Background: Weak battery at start-up. It had sat on several occasions and only had about 1/3 of its cca capacity, so I got a new battery.
Next I wanted to add some more electronics gear, i.e., subs, amp, power inverter, carputer... so I got a high output alternator.
I installed both without a hitch. Upgraded the alternator to battery wire, and the ground with 2ga. wire.
All is well for about a month.
Now I go on a road trip and decide to hardwire my inverter for my laptop. I pull the positive from the post near the fusebox under the hood, and ground it on the passenger side frame rail.
Problem: After the long drive, the battery light starts coming on, but would go off once I stepped on the accelerator and increased the RPMs. Now, however, the light goes on and off under no pattern that I can see.
I removed the hardwired inverter and the light still comes on and off at random.
Question: Could what I have just descibed cause such a thing, or would it be related to some other problem?
2002 4.0 Liter Engine 4x4
Ford 8.8 4.10 Limited Slip Rear Differential