Honda Element battery circuit PUBLIC

This is an attempt to understand why the battery voltage in my Honda Element drops as much as it does when operating my Ham radio equipment

To get power to my Ham radio equipment, I run two AWG wires that are about 15 feet long to a Power Distribution Assembly in the back of the vehicle and then to the equipment. This model only includes the voltage drops to the power distribution assembly and does not include the additional drops to each load.

The battery model is for a 12 volt gel cell with an internal resistance of 50 milliohms. My measurements on the Optima battery that I use indicate the internal resistance is about 25 milliohms. Unfortunately the tool does not allow me to edit the internal resistance of the battery so the results are somewhat pessimistic.

My amateur radio equipment takes about 10 amperes when receiving and about 30 amperes when transmitting. The 400 milli-ohm load is representative to the transmit condition.