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Topic: Help in adding an inverter/charger and transfer switch to a 1993 U225  (Read 531 times) previous topic - next topic

Help in adding an inverter/charger and transfer switch to a 1993 U225

My coach came from the factory with no inverter, just a converter and a transfer switch.
When I bought this coach I installed 500 watts of solar panels, a charge controller and a 750 watt inverter which currently powers 1 house circuit. They are is set up just like the attached diagram.
I have one 300 AH lithium battery on the way along with bus bars and figure this would be a good time to add (or at least contemplate adding) an inverter/charger and a 2nd transfer switch if necessary.
In doing so, I would then power all the house circuits with the inverter/charger instead of just the one circuit I am powering now. 
My questions are:
1. Do I need a 2nd transfer switch?
2. If so, using the attached diagram, where do I put it?
3. Where does the inverter charger fit into this equation?
4. Last but not least, i need recommendations for the transfer switch and inverter/charger.
Any other comments are welcome. I may or may not add more solar panels and batteries as part of this project.   
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #1 –
Slim,

I won't attempt to answer your questions in detail, because I'm not an electrician, nor do I pretend to be one.

I can tell you that our Magnum MS2812 inverter/charger includes a built-in transfer switch that passes through the AC power from shore connection or generator.  We have two AC circuit breaker panels - main panel and inverter sub-panel - both at the foot of the bed platform.  If we have shore or generator AC power available, everything in the coach is powered through both panels.  If the AC power source fails, then the inverter kicks on automatically (instantaneously) and sends AC power to only the inverter sub-panel circuits.
 
The two diagrams below are from the paperwork we got when the Magnum was installed.  The first one is the generic "typical" RV installation.  The second one is the "marked up" diagram showing how AM Solar in Oregon set up our inverter powered circuits. 

On our coach, the "AC Transfer Switch" shown in the first diagram is a Blue Sea Systems 9019 manual transfer switch.  See photo below.

Transfer switch questions

AC Rotary Switch - OFF + 2 Positions 240V AC 65A - Blue Sea Systems

I don't know if this stuff is helpful, but I'm just throwing it out there in case it gives you any clues to how you might proceed.


1993 U280 SE 40' WTBI, Build: 4359
C8.3 300hp, 6-Speed, Exhaust Brake
960 watts on the roof (6 x 160)
Sorento (or BOLT) on a Kar Kaddy SS
"Nature abhors a vacuum"

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #2 –
Thanks Chuck. It helps a lot. I'm not at the point of ordering anything and certainly not at the "measure twice, cut once" time for cables but a built in transfer switch like you have in your Magnum helps me get a clearer picture..
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #3 –
Do think about using marine ul1427 cabling as it does not support fire.  Li-ion cells can burn in extreme conditions. 
"Riding and rejoicing"
Bob
1997 U320 40' Mid entry, build 5132,  wtbi ce27, 4th owner
2007 Solara convertible
2 prodeco tech outlaw ss electric bikes

1095 watts solar
08 Ls 460 and a sc430
2000 Ford F-250 superduty 4x4

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #4 –
I'm very happy with the MultiPlus-II 2x 120V.  I've put these in both the coaches in my signature. I connect them between the auto transfer switch and the coach system. If I'm on shore power or generator power, the ATS picks one of those to feed into the inverter. The inverter will charge the batteries and pass power through to the coach. It will also make up for the difference in load if the coach is pulling more than the shore power can provide. I can set the shore power limit to 10A for example if I'm at a friends house without a 50A hookup. To the coach side of things, the whole system just looks like it has power all the time. everything functions just fine.

Bay Marine supply gives a discount to forum members and has been great to work with,
Chargers, inverters, and refrigerators
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #5 –
What 120 VAC devices do you want to be able to run off the new inverter?

That will help determine best way to wire it and/or if an inverter/charger with built in ATS would handle your needs.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #6 –
Quote from: wolfe10 –
What 120 VAC devices do you want to be able to run off the new inverter?

That will help determine best way to wire it and/or if an inverter/charger with built in ATS would handle your needs.
Good question Brett. Having been on shore power for the last couple of years has spoiled me a bit. I like running my Norcold refrigerator on AC but can switch to propane (or simply shut it off) if necessary while I use a toaster or the microwave. I also have a 1500 watt electric heater and a 200 watt swamp cooler. Other than that, just a laptop computer.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #7 –
Quote from: Dakota Slim –
Good question Brett. Having been on shore power for the last couple of years has spoiled me a bit. I like running my Norcold refrigerator on AC but can switch to propane (or simply shut it off) if necessary while I use a toaster or the microwave. I also have a 1500 watt electric heater and a 200 watt swamp cooler. Other than that, just a laptop computer.

Realistically, running the 1500 watt electric heater through an inverter off your battery would not be reasonable (would deplete the battery quickly and require lengthy recharge time). I would say the same about running the absorption refrigerator on 120 VAC-- not energy efficient.  Just leave it on propane.

The other devices you mention can be handled by the ATS built into most  inverter/chargers (VERIFY the model you are considering has "pass through feature").

Wire inverter/charger 120 VAC IN from the main breaker box.
Wire inverter 120 VAC OUT to the outlets you want to be able to power from the inverter.

If more than just outlets, wire inverter 120 VAC OUT to a SUB-PANEL and move hots, neutrals and grounds from the other circuits you want to run to the sub-panel.

Strongly recommend a pure sine wave inverter, not modified sine wave as many electronic devices are not "happy" on MSW.

Locate the inverter/charger on the next basement bay forward of the battery compartment-- short wire run from batteries but not in the same compartment with the batteries.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #8 –
Thanks for putting that into perspective Brett. I got along fine for years using propane for the refrigerator, my Mr. Heater Portable Buddy and the generator. I want to keep this as simple as possible but also set things up to make adding more solar panels and battery capacity an easy option.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #9 –
My coach came with a separate Converter and 1500W Inverter. Inverter is connected directly to the 12V batteries. When I changed to a 3000w Victron Inverter/Charger, I ran a separate house wire (3-strand, forgot what it's called...romex??) back to the plug the Converter was plugged into. That allows it to run when plugged in or generator is running.
AKA Chuck
1993 U280 40' WTB, Build 4345, CUM 8.3 "Falcor", 2010 Honda CRV TOAD (Spock), 970W solar on roof
Full-Time traveler between Quartzsite AZ, Longview WA, Ellendale ND, and Lake City SD
The selected media item is not currently available.

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #10 –
Quote from: Balcanthez –
My coach came with a separate Converter and 1500W Inverter. Inverter is connected directly to the 12V batteries. When I changed to a 3000w Victron Inverter/Charger, I ran a separate house wire (3-strand, forgot what it's called...romex??) back to the plug the Converter was plugged into. That allows it to run when plugged in or generator is running.

Would appreciate more information on this.

With a "smart" charger built into your Victron Inverter/charger, why would you want to power a "stupid" converter in addition to the Victron unit?

And, is your converter wired to a breaker on the main 120 VAC breaker panel so you can turn it on/off or to the OUT from the Victron unit?
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #11 –
I unplugged the converter (there was a separate outlet just for the converter, next to the unit). I just took power from that outlet to the AC IN on the inverter/charger.

There is a breaker on my 120V panel (#7) for the converter plug.
AKA Chuck
1993 U280 40' WTB, Build 4345, CUM 8.3 "Falcor", 2010 Honda CRV TOAD (Spock), 970W solar on roof
Full-Time traveler between Quartzsite AZ, Longview WA, Ellendale ND, and Lake City SD
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Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #12 –
Just to be clear, I don't have the inverter/charger on while plugged in unless I go a week without sun. The panels and the solar controller keep the house batteries charged up all the time. If I was in a garage plugged in, I'd just turn on the charger for the batteries and leave the system alone. Boondocking I just use the inverter when needed. I use a small inverter (600W) for my entertainment center so I only turn on the regular inverter for making coffee or using the microwave.
AKA Chuck
1993 U280 40' WTB, Build 4345, CUM 8.3 "Falcor", 2010 Honda CRV TOAD (Spock), 970W solar on roof
Full-Time traveler between Quartzsite AZ, Longview WA, Ellendale ND, and Lake City SD
The selected media item is not currently available.

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #13 –
OK, that makes sense.  That is, as long as the breaker and wiring from 120 VAC breaker panel to outlet and outlet to inverter are properly sized for the Victron unit.

That means being able to handle both the load of the charger section and a full load of the "pass through" feature.
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #14 –
Thanks for all the help on these questions. At this point I have the new 300AH battery in the coach and added buss bars to make things nice and tidy. I should add that the original diagram does not show the fuses I have between the controller and the battery or between the battery and the inverter.
I am going to stick with this arrangement for now but will probably swap out the 750 watt inverter with one capable of powering the toaster, microwave or (maybe) my pizza oven.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #15 –
Quote from: Dakota Slim –
Thanks for all the help on these questions. At this point I have the new 300AH battery in the coach and added buss bars to make things nice and tidy. I should add that the original diagram does not show the fuses I have between the controller and the battery or between the battery and the inverter.
I am going to stick with this arrangement for now but will probably swap out the 750 watt inverter with one capable of powering the toaster, microwave or (maybe) my pizza oven.

Definitely need to get that pizza oven powered. How does anyone camp without one?  ;D
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #16 –
Quote from: kgrover –
Definitely need to get that pizza oven powered. How does anyone camp without one?  ;D
Foretravels come with generators!
And the pizza oven does a much better job than the gas oven.
1993 U225 Build #: 4285
500 Watts Solar
Honda CRV AWD
Former 1981 Foretravel Travco
Retired, Full Time Off Grid Snowbird

Re: Help in adding an inverter/charger and transfer switch to a 1993 U225

Reply #17 –
Quote from: Dakota Slim –
Foretravels come with generators!
And the pizza oven does a much better job than the gas oven.
My camping buddies just got one that is propane powered. He was looking in the opening as he was trying to light it as the flames shot out and almost too off his eyebrows.  Made great pizza.
1991 U300 Side Aisle 6V92 Silver #3897
2004 U320 40' #6246