4rx

My old stock alternator and high output alternator metered same voltage 13.9-14.0volts. Is the ecu controlling the voltage? I would like to raise the voltage to 14.8volts. Anyone know how to do it? I have three aftermarket batteries that is good up to 14.9volts(15.1v max). The reason I want to raise the voltage is because the amp will do more power with higher voltage. Is there an externally adjustable regulator voltage somewhere?

Thanks in advance,
4rx

nv4runner

To put it simply, alternators are all regulated by a circuit of some sort, either inside the alt or outside such as by the PCM. The typical automotive battery is fully charged at 12.6 volts, but to get there you have to have a source with a higher voltage. That's why alternators typically charge between 13 and 15 volts. How high the voltage is depends on how full the battery is. The higher the battery charge the higher the voltage needed to recharge it. The regulator stops the charging once the battery is full. Otherwise the battery would overheat and deteriorate until it was a mass of lead, plastic, and sulfuric acid that isn't capable of storing electricity.

The difference between your stock alt and your high output alt is how many amps it can produce. When you try to exceed the alternator's maximum amperage output by running too many accessories the voltage will drop because it simply can't produce what your are asking of it. That's where the high output alt is needed. It has the ability to produce more amperage to support all of the additional accessories for the 12 volt system.

To answer the question, you would need to find or make a step up transformer to bump up the voltage to just your amp without causing other mischief with the rest of the vehicle's system. Most people install large capacitors in parallel with the amp to supply additional amperage when the deep bass hits, but they all are still running on normal charging system voltage.

xskydivingdudex

Hmm thats weird bc my battery indicator says mine is at 14.4 with subs off and 14.8 with subs on.

BajaRunner

If you bypass the built in voltage regulator, then you'll probably be getting voltages that spike up and down. It wont be a consistent charge like the regulator provides. I would recommend finding an automotive electrical specialty shop in your area and having one built for you.

TheDurk

Uhhhh....transformers don't work on DC. You'd have to convert to AC and back again. Don't go there.

corax

Have you measured voltage at your amp? If you're dropping voltage on the way to the amplifier, that should be your first stop to getting more power there - reduce the voltage drop and make sure your grounds are top notch. Or just buy a bigger amp if all you're looking for is more volume.

I would advise against tampering with the voltage regulator (the alternator is internally regulated), just think of all the expensive on-board electronics that will protest if something goes wrong and you start spiking them - most OEM electronics are designed to be happy from 11-16 volts.

wyoming9

iTrader: (1)

I am not sure and doubt it would work.

There is not a whole lot to work with on there little alternators but on truck alternators you could adjust the voltage up on the regulator.

A phone call or trip in person with all the information at hand to your local alternator rebuilding shop should answer your questions .

Also the upgrading of the grounds the wire off the alternator B terminal to the power distribution block and the correct size wire to your amp can make a big difference.

nv4runner

The heavier the gauge the better for both power and ground. Grounds should be clean metal to metal contact with as little paint between the terminals and the frame/body as possible.

TheDurk

In theory he's right--on a 3-wire alternator an in-line resistance on the sensing wire would raise the voltage output by the alternator. He wouldn't be 'by-passing' the internal regulator, just fooling it. So spikes would not be the issue, just excess voltage. That said, I have never seen it done and it would make me nervous. But I would bet someone HAS done it.

I'd certainly try the other suggestions for raising charging voltage to spec 13.5-14.5V. Any more would be dangerous to both battery and electronics. Excess charging voltage can cause hydrogen outgassing and thus an explosion. It's the regulator's job to be sure this does not happen. Guys on my tractor board have effed up gen to alt conversions and had this happen. It's not pretty.

4rx

I wouldn't want to risk bypass the built in voltage regulator because there are some sensitive electronics that can be damaged. Unless someone has had done to the 3rd gen 4runner, anyone?

My h/o alt is set at 15.1v but it doesn't do the job. It left me scratching my head. I have a lot of 1/0 gauge wires and the connections are excellent. It doesn't even drop .1volt from front to the back batteries and to the amp while playing music low. It drops about .8v at full tilt because of my amp is pulling about 350amps of current. I really don't have problem with 13.0v daily but just want to raise to 14.0v daily. I'll keep in mind with the light white gauge wire but not right now.

ETRNL

Do what I did, go online find the site that has 5F capacitors for $70 and buy four of them. I have zero problems with voltage fluctuation even running electectric Fan, subs, 130w high beams, A/C, and dc/ac converter for laptop. Granted I do have a built 210w amp that puts out ~150 at idle.

4rx

capacitors are a no-go. It is not for high end car audio performance. It actually can hurt its performance. Go read up for more information about caps on stevemeadedesigns forum. There are several 10k, 20k, even 30k watts that doesn't have capacitors. Some have 2 to 4 alternators and 2 to 10 batteries.

nv4runner

When you're running so many batteries you should have no need for capacitors... since the primary function of a capacitor is to store electricity. Another use includes filtering out AC current, which would interfere with any sound system. There is no reason to believe that a capacitor will hurt performance though. I think you might want to investigate a different site that deals with high end sound systems to find out what they do. Just like you said, you might need 2-4 alternators and 2-10 batteries to get the performance you are looking for.

ETRNL

Hmm I have never heard that for car audio. Key downs on The other hand I have heard of that but never understood why. A guy I know has a suburban with 9 alternator and I believe 9 batteries separate from the vehicle system running 18V I don't know how he has it wired but I do know that he is putting some major power in the air and he said something about no caps. Anyhow I put in my 2 cents so good luck man I am interested in what u come up with.

liquidtouch

You need a Custom built alternator