christmaspie

So those who have been around for a while might know of the discussions that have taken place regarding aftermarket alternators, stock voltage regulators, and the almighty Electrical Load Detector. Well, after slight prodding, I banged out some quick tests to see whether or not my audio system (which bypasses the ELD) is taken into account by the stock voltage regulator.

Measurements were all taken at idle. The variables are: (1) my system being either completely off or cranked up to 25 (which is above my highest comfortable listening level) and (2) my air conditioning (A/C) being completely off or turned to max.

When the system was on, a 45s song clip (the beginning of Mr. Writer by Stereophonics) was looped. Voltage min/max and current readings for each step were taken in this 45s period and then repeated after a variable change.

Results were basically inconclusive. I know I need to find a music clip with more energy and I think I'm going to extend testing duration to a minute. Also, next round will involve tests @ 2K RPM (I need more hands!!).

At low currents (A/C off) the alternator appears to react to the demands of the system.

At high currents (A/C on) the alternator does not appear to react to demands of the audio system.

Questions encouraged, I'm sure this isn't very clear as it is.

The current clamp works by converting each amp to 1 mV. So, the accompanying meter display is set to mV, a reading of 4mV means 4A passing thru the current clamps jaws.

Here's a technical breakdown, current vs. maximum and minimum voltages.



Cable A - going from the positive post of the battery to all of my amplifiers and the deck to my system



Cable B - output from the alternator, it runs to the fusebox



Cable C - main power for the vehicle, the only cable running from the battery + post to the vehicle fusebox



Cable D - feed from (or to, whatever) chassis ground to the negative post of the battery. 4mV reading means 4A are coming into the battery. The engine is on and alternator is working.



Cable D - this time with the engine off and the A/C fully cranked on. As you see, the battery is putting out a bit of current. -29mV means 29A of current is flowing out of the battery, running the air conditioning system.



This meter took care of voltage minimums and maximums over each 45 second period during which current readings were taken.



The equipment, Fluke i410 current clamp, Fluke 12, Fluke 111

FoSho

Damn dude....I bet you can do some diagnosis, I wish I could get my techs to go that deep.....you want a job? I need a tech!

christmaspie

I am very happily employed but thank you.

gearbox

iTrader: (95)

seems to me like the eld reacts to a new power-requiring device and then forgets about it a bit later. like if the readout is around 12v, then you turn the heater on, it will shoot up to 14v+ immediately. but then after a while it goes back to 12v even tho the heater is still on. i think its def a weird setup and maybe by running the stereo loud and it taking power away from the other car devices is what makes the eld raise power and not just due to the stereo itself.

Envy

iTrader: (1)

^^^ i like that theory.

my speculation: everything in the eld is prioritized, right? so what if the battery is somehow in that order, and when a stereo drains the battery, the eld sees the drained battery and re-fuels it. but this would also mean that the battery is lower importance than the a/c.

which is illogical. so ilike gearboxs theory

christmaspie

ELD schematic:

christmaspie

and for those that need to get up to speed on the ELD: https://www.civicforums.com/forums/2...-detector.html

gearbox

iTrader: (95)

my brain hurts lol. isnt the whole purpose of the eld to save alternator life by cutting power when its not needed? and it will do this no matter what is hooked where on the car? it cant be that a mod stays "hidden" because it will have some effect on the car which the eld will pick up.

christmaspie

Yes.

Well, that's where the uncertainty lies and why I've done these tests.

But if the current doesn't directly flow thru the ELD, that's kind of the concern.

If you look at the tests I performed with the A/C on, there's no question the current being delivered to the audio system came from the battery. So it bypassed the ELD. And we can see the alternator didn't make any more current at this time than it did with the system completely off.

Yes my brain is starting to hurt a little too.

gearbox

iTrader: (95)

how about this test. after the car is at idle for a while and the eld turns the alt down to 12v, turn ON your radio that was previously off and already set to a high volume. so that way, its a completely new addition to the electrical load and will draw alot of power on startup.

another interesting thing is my new 50w hid kits. i have them wired directly to the battery with relay harness and when i turn them on with the car at idle, you can actually hear the engine bog down considerably. maybe more than the a/c kicking on. it would be interesting to see if the voltage goes up because that is a big amp draw on the charging system but should be "hidden" as you say from the eld.

christmaspie

I like it, I'm sure I can work that into the next round of tests. Thanks.

electric130

iTrader: (44)

great work man. still a lot of questions to be answered. we're on the verge of getting an amp clamp for my department at work. i can use that and check my lighting harness which has a draw of 340w constant (low beams, high beams and HID fogs) directly from the battery. good info

Unevolved

Wow, I'm very impressed. As negative as this sounds, it's rare to see a truly technical discussion on these boards, and as an engineering student, I'm thoroughly interested. Subscribed.

Oh, and an imaginary +1 for you. Wish we could change that setting.