Is it Possible to get 14.7V from this Charging System?
11-15-2017, 01:53 PM
#1
Is it Possible to get 14.7V from this Charging System? I know there are a lot of alternator threads but I'll throw one more out there.
I have a DR44G, 1-pin connector with a 470-Ohm resistor and a Duralast battery. I used to see 13.8V on startup and 12.9-13.0 on the track under full load. At that point load includes parking lights, 2 AEM 380s and whatever the MS is using for the coils and injectors. I have no dash/gauges, just a tablet and the fan is turned off at 70% TPS. The Batt pos and neg cables are 1/0 running to junctions in the driver's-side wheel well where the pos junction connects to the starter and alternator with 4g cables and a 10g to the fan relay. The neg cable has a junction on the frame by the rear-end on the way to the front, then connects to the block with a 4g, a 8g going inside the car to a distribution block for stuff inside the car and 10g for the fan.
This setup originally had the alternator 4g to the pos junction going through the Ford relay in the wheel well. I recently redid that bypassing the relay with a 2g and upped the neg cable to the block to a 1/0 and also ran grounds from the alt case to the block. Now I get 14.1V at idle and with the hi-beams, fan, aux tranny cooler pump and Viair compressor on, it only dropped to 14.0V. However, with a quick blast at 13psi, it dropped to 13.5V. I'll find out tonight if it drops lower with even more load.
So, I've essentially done the Big 3 upgrade (4 actually) and research shows that a .5V drop under full load is normal, but I am wondering why I cannot get ~14.7V at idle. Is there anything else I can do?
I have a DR44G, 1-pin connector with a 470-Ohm resistor and a Duralast battery. I used to see 13.8V on startup and 12.9-13.0 on the track under full load. At that point load includes parking lights, 2 AEM 380s and whatever the MS is using for the coils and injectors. I have no dash/gauges, just a tablet and the fan is turned off at 70% TPS. The Batt pos and neg cables are 1/0 running to junctions in the driver's-side wheel well where the pos junction connects to the starter and alternator with 4g cables and a 10g to the fan relay. The neg cable has a junction on the frame by the rear-end on the way to the front, then connects to the block with a 4g, a 8g going inside the car to a distribution block for stuff inside the car and 10g for the fan.
This setup originally had the alternator 4g to the pos junction going through the Ford relay in the wheel well. I recently redid that bypassing the relay with a 2g and upped the neg cable to the block to a 1/0 and also ran grounds from the alt case to the block. Now I get 14.1V at idle and with the hi-beams, fan, aux tranny cooler pump and Viair compressor on, it only dropped to 14.0V. However, with a quick blast at 13psi, it dropped to 13.5V. I'll find out tonight if it drops lower with even more load.
So, I've essentially done the Big 3 upgrade (4 actually) and research shows that a .5V drop under full load is normal, but I am wondering why I cannot get ~14.7V at idle. Is there anything else I can do?
11-15-2017, 06:33 PM
#2
Why do you want 14.7 volts? GM is all setup to do 14.1 volts at idle. Most high end alternators like the ones at the audio shops have good enough diodes that they can handle higher voltages, so you can order a regulator and turn those into 16 volt alternator. Usually without an issue. PowerMaster makes some alternators (even in a CS130 case used on LS) that you can change the voltage to match your needs.