Auto Transfer Switch Question

Greengas · Mar 10, 2018

So, as I continue my journey to get the Residential Fridge done (dropped the rig off today) I found out that the facility has not yet purchased the inverter (more on that later). Anyway, as I continue to read through past posts it seems that since I had the gen prep done as part of my initial rig purchase then I already might have an auto transfer switch installed and all I need to do is have the new inverter wired through that auto transfer switch. If so, that should save me some money.

So, is my thinking correct? Or, as usual, am I off base here.

danemayer · Mar 10, 2018

Greengas said:
So, as I continue my journey to get the Residential Fridge done (dropped the rig off today) I found out that the facility has not yet purchased the inverter (more on that later). Anyway, as I continue to read through past posts it seems that since I had the gen prep done as part of my initial rig purchase then I already might have an auto transfer switch installed and all I need to do is have the new inverter wired through that auto transfer switch. If so, that should save me some money.

So, is my thinking correct? Or, as usual, am I off base here.

Ronn,

If you have gen prep, that includes an automatic transfer switch. If you don't plan on ever having an Onan generator installed up front, you should be able to route the inverter output to the transfer switch. But like your shore power cord, the transfer switch has 2 incoming power legs. You'd need to run the inverter output into both legs to provide power to everything in the coach - similar to what you'd do if plugging your 50 amp shore power cord into a 30 amp receptacle using an adapter. The adapter takes the single hot wire source and splits it out to the 2 hot legs of your shore power cord. You'd need to do something like that coming out of the inverter, or you'd need an inverter that supplies output to 2 power legs.

Greengas · Mar 10, 2018

danemayer said:
Ronn,

If you have gen prep, that includes an automatic transfer switch. If you don't plan on ever having an Onan generator installed up front, you should be able to route the inverter output to the transfer switch. But like your shore power cord, the transfer switch has 2 incoming power legs. You'd need to run the inverter output into both legs to provide power to everything in the coach - similar to what you'd do if plugging your 50 amp shore power cord into a 30 amp receptacle using an adapter. The adapter takes the single hot wire source and splits it out to the 2 hot legs of your shore power cord. You'd need to do something like that coming out of the inverter, or you'd need an inverter that supplies output to 2 power legs.

Wait, let me get this straight. If the inverter is wired into the transfer switch (I have no plans of getting a generator) then the people doing the install won't have to rewire anything because the entire coach 110v will go off the inverter? Am I understanding that correctly? Oh, and I know I can't run the AC and all, but this will save me lots of bucks.

danemayer · Mar 10, 2018

Greengas said:
Wait, let me get this straight. If the inverter is wired into the transfer switch (I have no plans of getting a generator) then the people doing the install won't have to rewire anything because the entire coach 110v will go off the inverter? Am I understanding that correctly? Oh, and I know I can't run the AC and all, but this will save me lots of bucks.

Yes, as long as the inverter feeds both power legs that go into the transfer switch, you can run any 120V AC device in the coach without any other special wiring.

Doing things this way you will need to manually shut off the circuit breaker for the Power Converter. If you don't, the battery/inverter will supply 120V AC to the Power Converter so that it can send 12V DC back to the batteries. The inefficiency will waste battery power. But if you forget to turn it back on when on shore power, the batteries won't get recharged. So you'll need some kind of reminder system.

And of course you'll have to manage power usage. Things like A/C units, microwaves, toasters, coffee pots, heaters, all use lots of watts and will run the batteries down quickly. So even though they will work, you will want to use them very judiciously if at all.

carl.swoyer · Mar 11, 2018

Greengas said:
So, as I continue my journey to get the Residential Fridge done (dropped the rig off today) I found out that the facility has not yet purchased the inverter (more on that later). Anyway, as I continue to read through past posts it seems that since I had the gen prep done as part of my initial rig purchase then I already might have an auto transfer switch installed and all I need to do is have the new inverter wired through that auto transfer switch. If so, that should save me some money.

So, is my thinking correct? Or, as usual, am I off base here.

If you purchase a new Inverter get one with a built in transfer switch. It's those times when you forget to flip the switch you're going to wish you did. I personally don't feel the need to power the entire rig. If you forget to turn the converter on and off your ither running down your batteries or not charging. A Magnum Inverter such as the Ms 2012 or a
Ms 2812 will give you everything you need for power and Charging. They both have pass thru technology ( no flipping breakers on and off) My Ms 2812 has I believe a 140 amp Charge controller great for bringing the batteries up quickly. My factory Charger is still wired to the panel but unplugged. If I have any issues with the Magnum Charging I simply plug the factory in and turn off the Magnum charger.

Sent from my XT1254 using Tapatalk

carl.swoyer · Mar 11, 2018

Greengas said:
Wait, let me get this straight. If the inverter is wired into the transfer switch (I have no plans of getting a generator) then the people doing the install won't have to rewire anything because the entire coach 110v will go off the inverter? Am I understanding that correctly? Oh, and I know I can't run the AC and all, but this will save me lots of bucks.

Your converter charger will also run unless you flip the breaker.

Sent from my XT1254 using Tapatalk

Greengas · Mar 11, 2018

Ok Heartland Family where so many are so much smarter than me on so many things, this topic included. I have today to get this figured out. I need to calll the shop tomorrow morning and say, here is the inverter I've purchased, here is how I want it installed. So, let's go

1. Realistically, I need the inverter to power the fridge, a second small fridge and an outlet or two. Having it power through all outlets sounds GREAT! But it seems there are drawbacks.
2. I don't want to be Penny wise and Pound foolish. But, I already have a charger and buying a new "Inverter Charger" again sounds great, but costs a lot more. But it does put the inverter though the entire rig vs just a few outlets. But the cost...
3. I want this as automated as possible. That's why I was looking at an inverter with auto transfer capability. If I understand this correctly, with this type of inverter it will be as automated as possible without buying a new inverter/charger but it will only power through the items I want. but, if all I have to remember to do is just turn it on and off am I making more of this than is practical?
4. So many choices on which one to buy. Yes, Magnum seems to be good but costs a bunch. I was looking at AIMS (I really like their combined control panel and on/off switch). Cost not too high and seems to have good reviews. Are there any other brands I should strongly consider (Power On, Xantrex, Sunforce, Go Power) and brands to stay away from?
5. Will the inverter need a "Hard Wire Port" if I do decide to wire it through my already installed auto transfer switch?
6. Is there a way to automate the process if I do just wire the inverter through my existing auto transfer switch?
7. Last question (I promise) is 2k the right amount? If I go with an inverter/charger should it be 3k just to be safe?

Here are some inverters I was looking at:
https://theinverterstore.com/produc...transfer-switch-12-vdc-to-120-vac-etl-listed/
https://theinverterstore.com/product/2000-watt-pure-sine-power-inverter/
https://solarknowhow.com/2000-watt-inverter/

If I should go with just a new inverter/charger (the most simple and fully automated method) here is one I was looking at: https://theinverterstore.com/product/65/

Here is the control panel I was looking at. I wonder if it will work with any inverter or just the AIMS: https://theinverterstore.com/produc...ith-lcd-for-aims-pure-sine-inverter-chargers/

Ok Oh Great and Knowledgeable Heartland Family. I'm relying on you! Guide me, Teach Me, Educate Me.

TedS · Mar 11, 2018

Rewire the converter input to the shore power side of the transfer switch so that the converter is only powered when you connect shore power. No need to remember flipping the converter breaker when running on inverter power.

Greengas · Mar 11, 2018

TedS said:
Rewire the converter input to the shore power side of the transfer switch so that the converter is only powered when you connect shore power. No need to remember flipping the converter breaker when running on inverter power.

Ok, let me make sure I understand this. I will need an inverter with an auto transfer switch built in. Then I send the "disconnect" the wires that go to the input of the existing converter and connect those wires to the shore power side of the new inverter's transfer switch.

Do I have that right? And if I do, it means that as you said, the process is now fully automated. Is there anything I lose by disconnecting from my current converter?

carl.swoyer · Mar 11, 2018

Greengas said:
Ok, let me make sure I understand this. I will need an inverter with an auto transfer switch built in. Then I send the "disconnect" the wires that go to the input of the existing converter and connect those wires to the shore power side of the new inverter's transfer switch.

Do I have that right? And if I do, it means that as you said, the process is now fully automated. Is there anything I lose by disconnecting from my current converter?

My Magnum Inverter ms2812 has one hot in and two hot outs. From the RV distribution panel run a hard wired line to the Magnum hot in. This step keeps the Magnum with a constant 120 volts in and allows it to detect the presence of absence of shore power and it will toggle switch between shore power and inverter power.
Now the two hot outs on the Magnum.
I selected two circuits from the RV distribution panel.
The living room gives me ac for both sides of the living room to include tv, coffee pot, outlet next to my chair and the other side next to the dear wife's chair.
The second one is the mbr. It powers the tv and a few br outlets.
I disconnected from the RV distribution panel both of these circuit breaker. I wired the wires from the RV to the hot 1&2 out of the Magnum. The wires at this point are not connected to the RV distribution panel.
The Magnum Inverter has pass thru technology and it will automatically without interruption allow AC, 120volts to both of the front and rear circuits. This is the safest way to get dry camp batteries and Magnum Inverter wired. No risk of for getting to flip the breaker on and off.
If you go with the Magnum they have a technical services division.
There customer service is the best. You will need a sub panel and a DC shunt. I believe that my shunt is 400amps.

Sent from my XT1254 using Tapatalk

carl.swoyer · Mar 11, 2018

Greengas said:
Ok, let me make sure I understand this. I will need an inverter with an auto transfer switch built in. Then I send the "disconnect" the wires that go to the input of the existing converter and connect those wires to the shore power side of the new inverter's transfer switch.

Do I have that right? And if I do, it means that as you said, the process is now fully automated. Is there anything I lose by disconnecting from my current converter?

On your factory converter,
I left mine wired to the distribution panel. All you need to do there is unplug it from the ac outlet. This is your back up Charger, just in case the charge from the Magnum ever fails. If at any time the Magnum fails plug the factory Charger back into outlet, and you are charging again.

Sent from my XT1254 using Tapatalk

Greengas · Mar 11, 2018

carl.swoyer said:
My Magnum Inverter ms2812 has one hot in and two hot outs. From the RV distribution panel run a hard wired line to the Magnum hot in. This step keeps the Magnum with a constant 120 volts in and allows it to detect the presence of absence of shore power and it will toggle switch between shore power and inverter power.
Now the two hot outs on the Magnum.
I selected two circuits from the RV distribution panel.
The living room gives me ac for both sides of the living room to include tv, coffee pot, outlet next to my chair and the other side next to the dear wife's chair.
The second one is the mbr. It powers the tv and a few br outlets.
I disconnected from the RV distribution panel both of these circuit breaker. I wired the wires from the RV to the hot 1&2 out of the Magnum. The wires at this point are not connected to the RV distribution panel.
The Magnum Inverter has pass thru technology and it will automatically without interruption allow AC, 120volts to both of the front and rear circuits. This is the safest way to get dry camp batteries and Magnum Inverter wired. No risk of for getting to flip the breaker on and off.
If you go with the Magnum they have a technical services division.
There customer service is the best. You will need a sub panel and a DC shunt. I believe that my shunt is 400amps.

Sent from my XT1254 using Tapatalk

Ok, I looked up your inverter and it runs, on amazon approx 1.5k. Then I will have to buy a sub panel and a DC shunt. I am sure that Magnum is an outstanding product and what you are recommending would be a great set up but it would cost me a lot more than I was considering spending on the inverter. Don't want to be penny wise and pound foolish but I was hoping to not have to spend this much.

Of course, if I'm missing something here, like I looked up the wrong part number, etc., then please let me know and I will feel appropriately sheepish.

markwilson · Mar 11, 2018

Greengas said:
So, as I continue my journey to get the Residential Fridge done (dropped the rig off today) I found out that the facility has not yet purchased the inverter (more on that later). Anyway, as I continue to read through past posts it seems that since I had the gen prep done as part of my initial rig purchase then I already might have an auto transfer switch installed and all I need to do is have the new inverter wired through that auto transfer switch. If so, that should save me some money.

So, is my thinking correct? Or, as usual, am I off base here.

Did your 2014 not come with a residential refrigerator? We have a 2016 Ashland with a residential refrigerator from the factory. It was also factory prepped for an Onan generator. We will never have an Onan installed in this rig. I ripped out the box (to make more storage room for possible battery additions later), removed the Surge Guard auto transfer switch (slash) surge protector, and purchased from Amazon the "Progressive Industries HW50C Hardwired EMS Surge & Electrical Protection- 50 Amps." The wires from the (now gone) transfer switch to the non-existent generator just rest in the belly of the rig (didn't bother removing them). Personal opinion; the Surge Guard was a piece of chattering junk.

How much are you wanting to power through the inverter? Just the fridge? No need to overspend if only wanting to power your fridge with it. Our rig came with the 1,000 watt Magnum CSW1012 Pure Sine Wave Inverter, and all it does is power our fridge. Either way, if you happen to have the same Surge Guard ATS you might consider going the same route. Why have a transfer switch in the coach if you'll never use it?

For boondocking, our Yamaha 2400 EF2400iSHC gets the job done. We do have an Inergy Kodiak lithium-ion battery pack to power our blender, electronic toys, TV, etc, when boondocking.

porthole · Mar 11, 2018

Ronn - penny wise and pound foolish ....... you get what you pay for when you start talking inverters. Plenty of people buy the HF stuff and make it work. Until it doesn't. When you look at all the variations of inverters out there, there is a reason why the Magnums cost what they do and many other similar brands are 1/3 to 1/4 the cost.

You have to look at the specs as well. The best inverters run about 90-92% efficient. So you get a 1000 watt inverter and before you plug anything in you are at 900 watts - before it starts to warm up, providing you supplied the inverter with properly sized battery cables. A non pure sine wave, inexpensive inverter may only be 70% efficient.

An inexpensive inverter claiming 90% efficiency is BS.

Pure sine waiver inverters will cost more because of the cleaner output they provide. And they tend to be of higher quality. There are more pieces to the puzzle.

I don't have my Cyclone transfer switch manual handy and do not recall if it is a standard type of relay or a latching relay. Standard relays need power to make the connection the opposite of their resting state. Latching relays use power to activate then stay that way until power is applied again.

If you are trying to use the trailer transfer switch, will your inverter even output enough without a load to make the transfer? For example, I have a 2500 watt Heart Interface inverter (very good marine inverter). At idle I cannot use a corded drill, it will not start. If I add a 40 watt bulb to the circuit I can run my drill.

How much do you really want to power?

You need to know this before you buy an inverter. If you want to run the fridge and maybe a couple of circuits I would not look at anything less then 2000 watts. With a built in transfer switch, and remote panel capable. The inverter is going to be buried somewhere, Ideally within 3' or so of the batteries, so you want a remote switch and or display.

I do not have a residential fridge yet, but I would guess my loads would be similar to what you are trying to achieve.

I had a 1800 watt xantrex inverter with a built in transfer switch. Was never satisfied with it. For one thing, the voltage sensor always read about .6 to .7 volts lower then actual. This caused the inverter to kick out prematurely due to the low voltage cutout feature (non adjustable, higher end inverters this is adjustable).

I am now using a Kaise 3000 watt pure sine wave, built in transfer switch inverter. They are not Magnum quality, but are a really good alternative.
Connected to the inverter my circuits include; living room - 32" flat screen, DirecTV DVR, DirecTV power inserter, BR player, bedroom - 30" flat screen, BR player, DirecTV genie.
In the garage I have a circuit to run my ice maker and Dometic electric cooler - freezer.

My AV electronics are always connected to the inverter. That eliminate spikes, surges and they always have clean power. My ice maker is usually on from the time we leave home until we return.

Don't cheat yourself now on the install. If you want a successful project you need to start with a decent inverter, proper batteries (plural), the correct size wire and proper quality components.

If your installer is waiting for you to tell him how to do it, maybe he ins't your guy.

Greengas · Mar 11, 2018

porthole said:
Ronn - penny wise and pound foolish ....... you get what you pay for when you start talking inverters. Plenty of people buy the HF stuff and make it work. Until it doesn't. When you look at all the variations of inverters out there, there is a reason why the Magnums cost what they do and many other similar brands are 1/3 to 1/4 the cost.

You have to look at the specs as well. The best inverters run about 90-92% efficient. So you get a 1000 watt inverter and before you plug anything in you are at 900 watts - before it starts to warm up, providing you supplied the inverter with properly sized battery cables. A non pure sine wave, inexpensive inverter may only be 70% efficient.

An inexpensive inverter claiming 90% efficiency is BS.

Pure sine waiver inverters will cost more because of the cleaner output they provide. And they tend to be of higher quality. There are more pieces to the puzzle.

I don't have my Cyclone transfer switch manual handy and do not recall if it is a standard type of relay or a latching relay. Standard relays need power to make the connection the opposite of their resting state. Latching relays use power to activate then stay that way until power is applied again.

If you are trying to use the trailer transfer switch, will your inverter even output enough without a load to make the transfer? For example, I have a 2500 watt Heart Interface inverter (very good marine inverter). At idle I cannot use a corded drill, it will not start. If I add a 40 watt bulb to the circuit I can run my drill.

How much do you really want to power?

You need to know this before you buy an inverter. If you want to run the fridge and maybe a couple of circuits I would not look at anything less then 2000 watts. With a built in transfer switch, and remote panel capable. The inverter is going to be buried somewhere, Ideally within 3' or so of the batteries, so you want a remote switch and or display.

I do not have a residential fridge yet, but I would guess my loads would be similar to what you are trying to achieve.

I had a 1800 watt xantrex inverter with a built in transfer switch. Was never satisfied with it. For one thing, the voltage sensor always read about .6 to .7 volts lower then actual. This caused the inverter to kick out prematurely due to the low voltage cutout feature (non adjustable, higher end inverters this is adjustable).

I am now using a Kaise 3000 watt pure sine wave, built in transfer switch inverter. They are not Magnum quality, but are a really good alternative.
Connected to the inverter my circuits include; living room - 32" flat screen, DirecTV DVR, DirecTV power inserter, BR player, bedroom - 30" flat screen, BR player, DirecTV genie.
In the garage I have a circuit to run my ice maker and Dometic electric cooler - freezer.

My AV electronics are always connected to the inverter. That eliminate spikes, surges and they always have clean power. My ice maker is usually on from the time we leave home until we return.

Don't cheat yourself now on the install. If you want a successful project you need to start with a decent inverter, proper batteries (plural), the correct size wire and proper quality components.

If your installer is waiting for you to tell him how to do it, maybe he ins't your guy.

Porthole, thanks as always for your detailed guidance. I don't mind spending the money if that is what needs to be done. As for my installer, he is not asking, I was more in the mode of I want done what I want done. He has done many of these and I've talked to folks he has done the work for and they are all very happy, so I believe I'm ok there. I am looking at a 2k or a 3k (better over kill then no enough) inverter. As for batteries, I just purchased 3 Group 31 AGM 12 volts. Each rated at 105 amp hours so I should be ok there as well. I know 6 volt would be better, but... And I know that the only way to go is pure sine wave, no question there at all. (at least I'm sure of one thing)

As for the wire, what I've read is somewhere between 0 and 2. As for location, my inverter will be about 1 foot from my batteries so I should be ok there as well (hey, what do ya' know, I'm good on 2 things).

If I am reading your set up right, you've run just about every circuit that runs anything electronic direct to your inverter so it will provide protections, etc. I already have the Progressive Industries in-line 50 amp system so that should help for spikes, etc., as well.

I tried looking up the inverter you have and can't find it. Can you provide a link.

Again, thanks so much. I really do appreciate it. (if electronics was only as easy as woodworking for me this would be a breeze!)

- - - Updated - - -

markwilson said:
Did your 2014 not come with a residential refrigerator? We have a 2016 Ashland with a residential refrigerator from the factory. It was also factory prepped for an Onan generator. We will never have an Onan installed in this rig. I ripped out the box (to make more storage room for possible battery additions later), removed the Surge Guard auto transfer switch (slash) surge protector, and purchased from Amazon the "Progressive Industries HW50C Hardwired EMS Surge & Electrical Protection- 50 Amps." The wires from the (now gone) transfer switch to the non-existent generator just rest in the belly of the rig (didn't bother removing them). Personal opinion; the Surge Guard was a piece of chattering junk.

How much are you wanting to power through the inverter? Just the fridge? No need to overspend if only wanting to power your fridge with it. Our rig came with the 1,000 watt Magnum CSW1012 Pure Sine Wave Inverter, and all it does is power our fridge. Either way, if you happen to have the same Surge Guard ATS you might consider going the same route. Why have a transfer switch in the coach if you'll never use it?

For boondocking, our Yamaha 2400 EF2400iSHC gets the job done. We do have an Inergy Kodiak lithium-ion battery pack to power our blender, electronic toys, TV, etc, when boondocking.

Residential was not offered when we got our Rig (purchased in Jul 2013) so... Really wish it was. And, about a month after we took delivery, they came up with the upgraded axle and disc brake option. Oh well. We also have the gen prep and I had the same progressive industries system installed that you have as well. We don't own a generator of any kind because we very rarely boondock and when we do, it is only for one night so I'm hoping that 3 Group 31 AGM batteries will be able to keep the fridge going until we start driving the next day.

If I'm understanding your comments, you took out the installed auto transfer switch. Is that correct? So your fridge is the only thing wired to your inverter. So do you need to turn anything on or off or does the Magnum have auto transfer.

If I do go with the Magnum it will be the 2000watt one at a minimum because I know I will have 2 fridges running so better safe than sorry.

porthole · Mar 11, 2018

Greengas said:
Porthole, thanks as always for your detailed guidance. I don't mind spending the money if that is what needs to be done. As for my installer, he is not asking, I was more in the mode of I want done what I want done. He has done many of these and I've talked to folks he has done the work for and they are all very happy, so I believe I'm ok there. I am looking at a 2k or a 3k (better over kill then no enough) inverter. As for batteries, I just purchased 3 Group 31 AGM 12 volts. Each rated at 105 amp hours so I should be ok there as well. I know 6 volt would be better, but... And I know that the only way to go is pure sine wave, no question there at all. (at least I'm sure of one thing)

As for the wire, what I've read is somewhere between 0 and 2. As for location, my inverter will be about 1 foot from my batteries so I should be ok there as well (hey, what do ya' know, I'm good on 2 things).

If I am reading your set up right, you've run just about every circuit that runs anything electronic direct to your inverter so it will provide protections, etc. I already have the Progressive Industries in-line 50 amp system so that should help for spikes, etc., as well.

I tried looking up the inverter you have and can't find it. Can you provide a link.

Again, thanks so much. I really do appreciate it. (if electronics was only as easy as woodworking for me this would be a breeze!)

If your guy has done plenty, he should be able to suggest to you what needs to be done based on your desires.

That said. 6 volt batteries 'may be better' but not necessarily. Personal preference.
You can buy 12 volt batteries they can easily surpass the typical 6 volt golf cart battery thing, but you better be prepared to drop a lot of coins.

Inverter supply battery cable - 0 or 2 gauge is too small

2/0 or even better would be 4/0 And if you are going 3K you want 4/0 battery cable.

I have a Progressive EMS 50 as well. Although an excellent piece of equipment to protect the coach, it does not do what my inverter will do, e.g. leave a constant clean power source for my electronics all the time. Including connecting and disconnecting shore power, power surges, and the ability to use those items when not connected or using the generator. Or even the gap of power when switching from shore power to generator or vice versa.

I forgot to add, I also have an outlet connected to the inverter so we can use the Keurig at a rest stop without firing up the generator.

This is my current inverter, although I purchased at a jobber rate so about $200 less

https://www.westmarine.com/buy/kisa...-wave-inverter-with-transfer-switch--15020837

Next rig will be different though. That will have the Magnum 3012, which is a hybrid inverter. Along with several extras such as trailer temp monitoring, low battery and auto gen start etc.

markwilson · Mar 11, 2018

Ronn, I agree with Duane when he says, "How much do you really want to power? You need to know this before you buy an inverter."

With the residential fridge, you need an inverter to run it; and only it, if you can live without all the other stuff when the generator isn't running. All the other 110v stuff in the coach is a luxury during boondocking time, more or less. For example, we use a coffee press and a small butane camping stove to get us going first thing in the morning before firing up the generator at a reasonable time to maybe use the microwave and/or induction stove for breakfast and more coffee (wife). If doing a breakfast smoothie in the blender I just plug it into the Kodiak and that gets us to lunch time without the need of other 110v "stuff" (in the mean time the solar panels go up and/or the generator is running to charge the depleted batteries). So the question is, how much weight in batteries do you think feasible to power all the extra stuff you imagine you'll be using while boondocking.

And maybe I'm preaching to the choir here ;-)

We have our fridge plugged into a timer box which is plugged into the inverter to power the fridge an hour on, an hour off while boondocking. The batteries are being drained continually so it's a weight/longevity conundrum; how much weight in batteries, and/or Onan generator, do you want to have as added hitch weight to extend the time in between the need to charge the batteries up again? I keep the Yamaha in the back of the truck, so either way (Onan or Yamaha/Honda/Champion) we have the added weight of gen/gas over the rear axle.

Boondocking, for two of us, has been mostly about water and black tank. We've had no problem staying in one spot off grid with just the fridge being powered by the inverter when on battery power (i.e., the batteries keep it going through the night and the next day is more solar collection and running the Yamaha generator as needed to charge them back up).

How long are you trying to go in between the need to charge the batteries powering stuff above and beyond the fridge? No need having an inverter to power all that stuff if you don't have the batteries (weight) to keep it all going.

porthole · Mar 11, 2018

Inverter output size? I use the same formula for running diesel engines, 80%. Works for me.

Example, if my 3000 watt inverter is running about 92% efficient that leaves me about 2760 watts. If I use my diesel number of 80% that leaves me with a viable 2200 watts of decent steady power with some reserve.

My diesel example. In the marine world, because most diesel boats are single speed transmissions they are rated differently then the automotive world.
Typically a boat will be "propped" to allow a certain engine speed under full throttle with a typical fuel, water and passenger load.
With my Detroit 6-71's, they had a design speed output of 2550 RPM under full throttle, full load. So you would set the prop diameter and pitch to give you that RPM rating.
Then you use 80% of that speed as your normal cruising RPM.

My optimum cruise RPM was about 2000 rpm.

Greengas · Mar 11, 2018

markwilson said:
Ronn, I agree with Duane when he says, "How much do you really want to power? You need to know this before you buy an inverter."

With the residential fridge, you need an inverter to run it; and only it, if you can live without all the other stuff when the generator isn't running. All the other 110v stuff in the coach is a luxury during boondocking time, more or less. For example, we use a coffee press and a small butane camping stove to get us going first thing in the morning before firing up the generator at a reasonable time to maybe use the microwave and/or induction stove for breakfast and more coffee (wife). If doing a breakfast smoothie in the blender I just plug it into the Kodiak and that gets us to lunch time without the need of other 110v "stuff" (in the mean time the solar panels go up and/or the generator is running to charge the depleted batteries). So the question is, how much weight in batteries do you think feasible to power all the extra stuff you imagine you'll be using while boondocking.

And maybe I'm preaching to the choir here ;-)

We have our fridge plugged into a timer box which is plugged into the inverter to power the fridge an hour on, an hour off while boondocking. The batteries are being drained continually so it's a weight/longevity conundrum; how much weight in batteries, and/or Onan generator, do you want to have as added hitch weight to extend the time in between the need to charge the batteries up again? I keep the Yamaha in the back of the truck, so either way (Onan or Yamaha/Honda/Champion) we have the added weight of gen/gas over the rear axle.

Boondocking, for two of us, has been mostly about water and black tank. We've had no problem staying in one spot off grid with just the fridge being powered by the inverter when on battery power (i.e., the batteries keep it going through the night and the next day is more solar collection and running the Yamaha generator as needed to charge them back up).

How long are you trying to go in between the need to charge the batteries powering stuff above and beyond the fridge? No need having an inverter to power all that stuff if you don't have the batteries (weight) to keep it all going.

Thanks so much for the info. Right now, I don't have a generator and am not considering one at all due to how little we boondock (one night every so often) and I believe the batteries I have, 3 group 31 AGMs should be good enough for what I need. I could probably easily get away with a 2000 watt inverter (a bit of over kill but not too much).

I like your idea of the fridge going on and off during the night. If it is not being opened it should keep cold so...

Thanks again, now I have to find out what you use as a timer and try to work that in. Will this odyssey never end!

- - - Updated - - -

porthole said:
Inverter output size? I use the same formula for running diesel engines, 80%. Works for me.

Example, if my 3000 watt inverter is running about 92% efficient that leaves me about 2760 watts. If I use my diesel number of 80% that leaves me with a viable 2200 watts of decent steady power with some reserve.

My diesel example. In the marine world, because most diesel boats are single speed transmissions they are rated differently then the automotive world.
Typically a boat will be "propped" to allow a certain engine speed under full throttle with a typical fuel, water and passenger load.
With my Detroit 6-71's, they had a design speed output of 2550 RPM under full throttle, full load. So you would set the prop diameter and pitch to give you that RPM rating.
Then you use 80% of that speed as your normal cruising RPM.

My optimum cruise RPM was about 2000 rpm.

Porthole. That inverter looks great. And it seems to do what I need it to do. As for a boat, we sold ours a few months ago (traveling during prime boating season so it just did not make any sense to keep something on a trailer that did not get used).

So, with that inverter wired in, and the fridge, mini fridge and another outlet or so wired to the inverter, there should be nothing I have to do, no cutting something on and something off, right?

TedS · Mar 11, 2018

Interesting to read:

http://www.doityourselfrv.com/rv-inverter-install-diy/

Auto Transfer Switch Question

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Well-known member

Member

Retired

Well-known member

Retired

Member

Retired

Well-known member

Well-known member

Similar threads