alternator duty bypass

kickass audio · August 30, 2019

Does anyone happen to know if there is a way to bypass the duty signal of the alternator and not set off an error for the alternator? I would love to upgrade my alternator to a high output alt with an external regulator but I know that would set off the alternator charging error as a result.

flyingfool · August 31, 2019

might need to send the body computer in to one of the companies for reprogramming and disabling error code signals.

are you having issues with not enough charge output due to aux electronics like lights? if you are try pressing tow haul button. this increases the power output to the battery from the alternator by telling the computer you have to feed power to a trailer should bump it up to 14volts.. let me know what you discover

kickass audio · September 1, 2019

It runs fine but a buddy has an alternator I wanted to buy that has an external regulator and I know if I unplug the alt it will throw a code since it can't control the voltage any longer. I wonder how the output is of aftermarket high output alts when the duty signal commands a lower voltage.

flyingfool · September 1, 2019

sounds like you have some homework to do bud..

Darksky · September 1, 2019

The increase in voltage output with the tow/haul button is new to the uninitiated (me). Thanks for that.

So, for long running times on a parked vehicle with external lights (such as a Chief’s truck). That is not equipped with the dual battery option, would punching the tow/haul button before exiting the vehicle be a good idea for the longevity of the vehicle’s electrical system?

RACERX7775 · September 2, 2019

I added a second battery because of my stereo system. Sometimes pull over 100 amps easily. And have no issues.. leave it alone. Itll be ok.

davester · September 2, 2019

Probably

9 hours ago, Darksky said:

The increase in voltage output with the tow/haul button is new to the uninitiated (me). Thanks for that.

So, for long running times on a parked vehicle with external lights (such as a Chief’s truck). That is not equipped with the dual battery option, would punching the tow/haul button before exiting the vehicle be a good idea for the longevity of the vehicle’s electrical system?

Probably not if there is nothing drawing a significant amount of power. If something is drawing power, then it probably would be more useful to figure out a way to give the truck a high-idle, as alternators don't produce as much power at low speed.

Pearl2017 · September 2, 2019

If what you're after is additional amperage then additional voltage in tow/haul probably will not do you any good. The added voltage is there to keep the lights from dimming when the added harness length and lights/accessories of a trailer is present. These smartly controlled alternators output current to meet demand dynamically. If your continuous total current demand is higher than the max alternator output you should look for the HD version alternator like they put in tow trucks or maybe X500HD. Additional battery is a good idea if you just need to cover transient amperage demands.

Edited September 2, 2019 by Pearl2017

Darksky · September 2, 2019

I get it. However, I don’t own the City’s trucks. It was just an idea of a literal button push to be useful. Those trucks were part of a bulk purchase. They weren’t specced out for duty.

flyingfool · September 2, 2019

It takes about 2 minutes after hitting tow haul button on my truck to peak charge the batteries up to 14 volts, but i have no aux lights or stereos.. if it takes longer to re-charge than you might want to let it sit running in tow haul for about 10 minutes then switch it off

kickass audio · September 4, 2019

What I am thinking about doing now is rebuilding the alternator. I have an old t-case style alternator from my GMC Envoy and it works perfect. I didn't get to measure the current one in my truck but everywhere I looked online said that the gm large case alternator in our truck is the same size as the alternator I had in my Envoy, the only difference is the mounting ears on the case. If they are truly the same I figured I would try and take apart the alternator and swap the cases around and make it fit again. I don't know if the regulator can be swapped for a higher output alternator though. I'm pretty sure the only part that matters is the diodes and rotor/stator for the alternator but I could be wrong. If I need to I could always try to cut a harness for the alternator to go from the 2 pin on the truck to my old 4 pin on the alternator and make it work.

RACERX7775 · September 4, 2019

I hat to ask, but are you having issues? What are you needing out of this system that you cant get out of it now? Im not sure, but doesnt the BCM control the output. It does have a sensor on the ground cable to see return voltage. If your alternator is fine for your setup, why buy an alternator from your buddy... I am just thinking reality here. Is it just to say you have a big alternator? Did you put a meter on the truck to see how many amps you are pulling? I think the lstock alt is like 140 amp. What do you have in the truck now that needs the new alt?

RACERX7775 · September 4, 2019

Here is my setup in my Excursion. Its got a DC POWER 500 amp alt. and 5 batteries. But I pull well over 300 amps from it.

kickass audio · September 4, 2019

1 hour ago, RACERX7775 said:

I hat to ask, but are you having issues? What are you needing out of this system that you cant get out of it now? Im not sure, but doesnt the BCM control the output. It does have a sensor on the ground cable to see return voltage. If your alternator is fine for your setup, why buy an alternator from your buddy... I am just thinking reality here. Is it just to say you have a big alternator? Did you put a meter on the truck to see how many amps you are pulling? I think the lstock alt is like 140 amp. What do you have in the truck now that needs the new alt?

Since I don't want to buy yet another amp that I cannot sell I am going to run my old DC audio 5.0k amp at 4 ohms. The voltage from what my oscilloscope was showing was dropping to like 13.9 when it was trying to keep it up to 14v. My big concern is how hot the stock alternator gets and I don't even have the amp connected yet. I figured an upgraded one might help give me more headroom. That sensor on the ground cable I was thinking is to sense how many amps of current are being passed through. I shoved a 4ga cable through that hall effect sensor to send the power to the second battery under the hood. I would really love to run 1/0 power and ground to the second battery but there isn't enough room to squeeze that in the sensor with the factory ground wire.

Edit: The one thing I noticed out of my truck is when I had wired the precision power pc2350 amp up to the sub to a 2 ohm load it would make the cluster backlighting dim and brighten back up multiple times during huge power draws and the headlights would show some flickering but nothing that intense. Those are the only two things I noticed during large power draws, nothing else was affected by it.

Edited September 4, 2019 by kickass audio

RACERX7775 · September 4, 2019

Dont bother with the running the wire through the sensor. It still works perfect. I run a power wire from stock to second battery. Another from alt to second battery. Ground wire from second batt to engine. Another from second batt to chassis. Then power and ground from second batt to stereo system. Of course I used a few breakers to completely isolate everything quickly if necessary. All cables are 2/ welding cable except the little jumper on the top of the stock battery.

Edited September 4, 2019 by RACERX7775