im now convinced batcap 2000 can't handle..

[Redlineaudio 10+ year member]

You want a batt with a deep reserve up front measure the hole and put in as big as you can.

Also an Alt will degrade over time and not put out full power, even thought it does work.

 

[azbass 5,000+ posts]

alternator

 

[jco1385 5,000+ posts]

Ok chase007 please let this one go we have this one thank you..

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[loopkiller 10+ year member]

yes all the time. however, for a long time this week I drove around with no music. I am certain these batteries are charged up good.

They should be fully charged after a week of rolling sans music. No doubt.

pulling current through wire in itself causes voltage drop....something most people seem to not understand...say all your wiring and connections etc has a total resistance of .01ohms...if you try to pull 200 amps through that, right off the bat you are going to have a 2v drop, even if you had an infinite power supply.
if your voltage immediately jumps back up after bass stops, it means your voltage drops are only because of resistance, not overdraw, or it could mean that you are overdrawing but you have a shit ton of charging supply, which you don't.

What you are saying would make sense if his batteries were far away, but he has a Batcap 2000, which per Ray @ Batcap says can handle 2000W RMS no problem, very close to those amps. Since the battery is right there, and it is rated to handle well above his load, there should not be these large voltage drops. The battery should hold above 12.0V even without alt power.

holding 11 volts with 30 seconds of full tilt with car off is normal or slightly better than normal
i would do all testing with car running

Sorry, I have to disagree here. With good batteries, he should stay well north of 12.0V, even with the car off.

thats about right with a stock alt

I have a 70A stock alt, HC1400 under the hood, about 1000W RMS, and have minor fluctuations in voltage. Idle no load my alt puts out 14.4V and under heavy punchy bass, I see drops to 13.8V at the very most. I do not even have a rear battery.

I dont really understand all the advice being given to this guy.
First of all, if you are playing music loud, with your car off, your voltage is going to drop considerably. Dropping to 11V on 30 seconds of loud music with the car off is very good IMO.

Second of all, some cars charge very little at idle. I know in my gf's car, voltage sits around 12.8 at idle, but depending on here speed, can be anywhere from 12.8-14.0. (The alternator is not faulty, that's just how the car is designed. It's a 2008 Yaris.) His alt probably charges very little at idle as well. If you are having voltage drops with the car running, and you have a decent battery and the big 3 done, just upgrade your alt and you should be set. Make sure to get one that does some decent power at idle if you are going to be jamming while idling.

I play loud music with my car off all the time in the summer. I have never found my battery resting at less than 12.0V, even after playing music for hours. I am sure if I played test tones for a full hour, I would see much different results.

 

[Buck 5,000+ posts]

It will easily handle that system if your charging it back up and you don't have a bad battery.

 

[loopkiller 10+ year member]

It will easily handle that system if your charging it back up and you don't have a bad battery.

Well pilgrim, it ain't cutting it. He has had it charged and load tested and it is coming back as full and good. The dang thing just ain't getting the job done.

 

[Rashaddd 5,000+ posts]

What you are saying would make sense if his batteries were far away, but he has a Batcap 2000, which per Ray @ Batcap says can handle 2000W RMS no problem, very close to those amps. Since the battery is right there, and it is rated to handle well above his load, there should not be these large voltage drops. The battery should hold above 12.0V even without alt power.

I have a pair of batcaps sitting within 2 or 3 feet of my amp, running 1500 rms. If I measure voltage at the batteries playing a test tone full tilt, it drops to about 12.6 after about 15 seconds. At the amp, it drops into 11's...the difference? The wire and connections.

Edit: Which aren't very good and I need to fix them but I can't be bothered because I'm taking it all out soon anyway...

 

[Buck 5,000+ posts]

Well pilgrim, it ain't cutting it. He has had it charged and load tested and it is coming back as full and good. The dang thing just ain't getting the job done.

Bullshit I don't dim with my 9.1 unless I crank it up all the way. I mean I did burps with my 9.1 and my voltage would drop to like 13 or so. But regardless a no battery is going to be good enough without something to charge it. And if he is riding around full blast all the time, the alt is not going to be able to produce as much current as he's pulling. I would get an h/o alt before saying the batcap isn't working. No matter what battery you put in there, if it isn't be charged as much as it's being used, it won't get the job done.

 

[natisfynest 10+ year member]

All lies. Dude you're so full of shit your eyes are brown. Either that or you have a whole car full of FIAL. I believe it's both. Stick to computers.

**** that he sucks at computers too

 

[vandiar2 10+ year member]

I have a pair of batcaps sitting within 2 or 3 feet of my amp, running 1500 rms. If I measure voltage at the batteries playing a test tone full tilt, it drops to about 12.6 after about 15 seconds. At the amp, it drops into 11's...the difference? The wire and connections.
Edit: Which aren't very good and I need to fix them but I can't be bothered because I'm taking it all out soon anyway...

I have knu 1/0 from front to back pos and neg. 1/0 welding wire on the big 3. I guess I don't understand exactly what you are telling me. I have checked all of my fuse holders, made sure everything was snug. I am lost no doubt. now, the guy that was talking about being having low voltage at idle. The car I am driving is a manual. at high rpm's going, my lights still dim.

 

[Buck 5,000+ posts]

I have a 70A stock alt, HC1400 under the hood, about 1000W RMS, and have minor fluctuations in voltage. Idle no load my alt puts out 14.4V and under heavy punchy bass, I see drops to 13.8V at the very most. I do not even have a rear battery.

Ok.....1000w rms means you're pulling what, 100A at most? The 1500 he's using has 160A fuse rating. They are efficient, but if he has a 70 amp alt too, there's a 60 amp difference between what both of ya'll are pulling.

 

[Rashaddd 5,000+ posts]

I have knu 1/0 from front to back pos and neg. 1/0 welding wire on the big 3. I guess I don't understand exactly what you are telling me. I have checked all of my fuse holders, made sure everything was snug. I am lost no doubt. now, the guy that was talking about being having low voltage at idle. The car I am driving is a manual. at high rpm's going, my lights still dim.

do you have an accurate dmm by any chance? Like that can measure resistance out to 1/100th or at least 1/10th of an ohm?

 

[vandiar2 10+ year member]

do you have an accurate dmm by any chance? Like that can measure resistance out to 1/100th or at least 1/10th of an ohm?

I would say so yes, it measures milliohms.

 

[vandiar2 10+ year member]

Ok.....1000w rms means you're pulling what, 100A at most? The 1500 he's using has 160A fuse rating. They are efficient, but if he has a 70 amp alt too, there's a 60 amp difference between what both of ya'll are pulling.

I have a 90 amp alt.

 

[Rashaddd 5,000+ posts]

I would say so yes, it measures milliohms.

take one lead to the positive terminal on the battery, one lead to the positive amp input, what does it read? should be very small, like .005 ohms or somethin