for testing purpose I tried with jumper cable the (batt to alt) and (block to chassis)

Results (SAE-1000D):
Motor on,50hz tone to the sub until the amp clip, 13.1v at batt 10.5 at amp
Motor off,50hz tone to the sub until the amp clip, 11.5v at batt 10.2 at amp
The jumper cable didn't change the results

Also, there's no voltage differential between the -batt and the chassis/block when the amp clip. I also test with a 2 farad 16v cap but this didn't help at all.

The only thing I can think of is bad ground or the 4GA is too resistive.

I need your opinion

Thanks

danyman

iTrader: (1)

im running 1000watts rms also and 140 isnt enough i find. well could be. i find that for the length of the van in 4gauge for the power is too long. i will be switching out system anyway but ill be runnin 2 runs of 1/0 to the rear.

PLUS i would change the alternator to the 160amp thats available. if you find bigger let me know man

jalat

iTrader: (6)

bump up to a higher amp fuse, like 150A for that sundown

lpchouinard

yup the 4ga is probably too small for 1000w, i just spend 120$ for that freakin wire... i'll reuse it for the front amp...

for the alt i want to fix the voltage drop first, i only found the 160amps model also but ill keep my eyes open

lpchouinard

you think a bigger fuse will be less resistive?

i could try to see if there's a voltage differential at the fuse post, good idea!

my first idea was to bypass the fuse... ill use my brain and DMM instead

lpchouinard

Hey one more thing, is it possible that i am pushing it to the max? i have a reading of 40.1v AC just b4 clipping @ 1ohm load.

is the formula V2 / R apply? bc this get 1608.1 watts(peak or RMS ?), i know there's the impedance that can change the equation.


Here's another idea, what about a 16V battery in the back only for the sundown, the kinetic HC16V is rated a 62 A/h this could give me an hour of intense playback. when i come back home i plug the charger in the ac outlet and voila! sorry, that was a brain fart...

Sasha

iTrader: (10)

If the fusing and wiring is correct, and you still get big voltage drops, look into testing that battery, as it may be bad, and not charging fully, unless it has very small capacity, and not able to buffer your system properly.

John__Taylor

iTrader: (3)

If you put a second battery in, please do not mix 12v & 16v. Seriously.

I ran 1 ought positive and neg (thanks to Yuli) to the rear batt. Yes, it was a HUGE pain to hide that.

You will also want to install a "smart" relay between the two batts. It opens to charge the aux batt when needed (13.2) and closes when it senses voltage drop on the main.

A battery isolator is another option, but more of a pain in the *** if your alt is difficult to get to, or of a certain make.

Batteries wired together have a tendency to "equalize" rather rapidly. The lower one will suck the charge from the higher one.

Also, vent your battery box if not using a gel cell or similar totally sealed battery.

Hydrogen gas:

danyman

iTrader: (1)

i have a gel cell deep cycle and i still get a drop of 1volt. get a better battery. put a proper fuse and upgrade the alternator to the 160

danyman

iTrader: (1)

and upgrade the wire to the rear to at least 2gauge 0 would be better. to pass that you might have to take out the front seat and lift the carpet to find a good spot to run that wire. the alternator is very easy to change on this van ( damn i love dodge lmao)