Voltage Regulator Fail

[clickclickw00t]

So I've been pulling way too much power out of my system since I installed it about 8 months ago. AQ2200, HDC312, Alpine type Rs with a MRPF240 bridged, and a stock factory amp for the fronts. I noticed that when I turn my car on in the morning my voltage meter is at 14V even. After driving for 10 min my voltage is at 13.3 (no music playing, AC off). When I turn AC on and some music I'm down to 13.1 At full tilt I NEVER drop below 12.7. Took it to autozone and they tested it - they say my voltage regulator on my alt failed. I know there are threads on here about them not properly testing alternators.

My car is a 2012 Scion TC. I was wondering if it is the computer controlling the voltage? I really don't understand why its falling so low. 13.1 with A/C on and barely any music playing (like 10/40 volume) is WAYY too low for a 2 year old car. Any suggestions?

I'm in NOLA and it gets wicked hot here, and my alt is so close to my headers that it gets hot either way. I could have killed it with the amp, or it could have just died its own death. Again, the alt passes test, but the voltage regulator does not. Battery is fine and rests at 12.7 but I will be replacing it soon with an XS or Deka. Big 3 is done.

[SnowDrifter]

Some cars have a fuel savings mode where they reduce the alt charge voltage.

[clickclickw00t]

Some cars have a fuel savings mode where they reduce the alt charge voltage.

Thanks for the reply! Yea I know some cars have that. How do I find out if mine is one of them?

[Guest DC Power Kyle]

So I've been pulling way too much power out of my system since I installed it about 8 months ago. AQ2200, HDC312, Alpine type Rs with a MRPF240 bridged, and a stock factory amp for the fronts. I noticed that when I turn my car on in the morning my voltage meter is at 14V even. After driving for 10 min my voltage is at 13.3 (no music playing, AC off). When I turn AC on and some music I'm down to 13.1 At full tilt I NEVER drop below 12.7. Took it to autozone and they tested it - they say my voltage regulator on my alt failed. I know there are threads on here about them not properly testing alternators.

My car is a 2012 Scion TC. I was wondering if it is the computer controlling the voltage? I really don't understand why its falling so low. 13.1 with A/C on and barely any music playing (like 10/40 volume) is WAYY too low for a 2 year old car. Any suggestions?

I'm in NOLA and it gets wicked hot here, and my alt is so close to my headers that it gets hot either way. I could have killed it with the amp, or it could have just died its own death. Again, the alt passes test, but the voltage regulator does not. Battery is fine and rests at 12.7 but I will be replacing it soon with an XS or Deka. Big 3 is done.

Completely normal. Toyota's don't control the output but have very sensitive regulators when it comes to voltage drop with heat.. You can expect the alternator to do full output at 13.0-13.2 volts from the factory. On my 270XP I can be in traffic and I will be charging at 13.2 with just my A/C on. Toyota does this because it's really easy on your front battery and wont gas the battery when it's hot under the hood of the vehicle. I wouldn't worry about it.

To go into more detail, when I refer to Toyota, I'm referring to the specifications they gave to DENSO to create the internal voltage regulator for all the vehicle alternators. When those alternators fail, they simply turn on the battery light and will not charge. I have seen it happen first hand many times. If you don't have a charge light, you're fine.

[clickclickw00t]

So I've been pulling way too much power out of my system since I installed it about 8 months ago. AQ2200, HDC312, Alpine type Rs with a MRPF240 bridged, and a stock factory amp for the fronts. I noticed that when I turn my car on in the morning my voltage meter is at 14V even. After driving for 10 min my voltage is at 13.3 (no music playing, AC off). When I turn AC on and some music I'm down to 13.1 At full tilt I NEVER drop below 12.7. Took it to autozone and they tested it - they say my voltage regulator on my alt failed. I know there are threads on here about them not properly testing alternators.

My car is a 2012 Scion TC. I was wondering if it is the computer controlling the voltage? I really don't understand why its falling so low. 13.1 with A/C on and barely any music playing (like 10/40 volume) is WAYY too low for a 2 year old car. Any suggestions?

I'm in NOLA and it gets wicked hot here, and my alt is so close to my headers that it gets hot either way. I could have killed it with the amp, or it could have just died its own death. Again, the alt passes test, but the voltage regulator does not. Battery is fine and rests at 12.7 but I will be replacing it soon with an XS or Deka. Big 3 is done.

Completely normal. Toyota's don't control the output but have very sensitive regulators when it comes to voltage drop with heat.. You can expect the alternator to do full output at 13.0-13.2 volts from the factory. On my 270XP I can be in traffic and I will be charging at 13.2 with just my A/C on. Toyota does this because it's really easy on your front battery and wont gas the battery when it's hot under the hood of the vehicle. I wouldn't worry about it.

To go into more detail, when I refer to Toyota, I'm referring to the specifications they gave to DENSO to create the internal voltage regulator for all the vehicle alternators. When those alternators fail, they simply turn on the battery light and will not charge. I have seen it happen first hand many times. If you don't have a charge light, you're fine.

Can I first say thank you SO much for this reply- this is exactly what I was looking to hear (not really, but at least it saves me time and money to get a new alt).

So you're saying that my alt will not charge at more than 13.2 ever? That's beyond crap. There is a shop by me that rebuilds alternators, could he possibly allow me not only to output more amps, but to charge at a higher voltage? From what I know, it is a stock 120amp alternator. Furthermore, is there a reason that autozone's test determined my alternator was faulty?

Finally: I checked out DC Power and was wondering how much it would be to get an H/O built for my car? And is there a chance that a higher output voltage/amperage of the alternator than stock could affect my stock electrical? Overall I'm pretty satisfied with my system, so in lieu of spending $200 on a new battery, I'd rather save up and spend $4-500 on a h/o alternator and bypass the battery weight altogether.

[clickclickw00t]

Just spoke to the shop. He said it would be about $300 to rebuild it to do 200amps, but he's never worked on a 2012 car alternator, so honestly for that money and his lack of experience I'd rather not even bother. That option is out of the question. My only next option is either a H/O from you or singer, or a battery or two in my trunk.

[Guest DC Power Kyle]

I honestly wouldn't touch it. I've ran 13kw at this voltage and haven't seen a problem. I wouldn't worry about voltage until you want to compete for numbers. As long as you're in the high 12s you're fine for that much power. If you take it anywhere to get it changed many shops will take the OEM components that are expensive and replace it with Chinese to make more money. Just my two cents.