I have somewhat of a complictaed question stemming from a simple issue. I have a ton of accesories wire to my car but as of now i have done them all on cigarette lighters. I have 6. I tried to wire directly to an availiable fuse in the fuse box located underneathe the steering wheel. I can not get a power reading from there. I checked my cig lighters and it read between 12 and 13 volts but the open fuse slots on box read 0.

I am interested in looking into an auxillary battery power system for my next truck. I want to have a second isolated battery solely for my accesories. I am a member of the fire department so I would need power for looots of offroa lights, multiple chargers, etc. I wanted to do the whole second alternator thing and have a distributor box comming off of the second battery. I plan on running something like 12 100W lights, some signal lights, and other stuff. Maybe a winch.

What are your opinions and or incite on this topic?

 

I can tell you right away there is more to this than meets the eye to have a reliable and proper system.
First, you should really settle on what you need and no extras just to have them for show.
12 100 watt lights takes about 7 amps each x 12 = 84 amps total at 14.6 volts.
Just the lights alone takes 1200 watts of power at 14.6 volts.
You would need to run the motor at high idle to even keep a second battery from going flat under that kind of drain.
Then you still need an alternator sized at about 100% larger than the drain because alternators are not normally designed to run full output continiously without overheating. Only high/long enough to recharge a starting battery and normal drains associated with the starting motor, stock lighing and electrical loads.
Then you want even more equipment in addition to make the load even higher.
Your bast bet is to seek the services of a shop that outfits and services anbulances and emergency vehichles for their heavey needs.
Advice is to not get carried away with all this and install only what you really need.
The rest could be done off a gas generator in the bed. Much easier and cheaper.
It will cost a bunch of money and bring on problems using an all 12 volt system. The alternator would be a 1/4 as big as the motor plus the weight of batteries erc.
I'm not trying to talk you out of doing anything but get a real perspective on it.
Good luck.

 

I agree it does get a little complicated. One I don't care about having it run while the truck is off. As long as the alternators (charging system) can keep up with it at idol thats fine by me. Also I can tell you that even with the ambulances they will not run while off. We leave them idling all the time so upkeep the accessories. Maybe 12 lights is a little much and I could cut down but at the same time I would much prefer to avoid a generator. That just seems like a pain to deal with.

 

what he was saying is you cant have all these accessories running at idle. thats wayyy to much stuff.

 

i would use a 200 amp alternator (one) off an ambulance and put a second battery in with the main battery. When your using the lights or winch you talking about an hour or two. THey big alternator pushing into a second battery will about keep up with that. If you pull extra out of the battery for an hour it will not hurt. The alternator will bring the battery back up quickly after the acces are shut down. The battery is used something like a big capacitor to store the power for quick use when needed. If you drag it down, it will come back after lights are off.

 

97-02 Ford F150 4.2 High Output Alternator 210 AMP: eBay Motors (item 220475183156 end time May-30-10 12:18:32 PDT)

 

bigger motor--- try this one

2004-2006 Ford F150 V8 270 amp high output alternator : eBay Motors (item 320493086661 end time Jun-24-10 09:37:16 PDT)

 

I would also recommend getting deep cycle batteries like the Optima YELLOW top, Odyssey and Brail also make some nice batteries.