MPP LVX6048WP questions

[k490]

I'm looking for an inverter that will combine AC input and solar/battery to reduce my electric bill without going to a grid tied inverter. After doing some research I found some post here about an EG4-6000EX back-feeding the grid, and a video of someone claiming their MPP LVX6048WP is back-feeding the grid with 250 watts when it was set to off-grid mode. I also read here that the LVX6048WP had an issue where the generator input was energized which is should not be. I'm trying to find a UL listed inverter for no more than $1500 maybe it's not possible. I can't afford to get into trouble with my utility back-feeding. I don't even know how you can test for that before you plug it in. I suppose have to look for voltage on the grid input side before connecting it while it's in off-grid mode.

Does this seem to be a problem with some hybrid inverters just by design is the grid input directly connected to the inverter output combining the two? When you set a hybrid to off grid only it's really just using internal CT clamps to keep it from back-feeding.

Video I found on YT poster says LVX6048WP is back-feeding his meter is going backwards with the inverter set to off-grid.

 

[sunshine_eggo]

This has been an issue with certain Voltronic-type inverter models (older EG4, Growatt, MPP Solar, etc.).

With few exceptions, it does appear to be almost exclusively with hybrid type inverters that are capable of backfeed.

 

[k490]

This has been an issue with certain Voltronic-type inverter models (older EG4, Growatt, MPP Solar, etc.).

With few exceptions, it does appear to be almost exclusively with hybrid type inverters that are capable of backfeed.

The MPP is a Voltroic that makes sense now. I don't understand why someone can't make an off-grid AIO that will charge the battery with the grid at the same time the PV charger is also charging the battery. The inverter is powering the load off the battery. I have that now with my separate charge controller, and 1500-watt inverter. I have a lithium battery charger plugged into the grid.

 

[sunshine_eggo]

The MPP is a Voltroic that makes sense now. I don't understand why someone can't make an off-grid AIO that will charge the battery with the grid at the same time the PV charger is also charging the battery.

Ummm...that's a very common feature. Many can both charge the battery from both grid and PV.

The inverter is powering the load off the battery.

THIS is where it breaks down. You can't invert and AC charge at the same time. It's basically the same circuitry that inverts DC to AC that converts AC to DC. When on grid, it must pass through grid to loads. This is how all inverter/chargers work.

This is not AiO specific. Tier-1 inverter/chargers like Schneider, Victron, Magnum, Outback, etc., work this way.

I have that now with my separate charge controller, and 1500-watt inverter. I have a lithium battery charger plugged into the grid.

You have a standalone inverter. AiO units are inverter/chargers. They behave differently.

Many choose the 48V Chargeverter to achieve your configuration. Additionally, the Voltronics units are very intolerant of non-inverter generator power. They will refuse to charge from generator unless set to a very low charge rate. This is the primary reason a Chargeverter exists.

 

[k490]

I'll probably just buy the EG4-6000xp figure it out best way to use it. I don't want to run the risk of back feeding illegally. When I called EG4 support they said if I waited, they were going to release a new inverter I would be upset that I didn't wait. Who knows how long it will be I really want to get my system running this summer.

 

[Gib]

I have 2 MPP LV6048WP inverters running in parallel. I am also concerned about backfeeding the grid.
The inverters are set for Offgrid 1 operation and the setting for - Allow to feed-in to the grid - is unchecked.
I have a 40 amp grid tied breaker feeding each of the inverters for backup.

Spot checking for back feed is easily done with an AC voltmeter.
With the grid supply breakers feeding the inverters turned off. Measure the AC voltage at the 240 vac breaker output or at the inverter 240 vac inlet.
My measurements show 0 vac, so I know there is no feedback.

One note of caution on measuring AC voltage on open circuit wires that have no load on them. Sometimes you can pick up induced AC voltage readings. To eliminate the chance of induced voltage causing false readings you can connect a device with the correct voltage rating across the open circuit. Such as a power resistor or 120/240 volt heater. Induced voltage will disappear from your readings and any current reading should be milliamps or lower.

 

[Sanwizard]

I have 2 MPP LV6048WP inverters running in parallel. I am also concerned about backfeeding the grid.
The inverters are set for Offgrid 1 operation and the setting for - Allow to feed-in to the grid - is unchecked.
I have a 40 amp grid tied breaker feeding each of the inverters for backup.

Spot checking for back feed is easily done with an AC voltmeter.
With the grid supply breakers feeding the inverters turned off. Measure the AC voltage at the 240 vac breaker output or at the inverter 240 vac inlet.
My measurements show 0 vac, so I know there is no feedback.

One note of caution on measuring AC voltage on open circuit wires that have no load on them. Sometimes you can pick up induced AC voltage readings. To eliminate the chance of induced voltage causing false readings you can connect a device with the correct voltage rating across the open circuit. Such as a power resistor or 120/240 volt heater. Induced voltage will disappear from your readings and any current reading should be milliamps or lower.

I just noticed that the LVX6048WP's seem to need 1KW to support around a half KW of load. Anyone else notice this? Or is Solar Assistant giving me wrong data...

 

[Gib]

I don't use Solar Assistant. Are you feeding the grid? The numbers would make more sense if that's what is going on. I haven't seen big losses going from battery to load.

 

[Sanwizard]

I don't use Solar Assistant. Are you feeding the grid? The numbers would make more sense if that's what is going on. I haven't seen big losses going from battery to load.

Nope. Off-grid mode 3. Seems to be a DC to AC conversion efficiency issue. I guess we get what we pay for.