If your electrical system is inadequate, the ONLY way to fix this, and again I repeat, the ONLY WAY to fix this, is to replace the alternator if your voltage rails are sagging to below 12 volts while the car is running. This is the SOLE source of electrical current for your car when the motor is running. The car's battery is in parallel with the alternator, and while the battery will help to stablize voltage at 12VDC, the alternator puts out a higher voltage, and if your voltage rails are dropping to 12 volts, you're already overdrawing the alternator's capacities, and if your voltage rails sag to below 12 volts then you're also going beyond the abilities of the battery or batteries to stablize your voltages. Both of these symptoms will result in battery and alternator damage.
Well, im going to test it out, but im 99% sure my 110 amp alt is not going to be able to run my re12.1 and jl 300/2. ive already gotten a quote from excessive amperage for a new 210 amp alt. is putting in a new alt something i could do myself, or where could i get it done for me, and how much?