Add Inverter to 2011 Tiffin 35QBA?

[GARYMC74]

I have received my Tiffin 35qba and generally love it. More interior room that the 3 slide, 41' Dutch Star that we downsized from! But..... It did not have an “entertainment inverter to run the TVs. This means that if you wanted to watch TV say at a Walmart stop, it will run you about $2.00 an hour in gas costs!

My question:

I want to add an inverter for general use, using the existing a/c receptacles. I have installed simple inverter setups before but the AC output being available only at a power strip plugged into the inverter.
I'm pretty familiar with the load limitations of inverters and what you can or cannot run. I have added two additional 6v golf cart batteries for a total of four.

The 35 qba came with an Inteli-choice #9260 converter with a 60 amp, 4 stage battery charger built in. I want to add a 1000-1500 watt (approx.) modified sine wave inverter into the a/c circuit, making all the existing a/c receptacles hot but continuing to use the #9260 converter for DC and battery recharging. I realize that I can buy complete inverters with battery charger and transfer switch but they are VERY expensive and I would have to tear out what is already there (the #9260). We won't use this for extended dry camping. Mostly just for an afternoon or evening . Would use the generator (7KW) for any serious loads.

When I have asked local RV shops about this they tell me “no problem” (at $115.00 per hour) but they can't really explain how they would wire it! Has anyone had any experience with this or any thoughts or suggestions?

[RV Wizard]

My suggestion would be if you are not wanting someone that has the knowledge and skill to design (each coach and how the customer wants things) and you want to do this yourself is to start doing research on inverters as to how they work, are wired, and also how converters are wired as well. you will then be able to look at how your coach is wired and design how to install the inverter close to the batter bank, and incorporate it into the 120vac system. You may or may not need to install a transfer switch, depending on which inverter you choose to use. You may have to install a sub panel again depending on the inverter you install. You will have to install a switch (if converter is not on a separate circuit breaker) to turn off power to the converter or you will have a loop that will try to invert and charge at the same time. The research and designing will take long than the install.

[Max Hubrich]

Gary-

I did exactly what your trying to do.

I went the 1500W MSW route at first. I burned up the inverter and the small basement Freezer/Fridge I had installed in a basement bay. Some motors don't like a MSW signal. I then ended up with a 2000W PSW (pure sign wave) Cotek inverter.
It is a cool unit- I can run a small 150 psi compressor and the small freezer on it. The one I refer to via the link has a built in transfer switch and also direct wiring capabilities. I had also tried a smaller Cotek inverter, with the power output on a GFIC outlet, and then I ran into GFIC tripping problems- something about the "neutrals" in a motor home. With the inverter I have now, I had to install a transfer switch and I tied the one house circuit I have for the TV's and my basement power for the small Fridge/Freezer into that circuit.

It's been working great for two years now and we're in the RV about 10 months a year.

My advice is to install a PSW inverter and get pure power like "off the pole". Then make sure you can tie in to the inverter without using a GFCI receptacle.

These Cotek folks are great to deal with, and the design engineer will be glad to explain why the GFCI receptables don't work well in a installed inverter in the Motorhome's environment.

Your wallet will be a little lighter with this unit but the transfer switch being built in is a blessing.

Oh, one other consideration- try to place the inverter physically very close to the battery power source. They say not more than about 6-7 feet of very heavy copper battery cables.

Good luck,

[GARYMC74]

Mike: I don't have the AC electrical knowledge to try and wire this myself. My previous coach had an OEM 2000 watt Xantex inverter so I have had some experience with loads etc. My problem is that I can't find anyone that really seems to know how to do this in my area (Dallas or general North Texas area.

My MH is a 2011 Tiffin QBA Ford. The elec. system is pretty standard Gas coach layout. 50 amp, transfer switch, 9260 converter, I have added 2 additional 6v batteries.

The inverter would be needed for the following items

• * 3 Flat Panel TVs
  * 2 Directv DVRs
  * 1 DVD Player w/surround sound
  * Gas/electric Ref. (maybe)
  * Some AC outlets in BR & LR for computers , cell phone charger, small fans,etc.
  
  

[RV Wizard]

You can go here Inverter/Chargers and down load installation manual for a typical install. Hope you can find someone to help you out. If not you might call Tiffin and ask if they know of someone in the area.

[GARYMC74]

Thanks to all for the input! Especially RV Wizard.
I have decided to use an Xantrex XM-1800 which has a built-in transfer switch and set up for hardwire install. As suggested, I have done a little homework and understand a Little more how it will be wired. It is an MSW inverter but at 1/3 the cost of an equivalent PSW I think it will serve my
purpose. I say this having used a MSW 2000 watt Xantrex in my Dutch Star for eight years with no issues.

I do have one concern. When this MH is connected to 20 amp shore power (one leg) and I start or stop my 7Kw generator the AC stops just long enough to toggle the TVs off and cause the Sat. receiver to reboot. Will the transfer switch on the inverter keep this from happening?
Thanks, Gary

[RV Wizard]

If you are loosing enough house battery voltage from starting the generator to cause this issue, the addition of an inverter off the same battery bank will not correct the low voltage problem. Check the battery bank for condition, loose and/or corroded terminal connections. Also check the connections on the generator itself. Good luck and keep us posted.

[GARYMC74]

The battery bank is in good, fully charged condition. 4 New Golf cart batteries wired with #2 cable. This is happening when connected to home 110v ac power. extension cord. I haven't been able to see if it still does it when connected to standard rv 30amp input.

[GARYMC74]

Mike:
I'm wondering since the Gen.goes into a momentary "get up to speed" pause before actually switching to producing 110 ac, could this be causing this shut off? Could it be shutting off the shore ac before the Gen. begins to produce? Since I do not have an inverter (yet) to provide ac in the interim could this give me this "no power" moment?
Gary

[Ed-Sommers]

The simplest way set up a temp usage inverter is to put it where you can plug in your shore power cable into the unit. No rewiring required - just run heavy cables from your batts to the inverter and plug in the shore power, DONE, SIMPLE.

I personally would not try to use this for "Gas/electric Ref. (maybe)".

Oh, and make sure any batt chargers are turned off using this method.

Ed

[RV Wizard]

Gary, I have re-read your last question and wonder if you have a time delay once generator is started before the transfer switch is activated and load is connected to generator. There should be a time delay before connecting to allow the generator to come up to speed and warm up a little before load is applied. There will always be a small faction of a second when the coach is not connected to one of the two sources (provided bath are available) when switching to the generator. Truthfully, you should be switching the air conditioners and other heavy loads off when switching power sources and then back on after at least three minutes. Your inverter will switch so fast in the event of shore power loss that it should keep the TV;s and digital clocks on and from loosing time.