cjdavis618

Like title says, have a 2010 Silverado Crew Z71. Battery cranks truck fine, but then after running a short while charging the battery, the alternator will drop voltage and not restart charging until truck is restarted again.

Problem is I have lights, etc on the truck that needs some amperage and the truck isn't charging at all until I restart. If the truck was monitoring voltage and realizes that it needs to charge again, that is one thing and would be ok. But this truck has been drained down to 10.5 volts while running and will not charge until I shut it down and start it again.

cjdavis618

Found some interesting info about this online. Sure explains why it does this, but I still don't think it is working right.

Chevrolet Silverado 1500: How does the charging system work - JustAnswer

tech2

the system should not drop to 10.5 volts at anytime. its may allow voltages as low at 12.5 in fuel economy mode but not lower. The truck should be setting messages on the DIC and turning on the charging warning light at voltages that low.

What aftermarket stuff is wired into the truck. If wired in wrong the charging system battery current sensor may not recognize the draw on the battery.

GMcerttech

sounds like your over heating the coils in the alt and the truck starts running off the battery causing it to drain below 12.6 volts. probably need a new alt but if you dont get it working properly soon you will need a new battery.

cjdavis618

I've found DC engineering has a dual alternator kit that will allow me to bypass all of the trucks "Smart" charging features and just add a second high current battery to run my inverter, lights and stereo. May affect mpg a small amount but it gives me a completely separate charging system for the high amperage equipment.

This is the best option for me and the kit can include the second alternator or just the bracket for a second factory alt.

tech2

um, ok...or you could run the aftermarket wiring through the current sensor loop...it may pick the additional draw and run as designed. How many amps are we talking here to run the add ons?

cjdavis618

Current sensor loop? I have a dc clamp meter so I assume that there is a similar system built into the truck. How would that be done to add my equipment through it?

As for Amperage: If I were to turn it all on at once it would be at max 150 amps based on fuses breakers from all of the devices. I estimate 80% total usage if running all at the same time max power. (Which I never do)

Having the battery run low also presented another issue this week. I will post on that in a sec with what I did to fix it.

Thanks