Oppie,
I have some experience in design of emergency warning systems for emergency response vehicles, and I thought I would pass on some of the things I have picked up over the years. First, in no way, ever, should warning equipment be attached to the factory wiring harness of the vehicle being modified.
Specifically, vehicles that fall under the umbrella of NFPA oversight shall have a warning system that is “Stand alone” except for the connection to the charging system. Because you are a volunteer firefighter and the vehicle is private, than obviously this does not apply. Most states have very specific laws about the amount of light discharged as to achieve the adequate amount of light at the right distance. It absolutely is not a case of adding strobe packs and LED’s until it “looks cool”.
Keep this in mind Oppie, because the vehicle is private, any modifications you make to the vehicle that are used in warning other drivers that you are operating in an “official capacity” (of any kind) and requesting the right of way, is your responsibility alone. Should an accident occur while you are responding to an emergency, and fault is determined to be yours, then the liability will be yours alone, not the agency you work for, or even your personal insurance. To my knowledge, no insurance company will insure for use a private vehicle that is operated in an “emergency response capacity”.
That being said, my advice to you would be to restore the factory harness to OEM specs, install the appropriate heavy gauge supply wire to an isolation solenoid, and pursue the Optima deep cell you spoke of.
I admire your service as a volunteer firefighter; often this is the only fire service a community has. I myself was a volunteer for seven years before attaining a job at a full time agency, but please be careful, your service will be in vain if someone is injured because of well intentioned over zealousness.
Best of luck,
Tom
:santa: