Is a "battery bank" possible

Ok first yes you can run your items off an inverter. The batteries don't charge with an inverter but from the alternator. You don't need more batteries you have them. As far as keeping them charged it will depend on a lot of factors How much you use. How long etc. oh and charged for ideling? Yeah ok next company! How do you sleep if it's 20 degrees in the winter or 90 in the summer? Do you have an apu? If so it should have an alternator to keep your batteries charged. Unless it's an epu witch suck!

 

Possible? Yes, safe? not really. You would need to hardwire your batteries into the charging system of the truck, and everything would need to be secured against movement and protected against anything touching terminals/wires and shorting something. A shop could get it done safely but I doubt most companies would go for that idea. A driving tossing a couple batteries in the bunk and running some jumper cables is a fine way to end up with a truck burned to the ground.

Oh, and you would be looking at some pretty significant weight as well.

 

To directly answer your question, sure it can be done. However (as someone else said) you would charge from the alternator, not the inverter.

Do you have an inverter now? What size is it, how much does it draw from your battery under the size load you plan to have?

How much power do you need and for how long do you need it? Without knowing that there is no way to determine the size of the battery bank necessary to accomplish the goal. To small of a bank and you will not be happy and to large of a bank and you will have unnecessarily spent to much money.

How do you do it? Pretty simple. Once you have determined how many and what size batteries you need the next step is to find a place to safely mount and secure them. There are many options but you really do not want them inside the cab or sleeper unless they are 100% sealed and gasless, (like an AGM type battery). You will want to be sure to use deep cycle batteries unless you own stock in a battery company. (Normal "starting batteries" will not last in the type of operation your wanting and you will be frequently replacing them).

Once the batteries are safely mounted you will need to run the proper size cables (these will be very large) to your inverter. You will of course need a properly sized fuse or circuit breaker in the positive lead mounted as close to the battery as possible.

That will run the inverter. Now you need to find a way to charge the bank. The simplest way is to run a properly sized cable from your factory batteries to your bank. You will need both a power and ground. You will need to put a properly sized fuse or circuit breaker on EACH END of your posative charge cable, again as close to the batteries as possible. To be clear on this... At your factory batteries you need to fuse the charge cable. At the other end where it attaches to your bank, you need another fuse. That way, if the cable shorts out to ground both fuses blow thereby disconnecting ALL batteries from the cable.

OK, not so fast, your not done yet. If you leave the new system like that when you shut the truck off ALL the batteries (your new bank AND the factory batteries) will be powering the inverter and be drained. What you need is a way to disconnect the charge cable from the factory batteries when the truck is off so that only your bank is being used by the inverter leaving the factory batteries fresh and ready to start the truck.

There are a few ways to do this.
1) pull a fuse from either end of the charge cable when you shut the truck off, put it back after you start.. this works but is a lot of trouble...
2) manual switch, like they use on boats. Better but still manual, you'll eventually forget to shut it off and drain ALL your batteries and the truck won't start, or you'll forget to turn it back on and your bank won't charge.
3) battery isolator. Allows a single input with 2 seperate battery banks. In your case you would only be using half of the function of this device but that's OK. The unit is 100% automatic so you never forget to turn it on/off. Problem with these things is they use cheap diodes in their construction and cheap diodes cause a drop in voltage. This means your bank will never truly get fully charged.
4) continuous duty, high amperage rated relay. You connect the activation circuit of the relay to the accessory system of your truck so when the truck is on, relay is on. Truck is off, relay is off. When starting truck, relay is off, (you do not want your bank to be involved in Trying to start the truck).

If EVERYTHING is done properly, (proper size battery bank, secure mounting of everything, proper wire size, proper fuse size, proper placement of all fuss, proper terminals on all wire ends, proper wire routing, all wires run in some sort of protective loom) your system should be safe and provide you with the functionality your looking for.

Hope this has been helpful..

 

Why is this here?

 

Boredom

 

Just hook some jumper cables to the truck parked next to you

That's why the megas install those super easy to reach battery terminals

 

Well you would be better just to get a small 3000 watt honda generator and an extension cord through the window than to put in 120 to 160 pounds worth of batteries and the container they have to go in and the wiring and all the other safety stuff, mind you if the company won't allow it and you do it anyway, you can lose all of it when they fire you.

 

What you've essentially described is an EPU, and they're worthless. Find a company that has APUs, lets you idle, or allows a genset.

 

What the OP mentioned is a factory option on freightliner. I have one. But they go dead after about 9 hours. So on a 34 hr reset you spend a good deal of time idling anyway, to recharge them. A diesel powered APU is better. But of course, that option isnt available to the OP in a company truck. So I would agree with Ridgeline, and get a small generator. But keep in mind cheap generators don't create a proper sine wave, and thus can destroy sensitive electronics like computers and TV's. So make sure to research and get a good one. Some one more tech savvy than myself will probably elaborate on the sine wave issue for us.