HO Alt with or without external regulator.. Need some advice

[sbarber82 10+ year member]

Hello all, I have a NBS chevy silverado with a 5.3l motor. The NBS trucks have a regulator that cuts the voltage down from 14.4 to 12.5 or so to help save gas. I am going to install my 300a HO alt this weekend and I am not sure if I should use the external regulator I bought with the alt or not.

Seems pointless to have the HO alt if my PCM is just going to cut its output to save gas when I am trying to keep a steady 14.4 voltage to run my setup.

Does anyone have any experience with this technology from GM that cuts the alts output to help save gas?

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[Dj-torn 10+ year member]

Dont have the experience with the system, but if this is true, you want a higher voltage to keep things running cool. With this said if you don't use the regulator, you need something in place (battery or cap) to absorb the spikes & dips in the power output of the alternator so you do not exceed the power rating of the equipment.

 

[sbarber82 10+ year member]

well it doesn't spike it just dips for long periods. It starts at 14.4+ then sometimes drops to 12.5 or so

 

[truckramrod 10+ year member]

Rvc has a sensor around the Neg cable. If you are cranking on the system it will see that and boost the voltage. You will see better performance with the ext. regulator but it may set a service light.

 

[sbarber82 10+ year member]

Rvc has a sensor around the Neg cable. If you are cranking on the system it will see that and boost the voltage. You will see better performance with the ext. regulator but it may set a service light.

Thanks man. I am going to run the alt without the ext reg first and see what the numbers are. If I am dropping to much I will throw in the ext reg

 

[truckramrod 10+ year member]

You can test performance of it with the tow/ haul mode engaged or the headlamp switch on. That can allow the system to boost voltage. I have customers occasionally ask why their systems aren't charging.

 

[Joe562MMA 10+ year member]

mechman has a external regulator that lets you set your charging rate so u can set it too 14.5-15.8 i believe check out their website see if they have one for your application

 

[sbarber82 10+ year member]

GEtting a external reg is not the issue, that is easy. Just wondering if i will need it

 

[gckless 5,000+ posts]

If this was my vehicle, I would get an external no doubt.