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Originally Posted by low_bass_makker By changing the rotor excitation voltage. Actually the voltage is controlled not the current. If the voltage is reduced to 12.8 from 14.4 then there will be no current. |
Exactly
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Originally Posted by montyguru this may not work as current is not going direct from alternator to battery. the ELD has a shunt mechanism with resistors. it measures batt voltage, volt reqd and automatically reduces the alternator load. |
The question then is why, when the load increases, does the power dip and amps go off. If your hypothesis was true when the load increased the ELD would have allowed the alternator to charge the battery faster.
I suspect the ELD limits the current the alternator provides to the battery hence when the load inceases the battery is discharging faster than it is charging and at some point it's voltage drops below a threshold required for the amps. The amps then go off and a second later when the battery has regained charge the amps work again only to discharge the battery again and the cycle repeats which is why GTO's car faces the dipping about 20 times per trip.
The ELD was installed to protect the alternator. If your alternator cannot produce the required current to power everything in your car, including your stereo system, it will at some point begin to draw too much current, and the coils withing it will overheat causing the enamel to melt, and the alternator to fail. By limiting current draw the ELD ensures the alternator is not damaged if too make accessories are isntalled.
If the alternator was able to charge the battery at a rate that was faster than the rate at which the amps are discharging the battery there would be no issue.
This can happen only if the alternator puts out more current during idling (than it is doing now).
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Originally Posted by Mpower Assuming your alternator and battery are sound, you're not getting enough juice due to the heavy electrical load. There is a product called overdrive pulley which spins the alternator faster during b2b crawl. Check this out, NST 21922 NST - The Leader In 8th Gen Civic Pulleys |
MPower, would the overdrive pulley work if in fact the feedback loop from battery to alternator via the ELD is controlling the charging rate of the battery?
My understanding of the problem is
The battery is discharging at a rate that is faster than the max charging rate of the alternator-ELD combination. I also believe that since the car worked after being left idle for 3 days and also worked for the first few months that this difference in charging/discharging rates is marginal.
Hence there are 3 options.
a. we mess with the ELD and change the resistor values to increase charging rate marginally.
b. We replace amps/speakers to produce more Acoustic Watts for every Electrical Watt consumed
c. We install a rectifier-regulator circuit at the alternator end (
Charging System Basics) and tap the voltage from the alternator directly OR install a second battery AND dual battery isolator (so one battery does not attempt the charge the other).
Of the 3 options I believe option
a might reduce the reliability of the car (GTO already has one play car), option
c is expensive and complicated altheough in the days pre Class D amplification I have installed dual battery isoaltors for 1-2KW installs and before these myths were busted (
http://www.caraudiobook.com/car_audi...udio_myths.htm). Option b (which was propposed by B&T and others) seems the most sensible option.
To test this hypothesis all GTO needs to do is disconnect one amp (I would recommend the rear channel amp) and live with the "correct" soundstage for live music (front only - no rear fill) for a few days. It does not cost a penny.
GTo please understand this..
a. 12V x 50amps = 600W, if you had a 70A alternator it would be 12x70=840W. If your stereo is drawing an average power of say 500W (assuming 50% of the max total of 1000W rms) it leave precious little for the rest of the accessories (air-con, lights, etc..). Upgrading to a 150A alternator or installing 2 70A alternators would have worked if not the for ELD which will limit the current from any alternator not knowing that the alternator is now a superior one than the one it was programmed for.
b. All batteries have a max charging current. Upgradig the alternator without taking this into account can limit the life of the battery. Hence what we used to do in the old days is upgrade the alternator AND install a dual battery and control/isolation circuit to limit charging current to safe limits of the battery. I hoped that Class D amplifcation would eliminate all this.
c. Adding a capacitor might not help (as Gurus like B&T and Sam Kapasi have testified) but it costs nothing (if B&T has a loner cap available - I have a 0.5F cap if you need it installed in my FIL's car) and is a 10 minute install/uninstall. And by chance if it does help ....LOL.....hey what works, works na?