Add Inverter & batteries to 3914... comments?

[MystrMagic]

Recently bought a new, 2009 model year 3914 and was considering adding solar panels and batteries because I have previous experience with solar systems. However, learned that my tow vehicle actually charges the battery in my 3914 when driving down the road, and the generator charges it at night so I decided it would be a waste of money and work to install solar panels. Figured I would simply increase my battery capacity and proceed with adding an inverter.

Here is why I want an inverter (in a nutshell). The generator puts out 110v ac for all appliances (including the furnace and airconditioning) and all the lights work directly off dc. I can envision times when I may want to sleep with a small fan at night (instead of the AC or furnace) and I don't want to run the generator all night just for a small fan. (Hate to burn all the expensive gasoline unecessarily, not to mention, there are those pesky "no generators after 10:00PM" rules in some places.)

In thinking about this, I have come up with a plan to add a 2000w inverter with a remote on/off switch. This will be installed next to the generator and will be tied into the main leads coming off the generator. This way, the inverter will be off when the generator is running and there will be no interference or danger of any kind. When the generator is off I can remotely (from inside the living quarters) switch the inverter on (which would draw its power directly from the battery bank) and it would supply power to all the electric outlets overnight. Would have to be careful not to overload the system and don't expect it to run the AC or furnace as they would draw too much power.

But that would allow me to plug any small appliance (i.e. fan, TV, computer, etc.) into any available outlet. Can also plug my x-10 security system into the outlet throughout the night, again without running the generator.

If I do run the generator it would refresh the batteries and, of course, during daily travel my tow vehicle would refresh them.

Before any of you go into great detail about how many watts, watt/hours, deep cycle issues, etc., are involved, I am already familiar with all these issues and limitations from my previous solar background. I have no problem monitoring my power usage to prevent draining everything.

But this is my first RV and I would hate to "blow it up" by accident.

So my real questions are, 1. Does anyone have any comment about the safety or effectiveness of tying directly into the generator output lines?
2. Has anyone else actually done anything like this?

Appreciate any comments or opinions.

 

[boatdoc]

Hi Magic, Your furnace is 12VDC so it does not care about an inverter. If you tie the inverter into the 120VAC lines of the genny you WILL backfeed the inverter and most don't like this and you will get a weird electrical smell from it," fried".
Good luck

 

[Lance & Jo]

I have used an 1800W Heart inverter with built in 30Amp charger connected to both shore power and my generator for the last 12 years with no problem. Think you will find that most major brand (ie Heart, Prosine, Zantrac, Outback) large inverters have an input power sensing relay to turn the inverter off when shore power is available. Might also suggest if your battery bank is going to be very large you look at the inverter/chargers from he major brands.

 

[caissiel]

I have installed the Inverter on on dedicated line going to the slide plugs. It supplies all the living room plugs and the fridge. I just isolate the plugs from the fuse panel with a 3 way switch and direct them from the inverter that is connected directly to the Batteries. The 3 way switch can select either from the fuse panel or the inverter. The inverter has no chance to be overloaded unless there is a major load on the living room plugs. I once forgot to put the fridge to the propane selection and ran it all night with my 1200 watt inverter. It operates my 32" TV, the satellite box and the portable computer.

 

[palebluedot]

I don't see any problem as long as you isolate the generator output from the circuit when you have the inverter switch activated. You don't want to backfeed current into the generator output. A DPDT switch would accomplish both at the same time.

 

[MystrMagic]

Thanks for all your feedback everyone. Since the outputs of both the generator and inverter will be connected together and tied into the main distribution point, each one will supply power everywhere. As I understand it, if the generator is on and the inverter is off, there is no current going into the inverter because there is no where for it to go. And similarly, when the generator is off and the inverter is on, there is no current going into the generator because there is no where for it to go. As long as I never turn them both on at the same time I should be ok.

Anyone see a problem with my understanding of that?