So I have this weird issue with my electrical system. The battery doesn't die overnight anymore, which I had an issue with before. Now when I start the car when its cold my volt meter reads a solid 13.8v, which is great, then once its warmed up my voltage will jump from somewhere between 12-13.3v at idle and sometimes 12.5-13.3v when driving (The figures are the ranges not exactly where it jumps from but are the overall extremes). Every once in awhile it will go back to 13.8v and stay there, but never for long. This is when Im driving during the day with no excessive electrical loads like headlights and radio. When driving with the headlights on the voltage will range from 11.9-12.5v.

Is there a way to fix this? Could it be that there isn't enough good grounds? I really want to fix this issue so that I no longer have to worry about any issues while driving, especially at night, and I also want to install a radio. Please help. Thanks in advance.

 

I hax that issue before which i cured by upgrading to fc fuse block. Upgraded to a 4 gauge cable from alternator b terminal to fuse block. Then i connected the stock b terminal wire to the other side of the fuse blocks main feed (80amps). Lastly, added another ground wire from engine to frame. These upgrades were done after i switched to fc alternator.

 

Yeah I have an S5 alternator installed also, thinking the amount of amps recharged would be a lot better than stock. I do think I have either a 4-6g. wire from terminal b to the fuse box, box to the battery, and only 1 battery to body ground. Are you saying that you have 2 body grounds?

 

Yes, i have 2 grounds on the SA and FB and 3 on the RX-3s as ive relocated the battery in the trunk

 

I think that might be my problem then. If I recall correctly, I only have one body ground. I'll have to go to the parts store and pick up another wire. Thanks for the help, I'll see if it fixes the problem afterwards.
If this fixes it it will definitely be nice to get some tunes while driving, but not complaining about the harmonic symphony I get from the motor.

 

Oh and another question, where did you put the other ground? The ground I have is on the block.

 

Block to one of the driver side idler arm bolts as i hate drilling holes