There is the question of whether the charging system is up to the task of driving the load (inverter driving various equipments battery chargers/power supplies) while the engine is on. This speaks to whether the current alternator is up to the task and depends on the load of the truck itself puts on the electrical system plus whatever load the inverter adds while running AC accesories. You have to add up the truck load with whatever the inverter is powering and consider the inverters conversion efficiency then compare that to what the alternator is capable of providing.

Another important factor is whether you are running the inverter while the engine is not running and how much you plan to do it. If you want to do it much at all I would seriously consider an isolated deep cycle battery to power the inverter with. The reason is that starting batteries are simply not designed to deep cycle and can quickly be ruined by trying to use them this way. A deep cycle battery is designed to discharge up to 50 % (ie 50% ~ 12.0V or so and 100% ~ 12.8V or so) and still offer long service life. A couple 50% discharges on a starting battery could easily turn it into a boat anchor.

You really need to consider all the loads and when they will be run. There is a science to it which requires a bit of consideration on your part to ensure good service life and reliability. The real answer to your question as stated is not enough info. Tell us the loads sizes (should be a sticker on each power supply stating power draw, and also a efficiency rating of the inverter) and the expected usage, ie engine on, off or both for example, and we may be able to really help.

 

Will a deep cycle battery take a continuous charge like a regather battery?

 

I'm not sure a deep cycle could provide the cranking amps needed to start the truck.

 

I was just going to use it as a extra. But was told that you could not put a charge to it all the time like a alt would do

 

You charge them just like you charge a starting battery.

 

Thats one reason why you isolate them and have an starting battery and a deep cycle battery. Your right. It's best to leave each battery type for doing what it's best at. The starting battery should be for running the truck only and the deep cycle should be for running the accessories only. That's the best way to wire it IMO.

It's how nicer RV's are set up.

 

not sure if this is exactly how a friend of mine did it but he had 2 batts...in between he had a one way power box......coming off of that battery going into his cab he had a power inverter to go to his fridge cooler laptops and so forth.....this way he could use that battery for his 120v stuff but would not use any of the charge for normal running of truck.....his battery was a deep cycle marine battery and he used that setup for years on same battery without destroying marine battery

 

Your trucks charging system wont harm a 12V deep cycle battery unless it's voltage regulator is fried.

Edit it is some of those old school stand alone single stage chargers you have to watch out for. They will boil off the water in your batteries quick when left charging too long. Best solution is buy one of the new CPU controlled 3 stage battery chargers. Those are designed to charge faster than the old school chargers and to save the life of the battery by tapering off the voltage as the battery approaches fully charged.

 

I am unable to get the exact specs on my cell phone charger because my inverter is inside my dashboard in the space behind the cupholder. Most cell phones have ~3V batteries, so I'd assume the charger draws around 1 amp @ 120V. The Bluetooth adapter draws now more than 500mA @ 5V DC as it is USB.
The inverter specs:
Continuous Power: 400W
3.48 Amps @ 115V DC
~30 Amps @ 12V DC

I think I will get an Optima deep cycle and wire it in using an isolator and power all accessories from the deep cycle battery to save strain on the starting battery.