Question on inverter/charger AC backfeed

Which is it? An inverter or an inverter/charger?

An inverter/charger has the charger built in so no back feed issue.

An inverter could be "whole house" where everything 120v in the RV will run off the inverter. In that case you must shut off the converter (various ways to do that) One way to do whole house is just stick the shore power cord into one of the inverter's output receptacles via adapters.

OR, you can do a sub-panel off the inverter so it only runs the 120v things you want it to where the converter is not on that sub-panel.

Yet another way is to give the inverter its own battery bank and run the rest of the 12v things off another battery bank. Now there is no back feed because the converter only charges the battery bank the inverter is not on. But now you need another charger to recharge the bank the inverter is on. This charger is powered straight from the generator or shore power.

You can set things up all sorts of ways and change things around later as you discover new ways to do things. ( So don't nail anything down in case you want to move it on your next reno. :) )

The inverter generally will have a transfer switch built into it, or associated with it. It doesn't send power back to the electric panel to power circuits; rather, there are some circuits that are connected through the inverter, and it either sends power from the electric panel on to them (when not inverting) or powers them itself (when inverting). Often they also have one or more circuit breakers of some sort on the inverter for these circuit(s), so you might have for instance a 30A circuit feeding the inverter/charger and a pair of 20A circuits coming off of it (which, naturally, could not be simultaneously loaded to 20A in this example).

Any system that backfeeds the electric panel is likely to be dangerous, as it would leave the shore power cord live when it's unplugged. A built-in generator with a transfer swtich is okay because of the transfer switch, which disconnects the shore power cord when the generator is supplying power; but if the generator is not running, the shore cord is connected to the electric panel and any power present there would be exposed at its plug.

I should clarify that my plan is to have the inverter wired into the panel so I can run anything on shore power or battery bank/solar.
I suppose you should just switch off the second leg breaker but it sort of squashes the whole automatic switching thing. The only make I know of who has a full 50A passthrough is Go Power but I've read mixed reviews on them.

One hundred percent off grid useable requires a generator for A/C. When A/C isn’t needed, an adequate solar system will run everything else and is preferable IMO. Do you have any plans re solar?

JaimeTheLimey wrote:
if you run one leg of the 50A service to the inverter and the second leg directly to the panel, when the inverter is running wouldn't you be backfeeding the second leg.

I can't answer, but I can suggest you get a '50a' inverter.

JaimeTheLimey wrote:
Hi all. New member here about to pickup a Grand Design this weekend and I'm already planning out upgrades to make the rig 100% usable off grid.
I'm versed in electrical but the whole inverter/charger thing is new to me and I have concerns with the split phase nature of them.
Can someone correct me if I'm wrong, but if you run one leg of the 50A service to the inverter and the second leg directly to the panel, when the inverter is running wouldn't you be backfeeding the second leg.
Seems that unless you kick off the breaker to that leg your shore power connection will be hot. My old Lance 5th wheel only has a male connection so that would be a major concern.
Any input your have is appreciated. Thanks.

No back feed. It all depends on how the inverter is wired. Inverter can power just circuit hooked to it OR it can go back to a split buss panel and feed just a few things in 1/2 of the panel.

I think the newer high end all electric coaches it can feed the whole panel but I have no first hand knowledge on that.

pianotuna wrote:
I simply plug the shore power cord into an outlet powered by the inverter.

HUH??

:h

Hi Jamey,

Welcome to the forums.

Often there is a transfer switch, so the 50 amp-shore power cord would not be live.

Mine is old school--I simply plug the shore power cord into an outlet powered by the inverter.