Turn off just inverter

[RLM]

We have an VFXR2812A inverter/charger. My question is whether there is an easy way to turn off just the inverter while on shore power so that the float charging would continue. Shore power runs the 120V loads. But if shore power is interrupted, the inverter will come on. The electrical heaters would quickly run down the battery bank. Turning off the inverter would prevent this.

[fcwlp]

FWIW I have never worked on a solar system on a boat.

Do you have a charge controller? If you do, hopefully you have an AC bypass switch that would power the AC out directly from shore power. This effectively shuts off the inverter and uses the CC to float the batteries.

[raysun]

The inverter charger is being used to maintain Float?

Shore power is connected to the inverter's AC IN?

I don't think there is a way to defeat the inverter's AC OUT in its normal configuration. When shore power is being used, the inverter circuit becomes the charger. When the shore power is dropped, the circuit switches back to inverting.

Perhaps some type of manual transfer switch could be used to bypass the output of the inverter such that shore power is fed to the AC IN of the inverter for its charging function, and rather than from AC OUT, shore power directly to the house loads. If shore power fails, the inverter would switch modes, but its output would see an open circuit until the transfer switch was in the inverter position. Check with a competent marine electrician about the feasibility of such an approach.

A related question. Shore power usually provides a bond between neutral and ground. There should only be one N-G bond in the system. When not on shore power how is N-G bonding done? When on shore power, how is the boat's N-G bond lifted? (Outback makes M series inverters that handle this in the inverter. It is recommended that the N-G connection be made at the power source, in this case the inverter.) Is an isolation transformer used?

[SandyP]

I assume the heaters are only used when on shore power?
If so, then the only solution I can see is to power them via the AC IN line that goes to the inverter.

[Mike Curran]

This isn't an easy way but its doable and it'll work.

Put a single throw, double pole relay in the AC out from your inverter, with the coil energized by shore power. When there is shore power, the contacts will be closed and shore power will continue to feed your loads. When shore power is interrupted, the relay will drop out and your loads will be disconnected from your inverter. You could also use the relay for just your heaters if you wanted your inverter to supply other loads during outages and only disconnect the heaters.

Note if you only have a single phase inverter you only need a single pole relay instead of double pole. Just be sure to size the relay contacts for whatever current your desired interruptible loads draw.

[JeffTaylor]

Do you have a MATE controller/display? My system has two VFX2812 inverter/chargers and a MATE2. Using the MATE, I can turn the inverter off with a press of a button and leave the charger on to float the batteries. I do this often when away from shore power to save the idle current when the inverter is not needed.

(press INV twice, then press the soft key for OFF or SRCH or ON, as needed)

[Mike Curran]

Do you have a MATE controller/display? My system has two VFX2812 inverter/chargers and a MATE2. Using the MATE, I can turn the inverter off with a press of a button and leave the charger on to float the batteries. I do this often when away from shore power to save the idle current when the inverter is not needed.

(press INV twice, then press the soft key for OFF or SRCH or ON, as needed)

Great first post, Jeff

[raysun]

Do you have a MATE controller/display? My system has two VFX2812 inverter/chargers and a MATE2. Using the MATE, I can turn the inverter off with a press of a button and leave the charger on to float the batteries. I do this often when away from shore power to save the idle current when the inverter is not needed.

(press INV twice, then press the soft key for OFF or SRCH or ON, as needed)

In all the time I've employed an FX class inverter, I've never set it OFF, and thought to test whether the charger mode continues to function.

Does it?

[SandyP]

In all the time I've employed an FX class inverter, I've never set it OFF, and thought to test whether the charger mode continues to function.

Does it?

Interested to know this as well.
For the heaters to still work the pass through function would also need to operate with the inverter in OFF mode.

Edit: The only reference I can see to the Inverter On/Off function and its impact on other functions is in the FX/VFX Mobile manual, page 10 :

On/Off Switch
If a system display is not in use, the inverter can be equipped with a switch to turn it on and off.
This switch is not sold as an inverter accessory; a common toggle switch can be used. The switch
is wired to the INVERTER ON/OFF auxiliary terminals. (See the FX and VFX Mobile Series
Inverter/Charger Installation Manual for more information on wiring the switch.)
This switch turns only the inverter on and off. It does not turn the charger or any other function on
or off. All inverter functions will operate according to their programmed settings. Functions
included with a system display will not be available.

[raysun]

In all the time I've employed an FX class inverter, I've never set it OFF, and thought to test whether the charger mode continues to function.

Does it?

Interested to know this as well.
For the heaters to still work the pass through function would also need to operate with the inverter in OFF mode.

Edit: The only reference I can see to the Inverter On/Off function and its impact on other functions is in the FX/VFX Mobile manual, page 10 :

On/Off Switch
If a system display is not in use, the inverter can be equipped with a switch to turn it on and off.
This switch is not sold as an inverter accessory; a common toggle switch can be used. The switch
is wired to the INVERTER ON/OFF auxiliary terminals. (See the FX and VFX Mobile Series
Inverter/Charger Installation Manual for more information on wiring the switch.)
This switch turns only the inverter on and off. It does not turn the charger or any other function on
or off. All inverter functions will operate according to their programmed settings. Functions
included with a system display will not be available.

If the On/Off switch works as the manual implies, then the solution is very simple! A single pole - single throw switch and some small gauge wire does the trick.

[Mike Curran]

Or if there's a Mate in the system, control via Optics.

[jsmith]

Or if there's a Mate in the system, control via Optics.
Screenshot_20201130-203507_Samsung Internet.jpg

That should work as my generator will charge batteries and power loads when the FX3048T is turned off by the original Mate at status/fx/modes/inv control.