BIG 3 DONE, Lights still dim, and amp cuts off at 13volts?

[DammitJames 10+ year member]

Ground circuit resistance can also be checked by measuring the voltage drop across the circuit with a DVOM set on, the 2 volt scale. The voltage drop will be zero across a "good ground" circuit.

only true way to check if you have a good ground is to do a voltage drop test ohms will tell you this or that but it is not a good test for checking for a bad ground it could be fine but when you run power through it, it can still drop

put your meter on DC volts and put one lead on your amp ground then put the other lead where the amp is grounded and turn it on and play music if it reads more then 0.2DC Volts than you have a bad ground... again your putting both leads on the ground side and measuring volts... yes it sounds funny but this is the best way to check your ground... same can be done on the power side to check connections

 

[thizzkid 10+ year member]

so to measure my amp ground i would measure the tip of the cable that you would screw into the amp ground terminal, and the other side of the ground cable that would connect to the chassis ground

so in other words im just measuring the ground cable at both sides of the 3 feet cable correct?

 

[dustyshot 10+ year member]

Funny thing is that I was having really bad dimming with my setup, and all I did with out big 3, and still with stock alternator. I just bought a kinetik hc1400r battery and put it as main and my lights stopped dimming altogether. Probably won't do same for you since you are at 1200+ watts. I am at 550 RMS with 1/4 gain on my amp. That battery I got is for 1400 RMS setup, so I got more than I really need out of the battery.

 

[thizzkid 10+ year member]

i just have a regular everstart maxx battery with 1000 CCA, a walmart brand

 

[keep_hope_alive Premium Member]

so to measure my amp ground i would measure the tip of the cable that you would screw into the amp ground terminal, and the other side of the ground cable that would connect to the chassis ground
so in other words im just measuring the ground cable at both sides of the 3 feet cable correct?

that is pointless. you need to characterize the entire ground path - from ground terminal at the amp to ground terminal at the battery. you care about the path along the chassis, through connections, welds, etc. the weakest points are where you try to connect wire to metal.

refer to my earlier post.

 

[thizzkid 10+ year member]

ok so for example to measure voltage drop amongst grounds, i would put the negative DMM test lead on the ground terminal on amp with the ground connected to the amp, and the positive test lead on the negative battery terminal without connecting the terminal to the negative post on battery right??

if i do this i must get longer test leads to reach from the back of my truck to the front of the hood

 

[supermaxx123 10+ year member]

buy bigger cable and be done with it. also i would solder everything possible. 4 guage 17ft from ebay sounds to be too small. it could also be a low impedance that causes bass to cut out. amps use up a lot more power from a 4ohm load to a 2ohm load.

i once had a sub wired to 2ohms to an amp. the amp was 2ohm stable, my problem was i was testing this in a cigarette lighter(20 amp fused) The amp would cut out and the sub would too if i turned it up. ended up trying it at 8ohms and the subs was really loud compared to how loud it could be before the amp cutting out a 2ohms. and the amp didnt cut out.

 

[thizzkid 10+ year member]

well when i did my big 3 my wires were really thick 4 gauge, didnt buy from ebay, but my amp kit i bought from ebay, so im wondering if 2 gauge power wire be enough, i just need enough for the amp wire, not planning to use 2 gauge on big 3, should i be alright?

 

[supermaxx123 10+ year member]

well when i did my big 3 my wires were really thick 4 gauge, didnt buy from ebay, but my amp kit i bought from ebay, so im wondering if 2 gauge power wire be enough, i just need enough for the amp wire, not planning to use 2 gauge on big 3, should i be alright?

it wouldn't hurt. overkill may be just kill lol

 

[keep_hope_alive Premium Member]

note that some ebay amp kits use small wire with thick insulation. not all wire is created equal.

 

[keep_hope_alive Premium Member]

ok so for example to measure voltage drop amongst grounds, i would put the negative DMM test lead on the ground terminal on amp with the ground connected to the amp, and the positive test lead on the negative battery terminal without connecting the terminal to the negative post on battery right??
if i do this i must get longer test leads to reach from the back of my truck to the front of the hood

almost. refer to my earlier post regarding making a 10ohm extension and measuring that cable, so you operate your DMM within a usable range. also, you can disconnect the ground terminal from the amp and measure from that connector. definately leave the battery terminal disconnected. don't forget to remove any oxidation.

 

[thizzkid 10+ year member]

thanks guys, i will try to do some more troubleshooting today

 

[azphat12 10+ year member]

Yes you can measure your 3ft of wire to see how it performs, but the best way was described above. Test the full ground path. Personally I would test your 3ft section, if its ok move to the full path. You might just have a bad piece of wire there.

I am running 1200rms.... 800 subs / 400 comps and I ran 1/0 gauge to a distro block, and about 3ft of 4 gauge to the amps. I get minor light dimming when I am playing bass music full tilt, but other then that its fine. I have stock battery and stock alternator at 130 amps. I have only done 1 of the big 3 and that was 1/0 from battery neg to chassis.

 

[thizzkid 10+ year member]

yea same here, i get minor dimming at full tilt to, but my actual volt meter in my car dash always goes below have when the bass drops, so i get worried that my amp is going to fry from it, can that happen?

 

[thizzkid 10+ year member]

so can i get a capacitor to fix this problem aswell? i hear they arent good to use, but i also hear if i barely get light dimming isssues i should be ok, my system voltage drops only occur 3 times typically at full tilt when i play a 4 min song, those 3 times is the hook of the song, where the bass just drop excessively and thats why my dash voltmeter drops a quarter down to low when it happens

so would a capacitor and 2 gauge wiring be ok? would it cause more harm than good to my amp, and fry it?