What is going on with my electrical?

[eltigre2213]

Hey guys! I’ve been struggling trying to figure out what’s been going on with my voltage and I guess my knowledge may not be to great but I need help to see if it’s my equipment or if I’m doing something wrong! To start I have a Mechman 240A, 205A at idle (red card); XS power 6500 AGM starting bat, GP Audio fuses and true OFC 1/0 awg big three and run back to trunk; limitless lithium 500A relay; D4S  JP40 40ah Lifepo4 Lithium battery (lithium is isolated as of now from agm, being fed directly from alt). Salt 2k running a 12” Xv3 @ 1ohm and skar  rp-150.4ab @ 4ohms.

 

I have a voltage drop of .05V between alt and lithium in trunk. My car is a ford pwm controlling alt and charges at 14.4V cold and drops to 14.1V hot. At full tilt my voltage drops to high 12s and low 13s, Both at alt and lithium, and almost immediately jumps back up to 14.2 The most I’ve clamped my salt and skar pulling together (at clipping) is 210A @ low 13Vs and my alt feeding 155A. My goal is to stay in the 14Vs, is it the lithium or what’s going on? I would really appreciate the input and/or tips and tricks!

[crispy_chick3n]

if your readings are at idle, that could be the issue. for larger draw your alt needs to be spinning faster to keep up. I wouldn't worry too much about the .05 drop from front to back as that is acceptable for the length of wire that would be there.

 

judging from your equipment, your alt is a smidgen undersize if your audio is pulling 210 amps. your car is going to use more than 30 amps while running. generally, you want to leave 100 ish amps for the car to use while running (depending on the vehicle). you can get a good idea of what the car will use by seeing what the factory size alt is.

 

by the equipment you have listed, you will almost always have voltage drop while using your stereo. you can combat this by adding more battery reserve, but eventually the draw will catch up and youll have to turn it down to let the batts recharge.

 

TLDR, you need a larger alt to keep up with the car and stereo