Question on transfer switch with inverter and generator

I installed an outlet from the inverter (3000W) in the basement next to the shore cord reel. When boondocking I plug the shore cord into the outlet, this give power to the whole rig. I use a transfer switch wired with the shore in and the generator in and the rig out. I use 2 relays first gets picked when the inverter is on which opens the 120V feed to the converter. Thus inverter = no power to converter. The second relay is picked when the generator is on and opens the above circuit. Thus generator = converter power on. Sounds complicated but is not. I use a small 12V wall transformer plugged into the inverter to power the circuit. The first relay has a 12V coil and the second has a 120V coil. Absolutely reliable and no memory required.

Housted

phemens wrote:

Getting older and lazier, there must be an easier way, right?

There is, but it won't be cheap !

Replace what you have with a combination inverter/charger/transfer switch like a Samlex Evo !

These are actually designed to be used with a permanently mounted generator, but a portable generator will work if you have some place to mount it.

Throw out your current converter. Connect the DC distribution panel directly to the battery bank (via a fuse of course). All connection, shore power, generator power, solar power from the charge controller, house battery and AC out, go to this one unit ! If you have shore power, it uses it. If not, it uses battery/inverter. If that is insufficient it can (optionally) start the generator.

There are probably other manufacturers of the same.


EDIT : Samlex does make a smaller, less expensive, inverter/charger/transfer switch without a separate generator input (so the generator would plug into the exterior shore power cord) but it is only rated at 10A of AC "pass thru" current.

phemens wrote:
Thanks for the inputs. The converter I have now is a Boondocker (from Best Converters) that has an on/off switch and is not hardwired. I guess I will try the double conversion route and see how that goes, seems simple enough - I had installed an AC plug right next to the converter anyways, so i’m assuming I can just plug into that when on shore power (rather than to the factory installed outlet behind the distribution panel, only advantage there is it’s on its own breaker).
The combined inverter charger intrigues me for later if I step up to a higher wattage model. How does it handle the generator? If I get a remote start model like a Champion 3400 at some point, can it be wired to auto start the generator when it drops below a certain voltage?

You must not have the 2000w version with the 55 amp charger but just the inverter, or this would be even more fun!

Auto start gen would not be very popular when it fires up at 3 am in a park where gen hours start at 9 am. The inverter is supposed to do the 120v stuff in silence until gen hours let you recharge the batteries. I do not understand how an RV can use an auto gen start feature in any likely scenario.

The extra work in manual transfer is not much extra when you have a portable generator.

It is different with a 5er from a MH what the opportunities are for all this as to where the shore cord , converter, and batteries are.

You only need the converter when you are on shore power or on generator, so the converter can be portable too. The converter is only ever plugged into the Rv's receptacle when you are on shore power (mostly only at home) It plugs into the portable gen when you use that ( not often ) the rest of the time it is unplugged. You just need a place to stash the portable converter and the portable generator and your extension cord.

The real issue going without enough solar and that big battery bank is how to recharge it when it gets low when you only have a 2000w gen which can only run about 60 amps worth of charger. I have not figured that one out yet for my own case.

With the 5er it was easier. 3000w gen in the truck and big amp portable charger(s) onto the battery bank up front in the 5er. Can't do that with the Class C. That is why they put those built-in gens in MHs and use transfer switching. (Our MH does not have the built-in gen, and can only carry the 2000w size portable gen, so we have a similar situation to the OP's.)

The OP can do this with his Boondocker, having a 5er and a truck. Gen in truck.

A solution using two transfer relays:

Thanks for the inputs. The converter I have now is a Boondocker (from Best Converters) that has an on/off switch and is not hardwired. I guess I will try the double conversion route and see how that goes, seems simple enough - I had installed an AC plug right next to the converter anyways, so i’m assuming I can just plug into that when on shore power (rather than to the factory installed outlet behind the distribution panel, only advantage there is it’s on its own breaker).
The combined inverter charger intrigues me for later if I step up to a higher wattage model. How does it handle the generator? If I get a remote start model like a Champion 3400 at some point, can it be wired to auto start the generator when it drops below a certain voltage?

Not 100% automatic, but . .

When camping, plug the shore cord into the inverter and turn off the converter. Run an extension cord from the generator to a hardwired battery charger or second converter to maintain the batteries.

Not camping, plug in shore cord and turn on primary converter.

You can do a sub-panel or power just the individual branch circuits to power what is needed.

I went with small transfer switches on just the branch circuits I need. Only issue is the fridge is on one of the branch circuits and needs to be set to propane only.

https://www.donrowe.com/KISAE-TS15A-Automatic-Transfer-Switch-p/ts15a.htm

the auto OFF converter part, means doing some rewiring and a sub-panel

if you can remember to turn off the converter circuit breaker

the switching between the inverter and the generator can be done by
by DIY build
PUT a TS switch in a weather proof box (plastic ammo can?)
need too male plugs, one female outlet, and right size cord
female outlet is for the RV shore cord
(2) male cord ends, one to connect inverter, one to connect generator
default is for inverter to be connected, switches to generator when genny is started

phemens another route is to use a hybrid inverter/charger. They come with a transfer switch and 125 amp charger. It makes short work of recharging, which is no bad thing when generator charging.

Love your battery bank. Green eyes here!

What BFL13 is suggesting is called "double conversion". I used to do it LOTS when I had a stand alone inverter (2500 watt MSW). I would only power the converter. I did add an additional shore power cord for just the converter. I had an additional outlet on the auxiliary shore power cord so I could run an 800 watt heater as well as the converter, without tripping the shore power breaker.

phemens wrote:
ok, misread something there. You are running a cord from the converter straight to the generator (unplugged from AC panel in trailer)? I guess that could work too, I would have to find an easier way to plug the converter back into the breaker box to get the shore power (or I guess just run extension cord from converter to house?)

As above except I have a plug- in cord on the converter, not hard wired. If hard wired you would have to re-wire it. Don't need a 30a shore cord, so the #12 is fine to the gen or pedestal to run the converter, and the inverter runs the MW ok on its 15a receptacle. Just needs the usual "power management" not to run everything at once.

We never need air conditioning, so that is the deal breaker for this method if you do.

Of course if solar is not happening, you can use the inverter's remote on/off to only have that on when actually running something 120v

Except get on sale for half this

https://www.princessauto.com/en/detail/15-m-12-3-triple-end-contractor-grade-extension-cord/A-p8035685e at times.

also they have the three foot one as the short piece. You don't need all three but they don't have a two.