# Anyone running a HO alternator with an internal regulator?



## theonlypheonix (Oct 8, 2015)

Isn't the company you bought the alternator from any help with this? Should be a common problem with any car with the new RVC or like charging technology. You know you will be loosing any advantages of the RVC charging technology by bypassing the original design (around 8 miles per tank of fuel for the diesels)?

Maybe more of a problem then just "tricking" computer. The computer wants to control the voltage under varying engine load conditions/temperatures, etc and if it can't do that because the replacement alternator has it own regulator it may still set fault codes?


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## ChevyGuy (Dec 13, 2014)

That's not going to be easy. The Cruze is designed such that the BCM is the voltage regulator. What's more, the set voltage changes depending on what's going on. Less when engine power is needed, more when you're braking. 

I agree with theonlypheonix that the company should help you deal with this. But I'm pessimistic about internal regulation working. Not without reprogramming the BCM with a custom program so it doesn't worry about the alternator.


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## brian v (Dec 25, 2011)

I think that you could possibly try to put a resistor on a lead to the battery reducing amperage thereby tricking the BCM into a charge signal.


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## bsumpter (Dec 18, 2013)

Hey guys thanks for the replies. The company did offer 2 different versions, I opted for the bypass. They did offer to put the stock regulator back in if I can't get it to work properly. I was also thinking along the lines of adding a resistor to the alternator connector but didn't know where to start ohms wise. Also wonder if BNR could tune it out? Not sure on that one.


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## theonlypheonix (Oct 8, 2015)

Putting in the correct value resistor on the appropriate lead should get the system to see the alternator output voltage but I think you will still have problems because under operating conditions with the original alt/reg the system is very active in adjusting the voltage and doing checks. If the system does not see what it wants when commanded, I assume it will still set a fault. There is another posting here that gives a summary of all the things the RVC system actively does while it is in normal operation. I think you should review that so you can see the obstacles you're up against. If someone could tune out the faults that may be your easiest route. But then again you lost the advantage of the RVC system fuel saving of 8 miles per tank.:sad010:


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## ChevyGuy (Dec 13, 2014)

I didn't find the post mentioned, but I did find this: Chevy Cruze regulates voltage to boost fuel economy - Autoblog

Realistically, I think you have two options: Make the new alternator respond to the BMC's commands, or find someone who can "tune" that function out of the system.


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## Toma (Nov 8, 2021)

ChevyGuy said:


> I didn't find the post mentioned, but I did find this: Chevy Cruze regulates voltage to boost fuel economy - Autoblog
> 
> Realistically, I think you have two options: Make the new alternator respond to the BMC's commands, or find someone who can "tune" that function out of the system.



I'm about to buy a HO alt for my 2012 chevy cruze eco. I believe this company has a selection so that I can avoid running into the same issues that OP here is having.

"EXTERNAL REGULATION (MANUAL 13V-20V):
○None 
○+$130.00 EXTERNAL REGULATION-MANUAL 13V-20)
"

Should I select none?
Or do I need to pay the extra 130$ to avoid the same problems as OP


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## Blazekm805 (9 mo ago)

bsumpter said:


> Got my HO alternator on, runs great, awesome voltage. Only prob is that it has it's own regulator and the car doesn't like that. Thus meaning the alternator isn't plugged into the car, making it think there is no voltage. This puts the car in low battery mode or limp mode. I know it runs off pulse switch modulation. Just wondering what I need to do trick the computer to know that it's charging. Any help is appreciated, Thanks!
> 
> Brandon


Did you ever find a HO alt that worked for the 2012 cruze? I just bought a 390amp one from BrandX but it isnt charging my stereo correctly...


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