Just thinking - two different inverters sharing a battery bank

[SparkyJJO]

This is just me thinking, not trying this (yet?)

If I get the homestead I'm hoping for eventually, my 8kW Radian would easily handle a good amount of stuff, nasty surge loads, etc. Thing is, 8kW might not cover everything. Ideally, I think I'd parallel two of them. But, they may not ever make more so that may not be possible. Sad times.

So I got to thinking - maybe I would put the Radian doing heavy stuff (well pump, AC, the welder socket, etc), and get another inverter for regular stuff (let's just say an 18kpv for giggles). Would they have to have isolated battery banks, or could they share a single large battery bank? No comms likely.

 

[Zapper77]

This is just me thinking, not trying this (yet?)

If I get the homestead I'm hoping for eventually, my 8kW Radian would easily handle a good amount of stuff, nasty surge loads, etc. Thing is, 8kW might not cover everything. Ideally, I think I'd parallel two of them. But, they may not ever make more so that may not be possible. Sad times.

So I got to thinking - maybe I would put the Radian doing heavy stuff (well pump, AC, the welder socket, etc), and get another inverter for regular stuff (let's just say an 18kpv for giggles). Would they have to have isolated battery banks, or could they share a single large battery bank? No comms likely.

Does the radian allow grid sell back?

 

[teal95]

Yes, doing it now. Started with SolArk with comms hooked up on the batteries. Have now added 6500ex to make 3 phase. I don't have their AC wired up but I do have a string of panels going into it. Running those on voltage mode.

 

[ShaneC]

Both pulling power from the batteries at the same time would be fine assuming the batteries can provide the required discharge current, large enough cables are used and fused. I'm not sure if the Radian supports charging from mains. I imagine the only issue you'd have is is both charging at the same time. You'd need to make sure their charging configuration was identical.

 

[sollap]

It'll work fine in voltage mode without battery comms. Just keep in mind that anything measured by the inverters (SOC, remaining run time, etc) will always be wrong. You'll need to put a high quality shunt (and a way to read it) between the battery bank and the inverters to get that information.

 

[timselectric]

This is just me thinking, not trying this (yet?)

If I get the homestead I'm hoping for eventually, my 8kW Radian would easily handle a good amount of stuff, nasty surge loads, etc. Thing is, 8kW might not cover everything. Ideally, I think I'd parallel two of them. But, they may not ever make more so that may not be possible. Sad times.

So I got to thinking - maybe I would put the Radian doing heavy stuff (well pump, AC, the welder socket, etc), and get another inverter for regular stuff (let's just say an 18kpv for giggles). Would they have to have isolated battery banks, or could they share a single large battery bank? No comms likely.

Sharing the same battery bank is perfectly fine.

 

[SparkyJJO]

Does the radian allow grid sell back?

Yes but I don't plan on doing that if/when I get the homestead.

Both pulling power from the batteries at the same time would be fine assuming the batteries can provide the required discharge current, large enough cables are used and fused. I'm not sure if the Radian supports charging from mains. I imagine the only issue you'd have is is both charging at the same time. You'd need to make sure their charging configuration was identical.

Radian can charge from the mains, but that wouldn't be my normal usage. The idea is the SCCs would charge and the Radian would be only inverting 99.9999% of the time.

It'll work fine in voltage mode without battery comms. Just keep in mind that anything measured by the inverters (SOC, remaining run time, etc) will always be wrong. You'll need to put a high quality shunt (and a way to read it) between the battery bank and the inverters to get that information.

This is what I thought, but just was looking for a sanity check.

Thanks everyone

 

[Johneb]

Yes but I don't plan on doing that if/when I get the homestead.


Radian can charge from the mains, but that wouldn't be my normal usage. The idea is the SCCs would charge and the Radian would be only inverting 99.9999% of the time.


This is what I thought, but just was looking for a sanity check.

Thanks everyone

I have the radiant 8048A with three FM 80 SC’s. You can actually do four FM 80s on that for 16 kW total. Let the radian affirm do your charging and your inverters can run off of both battery runoff the same battery bank

 

[OffGridInTheCity]

I run 2 x 12,000w inverters (24,000w total) from the same battery bank. What I do is run each one to it's own AC distribution panel (to power separate circuits) but.... cross connect the distribution panels so each panel can power the other - e.g. 1 inverter can power all circuits.

This let's me choose 1 or the other inverter (for backup in case one goes bad) and to do only 12,000w in winter (less PV / less inverter idle power loss) and 24,000w in summer (excess PV). There's a little bit of manual circuit breaker toggling and I have to be careful to not cross-connect both live inverters - but it's manageable with good labels and just a cup of coffee for a clear head.

Here's a pic

 

[timselectric]

I run 2 x 12,000w inverters (24,000w total) from the same battery bank. What I do is run each one to it's own AC distribution panel (to power separate circuits) but.... cross connect the distribution panels so each panel can power the other - e.g. 1 inverter can power all circuits.

This let's me choose 1 or the other inverter (for backup in case one goes bad) and to do only 12,000w in winter (less PV / less inverter idle power loss) and 24,000w in summer (excess PV). There's a little bit of manual circuit breaker toggling and I have to be careful to not cross-connect both live inverters - but it's manageable with good labels and just a cup of coffee for a clear head.

Here's a pic
View attachment 297004

Breaker interlocks protect you from yourself, on those hazy days.

 

[OffGridInTheCity]

Breaker interlocks protect you from yourself, on those hazy days.

Over time and after the expense of replacing an inverter that died at 25,000hrs, I've gotten lazy and just run 1 inverter. This costs me ~7% less consumption per year that I could do... but means that I only switch when an inverter dies. Maybe once every 5 yrs?

 

[marionw]

I run 2 x 12,000w inverters (24,000w total) from the same battery bank. What I do is run each one to it's own AC distribution panel (to power separate circuits) but.... cross connect the distribution panels so each panel can power the other - e.g. 1 inverter can power all circuits.

This let's me choose 1 or the other inverter (for backup in case one goes bad) and to do only 12,000w in winter (less PV / less inverter idle power loss) and 24,000w in summer (excess PV). There's a little bit of manual circuit breaker toggling and I have to be careful to not cross-connect both live inverters - but it's manageable with good labels and just a cup of coffee for a clear head.

Here's a pic
View attachment 297004

If the cross connect break is mounted next to the Inverter breaker you could install a metal rocker interlock which would prevent both breakers from being closed at the same time.