I'm about to rewire my truck and its going to be hell. Want I need is something that will be sufficient enough to keep a deep cycle marine battery charged, run a 1000 watt amplifier, 3000 watt inverter (at times at full capacity), fullsize lightbar, 2-way radio, 3-12volt sockets...Can't think of anything else right now.

I need all of this tied together to save wire. What I have in mind is this and it might get confusing,
Run 2 ( hot and ground) lines off the main battery into the cab. Have a "T" splitter on both. 2 lines to my distribution panels for everything else and the other 2 to the deep cycle battery in the toolbox. What I would like is to have the auxiliary battery tied into the main for all operations and to help with the load, while able to use all the accessories at one time off both batteries if I really really needed to although I probably never will.

If I use the equation Amps = Watts / Volts, If I use 120V I only need 25 amps to run, However If I use it on 12 volt, I need 250 Amps. Well, I'm taking 12VDC to create 120VAC, Which do I need? According to this table; American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies I would need 00 gauge for chassis wiring. The wire length will be 20' max. What do I do here guys? I'm good with electrical but this has got me.....In order to charge the axillary battery, I've been told I need an isolator but then heard I don't. I need help, Lol.

 

Your calculation is correct, you will need 250amps(probably a little more than that) to run that 3000w inverter. You are also probably correct on the wiring size. So you see, all this power is not free.

The first thing you need to do is re-think what you are doing with all this stuff and how it will be used. What do you need this large inverter for? Also figure out what situations you will be in, and what you really need to run at the same time.

If you really need this large inverter, consider this the priority load, and design for it, since it will be so much larger than anything else.

I would use a isolator. Mount the isolator close to the battery up front under the hood, and split the charge wire from the stock alternator. Come off the inverter with 2 10 gauge wires, run to a 60 amp circuit breaker, and then run these two 10 gauge to the rear to the deep cycle battery or batteries. These are only charge wires, so they don't need to be that large. I suggested two 10 gauge in parallel, since the 10 gauge is easier to find and buy, but if you want to run one larger wire(around a 8 or a 6 gauge) that will work also.

Pick a spot for the deep cycle battery AND the inverter very close to the deep cycle battery. If you want more run time on the 120v, you probably need two deep cycle batteries. For the max life and performance, I would get two 6v deep cycle golf cart batteries and hook them in series for 12v. Use your very large wire to hook these batteries up and to run the VERY SHORT distance to the inverter.

With this system you can use the 120v, even with the truck off, and not worry about running the truck's battery down to where it won't start. This is also the best way to combine the performance of a deep cycle battery, with the starting battery of the truck.

 

I design systems similar to this somewhat routinely for motorhomes and some fifth wheels. Standard is a battery bank of four deep-cycle 6-volt batteries in series parallel connection with this size inverter. Ideally AGM so you can run em down without killing them. Without plenty of battery, you are going to running on empty fast.

I can't imagine this system with a single battery. By my calculations, given standard 100 amp hours,per battery, before recharge, you would only have about 15-20 minutes with a 250 amp discharge before a single battery was discharged below 50% (give or take depending on battery size).

How long are you contemplating this high a load on the batteries? I have actually blown the top right out of batteries under heavy load given the heat that is generated during discharge.

Clearly an isolator or solenoid is in order. I use solenoids which are remotely switched.

Alternator size is no less than 160 amps, often more.

You may want to explore how these systems are used in RVs.

Good luck,

Steve

 

The 3000w is the surge wattage of the inverter. I'm only getting one that is around 1500w with a 3000w surge. Need one with some power to run my on board air compressor and getting ready for hurricane season so I can run the fridge or anything else I might need to in a power outage. The truck would be running the entire time the inverter is on. I can run my 800w surge inverter for an hour with a small load and still get the truck to start. I think it only pulls what it needs and no more. I have a ton of 8ga. wire already. The truck alternator is already 160 amps. I know I'm going to most likely need a bigger one under a full load. Anyone know where I can see a schematic of a system similar to this? I do see what ya'll are saying though.

 

Alternator output is traditionally rated when alternator is cold. Once warmed up, output is much less than rating. In my book, 8 ga. wire = 40 amps, so be careful there.

There really isn't much to this. Alternator to isolator. Isolator to house batteries. Batteries to inverter fuse. Inverter fuse to inverter. I think that's about it.

Rule of thumb for RVs, inverters are not used for any appliance that heats or cools given amp such as electric heaters or air conditioners. When they are battery bank size goes to at least eight and more often ten of those hernia giving 125 pound batteries.

Given this is only for emergency use, wouldn't a small 2000 watt Honda or 2400 watt Yamaha generator be simplier? Eventhough I sell them, service them, and install them, I am not a great fan of inverter power for high loads. I think they work great for small loads. I was wondering if you have checked to see what your actual load will be?

I am sure others would disagree with me. Good luck,

Steve

Steve

 

I agree totally. Now that he has said what his intended use is, I believe a little stand alone gasoline generator would handle the load much better, and be way more efficient that running the truck engine and wasting all that fuel.

 

Given the input and budget, I have went to a small 1400w surge schumacker (sp?) inverter instead. It's not as big as I'd like but it will get the job done for now. It came factory with 8 ga. wire so that is what I'm running it with. Also charging the deep cycle battery with 8 ga. battery cables. Everything is running smoothly for now.
Thanks for the help guys.