Voltage drop with new amp

 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 835
Registered: Oct-06
alright...i have a kx2500.1 and i just put in a optima yellow top in the trunk with a red top up front to help with the voltage drop. well it doesnt really help much. i have done the big three and i have 1/0 guage wire throughout. all grounds are good and i still get bad dimming/voltage drop. does anyone know what it could be? the alternator maybe? i will go get it tested to see if thats what it is. i mean i expected with an extra battery the voltage should only differ like .5-1 volt but im getting like 12.2 when the car is on. thats like 2 volts.it almost seems like the battery in the trunk isnt having an affect on the amp at all. all suggestions are welcomed.
 

Gold Member
Username: Carguy

Post Number: 6372
Registered: Nov-04
That's cause you still DON'T have the isolator installed. Without it, the amp will be drawing power from the starter battery as well. Therefore, the lights will dim with every beat.
Manually charge the yellowtop till it's fully charged. Then install the isolator. Now your lights won't dim as much cause the amp will only see one battery.
I strongly recommend you get HO alternator.
 

Bronze Member
Username: Chuck78

Post Number: 98
Registered: Mar-07
HO alt, the end.
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 836
Registered: Oct-06
i have a 200 amp alt. and i thought the isolator is only for when the car is off
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 837
Registered: Oct-06
and how can i manually charge the yellow top...and how will i know when its fully charged?
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 838
Registered: Oct-06
anyone?
 

Gold Member
Username: Safe_cracker

Chicago, IL US

Post Number: 3218
Registered: Jan-06
"That's cause you still DON'T have the isolator installed. Without it, the amp will be drawing power from the starter battery as well."


I am gonna have to trump you with the moron card here! Even with an isolator, where the heck do you think you are still getting the voltage from? Even with an isolator you will still get dimming, the power has to come from somewhere.... Even if the batteries are separated the isolator switch will kick in drawing power from the alt which leaves the starting battery starving. Unless you have an alt that can keep up with the demand you will always have dimming... Polo.. :-)
 

Gold Member
Username: Carguy

Post Number: 6374
Registered: Nov-04
Marco Polo, with an isolator, the power from the alternator gets split between starter and aux. Therefore, if you leave the starter for the car, and the aux for the amp, then it'll lessen the dimming. Take a dmm and try it. Measure the starter section, and the aux under current draw.
If by chance the alternator was exhausted, the starter section will still be 12.5v, whereas, the aux, could dip below 11v, depending on the amp.
And since the isolator prevents the batteries from "seeing" each other, only one will get drained.
We're talking about music here, not some power hungry inverter/spot lights/heaters etc. There's no way the amp can drain 200A alternator completely.
My post clearly stated that it "won't dim as much." Meaning there will always be some dimming.
I'd strongly suggest that you test out an isolator before expressing strong opinion.

To charge a battery manually, get a car battery charger. It should fully charge the yellowtop within 3-4 hours, and most have auto shotoff. In fact, you should do that once a month to ensure all batteries are fully charged.
 

Silver Member
Username: Tejcurrent

Post Number: 156
Registered: Apr-07
Most 200a alternators are around 130amps at idle. That kicker will be drawing much more than 130amps= voltage drop=dimming lights.
I've hooked up several batteries at once and there was much more dimming and voltage drop w/out all of them hooked up.
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 842
Registered: Oct-06
ok what is a good isolator to get? i dont know really anything about what kind or brand
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 843
Registered: Oct-06
and does anyone know where i can get like a 250 amp alt for a grand am with out getting custom mounting brackets?
 

Gold Member
Username: Carguy

Post Number: 6376
Registered: Nov-04
Look in the accessories section. You should be able to find links of HO alternator manufacturers.
For American made cars, you shouldn't have any problem.
Have you tried google? Last time I checked, I found some good links.
If your HO is 200A, then look for isolator that's rated around 150A - 170A to be safe.
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 844
Registered: Oct-06
alright thanks isaac.
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 845
Registered: Oct-06
why are there 4 places to put wires on the isolator?? (the alt, battery 1 and battery 2) what is the 4th one for??
 

Gold Member
Username: Safe_cracker

Chicago, IL US

Post Number: 3220
Registered: Jan-06
"I'd strongly suggest that you test out an isolator before expressing strong opinion."


I have and so have numerous amounts of other people. At the secondary battery an isolator will cause a 1-2V drop, this is a fact, well known at that. Nobody will recommend a capacitor even though it is impossible for one to hurt your system and nobody will recommend a isolator but this isn't because of lack of knowledge like the above. The fact is that people do know this and to suggest a person who has an already low voltage of 12.2V to add an item that eats/wastes power is not good. You need a good charging system for any of the above to work and honestly I still don't see anyone willingly adding a power drop but then again there is always that one person out there, lol. Polo.. ^^^
 

Gold Member
Username: Carguy

Post Number: 6386
Registered: Nov-04
Who are these so called "numerous amounts of other people" you're referring to? If you really have used an isolator, then you should know the exact voltage drop in your car.
My car gives 14.8v. With a .5v drop, it's around 14.3v. A battery WILL charge with 13.2v - 14.3v.
Seriously, to say "nobody will recommand a isolator" is grossly false. There are plenty of car and audio experts that DO recommend it. Have you visited your local 4x4 dealer? Look under the hood of some hobbiest with lot of "accessories" such as electric winch, power inverter, several 150w spot lights etc.
Whenever someone says an isolator drops voltage up to 2v, is giving more of an "opinion" than facts. When/if you do test one, do not try it with the cheapest one in the market. Use something that most people would likely buy.

"honestly I still don't see anyone willingly adding a power drop but then again there is always that one person out there"

That statement clearly states a biased view/opinion. That's as close minded as people blaming capacitor for all electrical power problem. As I have numerously stated in the past, an electronic item, when used PROPERLY will function as designed, NOT as "rumoured" or "wished."

I don't have time to argue on senseless points, so I strongly AGAIN, urge you to go to bcae1.com and read, read, and some more read.
Polo, just to prove that some audio experts DO use isolator, go talk to Glasswolf.

Phillp, when you purchase an isolator, it WILL come with complete easy to follow instrutions. So don't panic. The isolator has connector for battery, alternator, 2nd battery and remote. That's what you're probably asking about, the 4th connector.
 

Silver Member
Username: Holt_champ

Htown, MI

Post Number: 846
Registered: Oct-06
remote?? what remote? thanks for all of the help!
 

Gold Member
Username: Safe_cracker

Chicago, IL US

Post Number: 3236
Registered: Jan-06
"Polo, just to prove that some audio experts DO use isolator, go talk to Glasswolf."


Who is to say he is an expert? I myself have been into car audio since lets say 1985 and yes I have a degree in electrical engineering, amongst other things not related but the fact is real world proof is believing. I am in no way knocking Glasswolf because he is around the same age, he is into the same things like Auto mechanics and car audio which is some of the best hobbies you could ever mix together, BTW I am a 3rd generation grease monkey, lol. Different point of views are good and comparing 4x4 users to caraudio enthusiests is wayyy off base. Throw up a post here and on your favorite forum asking indeed who runs an isolator, not many would admit it.You need to search around, ask questions using the internet, it is a vast array of knowledge...Polo.. :-)


PS- I am in no way saying I am an expert, nore am I pretending to be but I have been around.... :-O
 

Gold Member
Username: Th3pwn3r

Post Number:...

Post Number: 4064
Registered: Jul-06
Yea...I'd rather NOT use an isolator for various reasons.Just get yourself a great alt with great wiring and a decent size batt bank and a easily viewable voltmeter and you'll never have to worry about dumping your batts so low that you can no longer start your car.So an isolator saves your starting battery right?That won't stop you from clipping the piss out of your equipment when that battery or batteries sitting in the rear drop too low on voltage.Sure you may still be able to have your starting batt but that doesn't save you from the rest of the negative things going on.
 

Gold Member
Username: Carguy

Post Number: 6388
Registered: Nov-04
Using isolator is not a popularity contest. It's about safety.
If you're as good as you claim, then you really need to learn how to express your opinions without be biased. How can you say something is plainly garbage or useless without supporting cast? To say an isolator drops your voltage 1-2v is just insane. Is that how you did your thesis in school? Degrees mean nothing if your judgment is clouded like that.
In fact that makes you sound as intelligent as those that say "capacitors are total piece of cr@p."
If that were true, then they would've never been created/designed to be part of electronics.
Isolator usage in car audio and 4x4, are the same. Different hobby, but used for the same purpose, to be able to start your car after a long day.

Just exactly what are you arguing about? What is your point? Mine was about enjoyment of music WITHOUT sacrificing safety. I have seen too many people blast away and get stranded.
I am open minded so, I'll give you a chance to enlighten me. Show me in detail as to why an isolator shouldn't be used at all. Be accurate with your statements (no opinions from "others"), just the facts. Your 1v-2v voltage drop isn't true cause I've measured it myself. I'll tell you my result once I see yours.

I'll make you a deal, if you can convince me with valid proof, and the pros outweigh the cons, then I will remove the isolator in my car. Do we have a deal?

Rob, isolator WILL save your starter battery. Your point about "clipping the piss" out of your equipment doesn't make that much sense. You can still do that with or without an isolator.
That shouldn't be your main reason for not using one.
You can add more than 1 battery to an isolator to increase the capacity.
I've also stated that the aux battery should be charged manually once a month to ensure maximum power reserve. Somehow, that part always gets dropped.

Seriously, what's more important than being able to start your car? Audio is nice, but if it kills the car, then what's the point?
 

Gold Member
Username: Th3pwn3r

Post Number:...

Post Number: 4068
Registered: Jul-06
"Your point about "clipping the piss" out of your equipment doesn't make that much sense"

If that didn't make sense to you then you truly need to research things.Yes, an Isolator will protect your starting battery.Should you ever dump your batteries so low that you don't have enough power to turn the flywheel?No.That's my point.Dumping your batts so low that you're stranded is something a true noob would do.If you know what you're doing you'll be fine.If you drop your batts so low that you can't turn the flywheel,good job,you probably just clipped the sh1t out of your sub by feeding your amplifier(s) too low of voltage.Understand what I was saying now Isaac?I never said an isolator was useless and I never said I liked or am willing to use them either.I have an onboard voltmeter that tells me what my voltage is resting at.I never see it go below 13.5 volts when my music peaks and I'm running damn near 4K rms(Without the vehicles normal/practical accessories).I have a 300 amp alt,2 runs of pos to the rear,3 grounds in the back(1 per HC2400 and a ground for the amps(all separate runs) also I have my big 3 done.Do I need an isolator?Nope.I'll never drop my voltage low enough or my batts to need one period.I also have a large enough battery bank to run with the system off and I can watch my levels on my voltmeter so...I'd have to be a real moron to get stranded.
 

Gold Member
Username: Carguy

Post Number: 6392
Registered: Nov-04
Rob, I don't think I was referring to you when I said "isolator was useless."
In your setup, it's not required cause of 300A alternator.
The problem with lot of "others" is that, they get caught up in the music and forget to monitor the battery level. Then, when it's time to go, the car won't start/shuts down at idle.

I'm all about safety, so I preach that philosophy.
You can never be too safe.
 

Gold Member
Username: Th3pwn3r

Post Number:...

Post Number: 4072
Registered: Jul-06
For 25 bucks you can get yourself a nice looking voltmeter and know exactly what your system is doing.That provides a hell of a lot of confidence that things are at safe levels as you talked about Isaac.I always try to recommend that people get voltmeters and hook directly to the amplifier.This way you'll know what voltage your amplifier is seeing and if you have a break in your power line somewhere you would still know.Some people hook them to their battery in the front but then they're running a 15+ foot wire in their vehicle and wouldn't even know if it came loose from their battery(s) in the rear.Also...guys you really shouldn't run your systems with the engine off unless your at comps.If you get stranded at a comp it's no big deal,someone will be able to jump start you back up.You should never let your voltage get that low in the first place though,I can't stress that enough because you can damage quite a few pieces of equipment by feeding insufficient voltage to your electronics.
 

Gold Member
Username: Carguy

Post Number: 6394
Registered: Nov-04
Rob, voltmeters are great, if it's used properly. However, that alone will not always be accurate. A defective/dying battery can have 12.5v reading, but can drop significantly whan a load is applied. Just keep that in mind.
 

Gold Member
Username: Juliob

Santo DomingoDominican Re...

Post Number: 4828
Registered: Dec-05
nice thread
 

Gold Member
Username: Th3pwn3r

Post Number:...

Post Number: 4105
Registered: Jul-06
I try keeping things a debate and not an argument :-)
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