The RV I'm buying has an Automatic Transfer Switch that selects shore power or generator with preference for shore power. If I add a solar system is there an ATS that has three inputs (shore power, generator, or inverter)??? Or, do I just leave the present inverter wired as it is? The RV has a residential refrigerator and uses house batts through the inverter. Will's videos assume any solar system build would replace the existing generator. I want to keep the generator to run the AC units while boondocking.
Is there a 3-imput Automatic Transfer Switch???
- Thread starter ChuckE
- Start date
Not sure that you need it- it's my impression that you use the solar charge controller to balance the solar input between the batteries and the output power, or if you run the power directly from the batteries, there should be enough capability in the solar controller to max feed the system at peak sun and peak power usage. Either way, the auto transfer switch has the input from the inverter or land power, and that's it.
It will be interesting to read other replies. I'm learning, too.
It will be interesting to read other replies. I'm learning, too.
You must never allow, even for a fraction of second, an inverter's AC output to connect to another AC source e.g. shore or genset*. So generally you would only ever need a two-input ATS, one for your external AC source (shore OR genset) and one for your internal AC source (inverter). Most people achieve this by having one external socket where you connect either shore power or genset. Your ATS will then switch between external and internal irrespective of what the external source is.
Note: the ATS will have an interlocking system whereby internal can never connect to external, even under a fault condition ... or rather, it should have.
*unless the inverter is designed for this e.g. grid-tie
Edit: corrected typo.
Note: the ATS will have an interlocking system whereby internal can never connect to external, even under a fault condition ... or rather, it should have.
*unless the inverter is designed for this e.g. grid-tie
Edit: corrected typo.
Thanks for the reply. Actually I just came across the user manuals for the RV I'm going to buy and among them was one for the Furrion 50A transfer switch. In it was an alternate wiring diagram that used TWO transfer switches. The first ATS selected between shore power and generator and the second ATS used the output of the first as input 1 and used the large inverter as input 2.
The Victron Quattro has two input sources that it automatically switches between. Not cheap, though. Good luck with your project!
My camper has an integrated generator, so there is no socket. It does have an ATS to prevent damage if the gen is turned on while the camper is plugged into shore power.
I think I'll have to get another transfer switch when I install an inverter too, but it would be nice to replace the one that is installed with a three source ATS.
wouldn't it be more simple to wire an RV plug to your inverter and just plug your RV umbilical into your inverter, so grid/inverter could never possibly be connected at the same time. These are available from Home Depot for something like $50.
Eliminates the need to search for something that may not exist.
Worked for me anyway.
Eliminates the need to search for something that may not exist.
Worked for me anyway.
Michael B Caro
Solar Wizard
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- May 21, 2020
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- 1,194
buy a second automatic transfer switch. Send the selected power source from the first switch to the second switch and have that one choose between the power source you sent to it and your 3rd power source. I have a transfer switch that did 3 power sources but when it went bad after a number of years I couldn't find another one, so I went to the solution I just described. Has been working fine for 3 years now. I did later run across an Aims 3 way transfer switch used that I picked up just in case. It supposedly works but I have never tested it so not sure.
AMPINVT 3000W Peak 9000W Pure Sine Wave Power Inverter DC 12V to AC 110V. It includes a transfer switch but under 30A. I'm sure our host has a link to Amazon that gives him a small finder fee. Go to the recommended products part of the RESOURCES pages and then follow one of those links. Once on Amazon just look up the inverter.
JimStLaurent
New Member
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- Apr 19, 2021
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If anyone goes for the cascaded transfer switches, you'll need to think about including a 110V relay controlled by the inverter output to isolate the battery, preventing it from charging itself thru the inverter. That would be a sinful waste of stored power.
For educational purposes, the system below was never implemented. I opted to hard wire the inverter to two dedicated 110V circuits at receptacles at opposing ends of the coach.
For educational purposes, the system below was never implemented. I opted to hard wire the inverter to two dedicated 110V circuits at receptacles at opposing ends of the coach.
This is exactly what I did with my truck camper.
Sprinterman
New Member
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- May 10, 2022
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I was planning on doing this.. I have a class C with a wfco 55 amp distribution panel. I bought the a 2000w inverter and trying to have the inverter run everything without the need of propane. The problem is the propane refrigerator still needs a 12v source, as well as the slide, lights and others I am sure. All I want to turn off is the charging of the batteries from the converter. I am looking for the solution. All I can figure is wire the 12 volt distribution directly to lithium house batteries, and the converter would only charge the batteries. I already have a transfer switch for the generator and the shore power. I was going to install another from those two sources and the inverter. I have seen some people say put a subpanel, but looking for advice. Thanks in advance!
fmeili1
Solar Enthusiast
This is exactly how I've done it in my RV. It works great - the relay is key here!
I used a Victron Multiplus in my MotorHome - it is an inverter/charger and works VERY well. Upstream of the inverter is a transfer switch to switch between grid & generator.
One very important thing to check is that the inverter is handling the N-G bonds correctly (Neutral-Ground Bonds).
You must have one (and only one) place where the neutral and grounds bond - usually at the power source.
When on grid the grid has a N-G bond.
When on generator my generator has a N-G bond. My transfer switch switches the Neutral wire along with the hot, so it opens the generator’s bond when the generator is not running.
The Victron Multiplus has a transfer switch built in, and it open and closes the N-G bond appropriately. That way there is only ever one bond point.
There is several ways of wiring everything correctly- please pay attention to how the equipment you are considering handles it.
Good Luck
One very important thing to check is that the inverter is handling the N-G bonds correctly (Neutral-Ground Bonds).
You must have one (and only one) place where the neutral and grounds bond - usually at the power source.
When on grid the grid has a N-G bond.
When on generator my generator has a N-G bond. My transfer switch switches the Neutral wire along with the hot, so it opens the generator’s bond when the generator is not running.
The Victron Multiplus has a transfer switch built in, and it open and closes the N-G bond appropriately. That way there is only ever one bond point.
There is several ways of wiring everything correctly- please pay attention to how the equipment you are considering handles it.
Good Luck
SoggyShoes
New Member
I thought one of the great features of the Victron Multiplus and Quatro is that solar, battery, or shore power/generator can all supplement each other. So if solar or shore power isn't supplying enough power the other supplements it.
So the Multiplus only needs a transfer switch for the generator vs shore power. While the Quatro has the transfer switch built in to the unit?
@sunshine_eggo ? (Please help with knowledge of things blue.)
So the Multiplus only needs a transfer switch for the generator vs shore power. While the Quatro has the transfer switch built in to the unit?
@sunshine_eggo ? (Please help with knowledge of things blue.)
The Multiplus has only shore (or generator) while the Quatro has both shore and generator. In your situation you would want a Quatro, it will work flawlessly and it has the added advantage that if the load is higher than the grid or generator can supply at any one instance, that it will supplement from the battery. It will even charge the battery from shore power or generator, (if you want) while loads are below the max draw.
You can adjust the max draw in the Quatro through the app on your phone.
You can adjust the max draw in the Quatro through the app on your phone.
sunshine_eggo
Happy Breffast!
I hope you understand the power requirements of an absorption fridge are 5-6X the same-size compressor fridge. A typical 7.6 cu-ft absorption fridge will use 4-5kWh/day vs. a ~18cu-ft compressor fridge at about 1.5kWh/day. Our Keystone had one of the 12 cu-ft double door fridges, and it used >11kwh/day when not used, i.e., fridge on, nobody opening the door.
You're establishing relationships that don't exist, but you're partially correct.
If the loads exceed the AC input current limit, the inverter can use battery to boost the AC input to prevent overloading the source. This feature is called powerassist.
Solar is separate and simply charges/floats the battery supplying loads only if there's surplus PV.
At a ridiculous premium for that function.
As an owner of two Quattros, I vigorously disagree. I would pursue an upstream ATS unless I had no other choice.
Yep. PowerAssist.
Only if you purchase the VE.Bus smart dongle, which allows monitoring-only (no settings changes) within bluetooth range.
You can do the same and more from any device anywhere with an internet connected GX device.