Charging system issues... I think

01’ 2500/24v/ nv4500 swapped/ 4x4 / edge tune
Both batteries are 2 years old and test hood. SERP belt is tight. Truck starts no problem at all BUT ... immediately after starting it starts charging, then stops for 30 seconds, then charges for 30seconds , then starts charging again and continues charging for the duration of the drive. Weather it’s 10 min or 3 hours. If you shut it off the The whole sequence starts over again. Hot or cold. Is this normal? It seems way to consistent to be a bad alternator. I been driving it this way for who knows how long because I only started paying attention to it when the weather got cold and now I’m sitting in it in the morning while it warms up. Any thoughts?

For the record it’s on , off, on, off , on till you shut it off.

Sounds like you’re seeing your heater grids cycling on and off. They continue to cycle until you get the truck over 15 or 20 MPH. They draw a LOT of amps and really makes your volt meter swing.

^^^Whs

I've seen it exacerbated when the grid heater solenoid starts to fail...virtually becomes an uncontrolled power sink.

Yes disconnect the grid heaters and see what happens

Well that makes sense, thanks guys. I didn’t know the grid heater ran after startup. I guess for once this truck is doing what it’s supposed too, hahaha

itll make the lights dim.the alt guage will drop...sometimes ya can even hear it draggin the engine down

Quick follow up, I disconnected the grid heater and it charges normally. All good, I was worried about nothing. Thanks again guys