opto_isolator

iTrader: (8)

See this photo:


This is a photo of the fuse box under the hood, near the battery. The red squared in area is what is referred to as the ELD, or Electrical Load Detector, for our car. The ELD is essentially a current transformer that monitors the amount of current draw the car is pulling from the battery. This amount varies from time to time depending on what you have turned on (various electrical devices). The ELD will output .1 - 4.8 volts to the ECU. This reference voltage is what tells the ECU to increase or decrease the field strength in the alternator, which in turn bumps up the output of the alternator.

I have recently performed a test on my charging system, because I was / am having problems with my amps cutting out. I have traced it to the system voltage not being high enough - which is causing the battery to be strained. Essentially my battery is shot.

Back to the subject at hand though. The ELD. Since all aftermarket electrical feeds are pretty much tapped off of the positive terminal of the battery, the current path is not flowing through the ELD. What does this do? All of the amplifiers, LCD monitors, and pretty much anything else that isn't fed through the factory wiring of the car draw a lot of current.
Since the ELD isn't detecting any additional current draw from the battery, it is going to keep the alternator's output at minimum (12.3 volts) - just enough to keep the battery charged, plus enough to run the systems of the car.

Esstentially this poses two problems / issues.

1. You are not getting the most bang for your buck when you run your stereo equipment, since the system voltage is not at 14.4, but usually lower unless other accessories of the car are active.

2. This is going to put a lot of strain on the battery and possibly the charging system.

There is one possible remedy to this that I can think of at the moment (besides turning on something in the car to bump the system voltage up), and that is to hardwire a 0-5 volt signal into the ECU with a rheostat in line, to be able to manually adjust the output of the alternator.

Why not just run the 5 volts directly to the ECU? Honda designed this system the way they did for a couple of reasons. The first is to save gas. When the alternator isn't putting out its maximum power, there is less rotational resistance due to the electrical nature of the magnetic fields - this causes the engine to work less, thus saving gas. The second reason in my opinion, would be to save wear and tear on the alternator. If you were to drive around with the alternator output maxed out 24/7, your alternator isn't going to be around for too long.....

If you decide to try this - I am in no way held responsible for what happens if you damage your car or yourself! Take this post as information only - I may attempt the above modification myself, however I don't plan on doing it anytime soon (due to the fact that I need my car all the time at the moment).

gearbox

iTrader: (95)

Well I sort of knew this already, and really it's stupid of Honda to do. My system almost always sounds bad because voltage is BELOW 12V! Unacceptable, and I'm surprised everything is able to run like this. I know other cars without this problem, so maybe our alternators are extremely weak and can't stay at full power all the time.

When I took my car to the dealer for a system check, they said my amps were drawing straight from the battery. I have an optima yellow now, so it isn't as much of a problem. Still the stereo and amps are mostly running off 12V.

LudlamTheory

better solution for you

buy an aftermarket alternator

doubledeuce2k2

iTrader: (20)

they have to design it this way. if they used a voltage based model, once a battery started to get old, the alternator would run 24/7 to try to get to a voltage it couldn't sustain, killing 2 electrical components. if you are running 1.5-2k+ rms on a bone stock system, i'd expect you to know the potential dangers to the charging system. an audio system for most people is not gonna hurt the system.

that said, i know we have a manual switch already built in for the alternator on lx/ex models, it's called the power window switch .

Jaykuai

iTrader: (2)

but would that be the solution? the ELD still controls the alternator

gearbox

iTrader: (95)

New alternator will also use even more hp than the old one! Oh well.

are6

well, would there be an issue if you were to hook up your added accessories (stereo, etc) AFTER the ELD instead of right at the battery, so that the computer sees the currrent draw from your amps, etc?

gearbox

iTrader: (95)

Well I guess there may be a way. But i your system is bumping all the time, the alternator will just stay at 14v all the time and burn out.

are6

I don't really have too much of a system, just a 200W amp pushin upgraded speakers all around and a 200W(?) 10" powered subwoofer (infiniti basslink)....think this may be too much?

opto_isolator

iTrader: (8)

Yes and no. The ELD is hardwired inline with the main 80 amp battery fuse. If you were to wire your amp AFTER the ELD bad things could happen - such as if you blow your battery fuse - your car would die due to lack of power.

You definitely don't want to do that, as the fuse is a failsafe....you'd be fairly close to the threshold of blowing it if you hooked all of your electrical gear up to it, as its only designed for the load of the car and its accessories.

As far as installing an aftermarket alternator, there are certain connections that must go to the alternator - if you just throw one on that isn't compatible, its going to cause problems.

The window switch solution is only a 3-5 second fix. As soon as you release your window switch the ELD detects a current drop and bumps alternator voltage down to 12.3 unless you have other devices drawing current. I've verified this with a fluke.....

The only real compatible solution is the one which was stated in my original post....

tbaleno

Is there any way to maybe tap off an output on the radio (speaker out or pre out) to a relay with a resistor going to the ELD or something to bring up the voltage.

I'm not good with electronics so I don't know how realistic this is.

opto_isolator

iTrader: (8)

It is possible - however I am not sure at what current the ELD will start to bump up the output....Check out this PDF, it also gives a good explanation of how the ELD works:

http://www.smpcorp.com/download/view/Tt1Q98.PDF

are6

hmmm....if you were REALLY inclined you might be able to get ahold of and 80A automotive breaker from somewhere instead of an actual fuse. That way, if you DID pass 80A, the breaker would trip, but reset itself or you could easily reset it (depending on what kind ya get). But this would include some soldering, etc. I dunno, it might not even work right...just a thought...

tbaleno

Does turning on the headlights either parking lights of full headlights cause the voltage to stay at 14.4?

gearbox

iTrader: (95)

Well turning things on will cause the voltage to go up, but then eventually it will drop back down. Most of the car's accessories can run off the battery, so it's not an issue. Mine has been down below 12v most of the time.

And the funny thing is this voltage drop only occurs in the summertime. I've never had it drop to 12 v in the winter, even when the car is warm.

opto_isolator

iTrader: (8)

Yep, but remember that even though the voltage goes up - the lights (or whatever you have on) are consuming current. I recently purchased the supplemental Helm electrical manual which has a shitload of info about the wiring of our cars. The factory electrical loads such as the cabin fan draw quite a bit of current (upwards of 15 amps!)....

To be quite honest, with an aftermarket system installed - upgrading the alternator to a 150A really isn't a bad idea (as long as its still compatible with the present system - to be so it would most likely need to be a rewind, which I've heard really aren't that reliable, and are quite expensive). I've seen a few on ebay every once in a while, lots of dough though, over $200.

A while ago I was doing a little bit of research regarding alternators from other vehicles. The stock alternator is made from Misubishi or something like that (not sure - another car company)....Other models of their cars MAY have a higher output alternator which is compatible with ours (ie same mounting brackets and wiring). I never really completed looking into it - but it would definitely be cheaper and more reliable than a rewind / refurb...

doubledeuce2k2

iTrader: (20)

what if you wired the RCA output to the ecu with a switch? so you could switch it back to normal. most people running systems that should worry about this have aftermarket HU's with max output levels around 4-5V. when you've got the music loud, high output voltage would kick the alt. on.

i would never mess with this stuff at all. and i consider myself more than proficient in wiring and reading schematics. this is more idea than anything i would suggest actually doing. ****, you might net a few extra watts for what, .5dB, deafening yourself a few weeks earlier? i just like a good discussion.

opto_isolator

iTrader: (8)

Just thought of a better idea tonight. The cigarette lighter socket should trigger the ELD to sense a load....In my case, since I am installing a turbo, I am also installing extra gauges. These gauges are going to be tapped off of the cigarette lighter circuit....so.....this in theory should keep the voltage bumped up most of the time due to the extra current draw.

On a side note, I am going to see about hooking up a current clamp to the alternator wire - I am really curious to see what exactly is coming out of there....

LudlamTheory

rca signals are ac voltage, not dc. it would send the thing ****ing NUTS. lets say 4v headunit out, the ecu would see a crazy variance between -4 and 4v at whatever frequency is being played through the radio

tbaleno

What if you put the rca signals through a bridge rectifier circuit?

LudlamTheory

then you have to remember duty cycle. music is dynamic, heavily dynamic. one would be playing sine waves to actually see 4v for a reasonable amount of time. otherwise it would just be milliseconds of voltage.

yoiu also have to factor in useable voltage. lots of manufacturers rate their ratings at MAX output, not at all taking into consideration distortion, clipping, and other crap. on top of that, even those max ratings are usually underrated

tinman

Interesting.....

Seems to me, that if the computer GROUNDS the C signal to the alternator in order to turn it off, and floats it somewhere in between for charging, then to increase the voltage in general would require the addition of a few ohms of resistance in the C wire. I'll have to look at that. Probably 10ohm or so should bump up the system voltage without throwing a code.

opto_isolator

iTrader: (8)

I belive that's correct....

doubledeuce2k2

iTrader: (20)

yeah it was late, forgot about that. slap a diode on and the thing would go less crazy, but i want to see what it does. i bet you would just end up with the alternator constantly running anyways, just trying to be creative.

about the 10 ohm thing, maybe that does work. but again, there wull be periods of time where you don't need that extra voltage, wasting fuel and alternator life. it doesn't seem to provide an as-needed fix

diskreet

iTrader: (1)

all of this is why i bought the JL 500/1 amp instead of a crossfire VR602 for $100 more. Damn what were they thinking?

*ponders on how over 240 extra watts rms will sound*

jttegx

iTrader: (3)

[QUOTE=opto_isolator]
As far as installing an aftermarket alternator, there are certain connections that must go to the alternator - if you just throw one on that isn't compatible, its going to cause problems.

QUOTE]

how and what kind of problems?

gearbox

iTrader: (95)

High output alternator will draw more power and rob hp from the engine to operate. In addition, you may seriously damage the electrical system if too much current is being produced.

paradoxblue

iTrader: (1)

wow good info. is there a way i can hook up a digital meter in my car to display what im running?

would be a ncie mod to have a lil led screen

sleekcivic2004

iTrader: (4)

Keep us posted on this...when you get a chance to look into it. I am about to be running an audio system in the above 2k range and could definately use the extra power. A little wear and tear on the alternator is the least of my worries at this point...

opto_isolator

iTrader: (8)

Wow - old thread!!