Growatt LVM-3000 24P here. Can I connect AC IN and AC OUT to same outlet?

helloterran

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Feb 28, 2022
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It's a RV build. The context is, RV systems are designed to alternate between 2 AC sources: the default mode is for the shore power to feed every 110v load, and when the generator is turned on, an actuator gets activated after ~30s delay and switch the entire vehicle's 110v circuit to the generator side, until the generator stops. There's no builtin inverter in my RV.

What I've done is basically adding a "suicide cable" to the shore power terminals in the distributor box, so I'm essentially connect the RV 110v circuit to whatever inverter that's generating 110v power. I was using a Bluetti EB240 power station before switching to all-in-one systems, so when the powerstation inverter is on, the vehicle runs as if it's hooked up to shore power 24/7, even on the road.

There're 2 downsides fom this design. 1: I cannot connect to shore power before I manually "unplug" the power station from the RV otherwise shore power will fry powerstation's inverter in a split of a second. Since I'm almost entirely boondocking I never had to connect to shore power last year, so this wasn't a big problem for me. 2: everytime I turn on the generator to charge the power station I have to plugin the charging cable to the RV, and unplug the charging cable after it's done, since otherwise it will only draw from its own output, and burn battery juice through the converter/inverter loss.

Now with Growatt, which comes with separate AC IN and AC OUT ports, I'm wondering what happens if I connect both AC IN / AC OUT to my RV's 110V circuit, and turn on the Growatt inverter: what will happen? It probably won't fry anything, but my goal is to NOT having to worry about plugging / unplugging AC IN from RV no matter what the power source.

Will the Growatt recognize the 110v as "it's own output" and refrain from drawing power from it? Is there a system that can do this?
 
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Sounds like you've pulled the pin on the grenade and are getting ready to throw it... or drop it at your feet.

Sounds like your standard setup:

Shore/Generator on input to automatic transfer switch (ATS). Output of ATS to AC panel or:

Shore/generator -----------> ATS -----------> AC panel

Should be:

Shore/generator -----------> ATS -----------> Inverter -----------> AC panel

That way when you plug into shore or run the generator, it passes the output to the input of the growatt. The growatt passes the input through to the loads and uses surplus to charge the batteries.
 
Well, it's an RV electric system so I can't simply insert an ATS between shore/generator and AC panel w/o re-do dozens of high-amp wires through the cabinet walls and insulation layers. I'm eager to know if there're drop-in solutions that can fulfill my needs.
 
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