LV 6048 hybrid with GRID bypass relay/contactor. Is it practical?

[LasseH]

Looking for some advice designing a Grid to inverter bypass system.

I hope someone here has a similar setup, as I am looking for a cheap setup of:
- 1000$ solar panels, 1000$ inverter, 1000$ DIY battery with a project cost no more than 4000$.

Goal:
- 2 or 3 phase bypass relay (don't know if neutral is necessary) switches between my inverter and the grid.
- Inverter feeds main breaker panel when amps used are less than 25A (6kW inverter)
- Grid feeds the main breaker panel when battery is low (less than 20%) or amps are higher than 25A
- A shunt will monitor and control the bypass relay based on amp readings.
- Modbus will be used to collect the data from battery and inverter to actuate control relays for the bypass.

Questions:
- Is this applicable to preventing inverter faults and keeping the system running continuous?
- Anyone of you guys have a similar setup?
- Is 2 phase or 3 phase bypass relays used?
- Anyone has a suggestion to a relay with fast contactor motion?
- Any suggestions on shunts that has fast detection with programmable relay outputs to pull this off?
- Is there programmable shunts with built in contactor bypass, or do you have to get 2 sepererate devices?

 

[BentleyJ]

The requirement for a high relay speed that can deliver virtually continuous power is going to be the issue. Since a low cost inverter cannot sync with grid power you must use an open transition switch. A closed transition transfer switch cannot be used as there is a momentary time period where both sources are connected but they will be out of phase.

 

[LasseH]

The requirement for a high relay speed that can deliver virtually continuous power is going to be the issue. Since a low cost inverter cannot sync with grid power you must use an open transition switch. A closed transition transfer switch cannot be used as there is a momentary time period where both sources are connected but they will be out of phase.

If the LV 6048 hybrid has an input connecting it to the grid. Does this mean that the inverter has the ability to perform a closed transition?

Looked up some automatic transfer switches, it appear that they sell a lot of them in the range of 100-250A around 100-200$.

Would something like this be able to handle it?





I'm assuming that most Automatic Transfer Switches (ATS) deal with a small period of power break between the transition:



I just wanna use the grid for high power surges and use a transfer switch to go back and forth between my inverter and the grid...

It would be even better if the transfer switch had a built in shunt to measure the current as well for some programmability.

Thanks for your feedback!

 

[Kingfish24]

The LV6048 does what you want automatically, when the output power exceeds 6k in a single phase
(120v setup)or 3k on one leg of split phase (120v/120v) it trips to grid power and then resets to inverter/battery after a preset period or after the load is reduced. You can also set it to switch to grid power at a specific battery charge level at a certain time of day that you predesignate if you monitor it with the Solar Assistant app.

 

[Kingfish24]

Using Solar Assistant you can remotely switch between grid and battery anytime you like also as well as adjust inverter settings such as max allowed grid charging current. On a cloudy day if my batteries dont fully charge and I know tomorrow will be cloudy also, I switch to grid after 9pm when the rates are lowest (time of use meter) and charge my batteries overnight.

 

[1201]

Using Solar Assistant you can remotely switch between grid and battery anytime you like also as well as adjust inverter settings such as max allowed grid charging current. On a cloudy day if my batteries dont fully charge and I know tomorrow will be cloudy also, I switch to grid after 9pm when the rates are lowest (time of use meter) and charge my batteries overnight.

Once you switch to grid does it still use any battery power?