2 separate battery banks/inverters feeding into 1x AC board (off grid) ?

[gramos100]

New 48v system off grid . we have 4x 100 amp li batteries on one inverter , also 2x 100 amp li batteries on another inverter.
Can both be connected to one AC board to house supply ?
Right now they have no BMS comms between them and are fed ,,full by solar .
The 4 batt system is connected to the AC board and is supplying power to house .
We want to add the 2 batt sytem output to the same AC board .

 

[Mattb4]

Your inverters can not be connected together for AC output unless they are designed to stack or parallel which is not possible based on you having 24vDC inverter and 48vDC inverters. Nor can the 24vDC setup be connected to the 48vDC setup.

You can power separate loads but that is it.

Stacking (series in DC) or paralleling voltage supplies require that they meet certain parameters. If they don't match properly current flow between the mismatched outputs will cause damage.

 

[BarracudaBob]

I had thought of this with a older SLA battery pack and new LPF. It would have been cool to run two inverters in parallel so I could use what I had. Every answer I received that they must be on the same battery bank.

I got rid of all my lead.. They were faithful for so many years but they had to go.

 

[timselectric]

I had thought of this with a older SLA battery pack and new LPF. It would have been cool to run two inverters in parallel so I could use what I had. Every answer I received that they must be on the same battery bank.

I got rid of all my lead.. They were faithful for so many years but they had to go.

A few of us are running LA and LFP in the same bank.
It works just fine. The LA just acts as a backup to the LFP, because it doesn't kick in until the voltage starts dropping.

 

[gramos100]

Your inverters can not be connected together for AC output unless they are designed to stack or parallel which is not possible based on you having 24vDC inverter and 48vDC inverters. Nor can the 24vDC setup be connected to the 48vDC setup.

You can power separate loads but that is it.

Stacking (series in DC) or paralleling voltage supplies require that they meet certain parameters. If they don't match properly current flow between the mismatched outputs will cause damage.

All batteries are lithium 48v , not 24v

 

[wpns]

New 48v system off grid . we have 4x 100 amp li batteries on one inverter , also 2x 100 amp li batteries on another inverter.
Can both be connected to one AC board to house supply ?
Right now they have no BMS comms between them and are fed ,,full by solar .
The 4 batt system is connected to the AC board and is supplying power to house .
We want to add the 2 batt sytem output to the same AC board .

What are the mfr and model of each of your inverters? If they are the same, then maybe. If they are different then no.

 

[crossy]

Yeah ^^^. We need to know exactly what you have.

There may be solutions but without that detail everyone is in the dark.

 

[Mattb4]

All batteries are lithium 48v , not 24v

My mistake. Your description of 4 Litime on one inverter and 2 on the other was the reason. A lot of folks series connect 12v batteries.

My answer however is the same. If your inverters are not designed to work together you can not use them to supply AC out to the same load panel.

 

[crossy]

This ^^^.

You can however, connect the two "48V" packs in parallel to make one big pack so your total solar energy is pooled together for either inverter to use.

If you tell us which inverters you have there may be solutions to run in parallel on the AC side.

 

[740GLE]

All batteries are lithium 48v , not 24v

Any reason why you’d want to keep these banks seporate?

Typically when inverters are running in parallel feeding a single AC source they’d like the same DC bus, so you’d be needing to combine all batteries on one bus bar.

 

[gramos100]

Yeah ^^^. We need to know exactly what you have.

There may be solutions but without that detail everyone is in the dark.

4x Northbatt 48v, 100a batteries on 1x Victron 8kw inverter
2x Rosen 48v, 100a batteries on 1x Rosen 6kw inverter
on separate circuits .
My question is can the two inverter AC outputs be connected together in 1 x230v main board feeding the house ?

 

[gramos100]

"Any reason why you’d want to keep these banks seporate? "

Yes , the 4 batteries are 6+ months older and 16s
The 2x batteries are new and 15s so they have to use different inverters/BMS

 

[wpns]

4x Northbatt 48v, 100a batteries on 1x Victron 8kw inverter
2x Rosen 48v, 100a batteries on 1x Rosen 6kw inverter
on separate circuits .
My question is can the two inverter AC outputs be connected together in 1 x230v main board feeding the house ?

Unless the inverters are designed to be paralleled with each other then no.
Their frequencies will not be locked, so sometime there’ll be zero volts between them and sometimes there will be 240V between them.

 

[wpns]

"Any reason why you’d want to keep these banks seporate? "

Yes , the 4 batteries are 6+ months older and 16s
The 2x batteries are new and 15s so they have to use different inverters/BMS

Then no again, you can’t mix 15s and 16s, but you seem to know that.

Battery age doesn’t matter, especially at 6 months delta.

 

[gramos100]

This ^^^.

You can however, connect the two "48V" packs in parallel to make one big pack so your total solar energy is pooled together for either inverter to use.

If you tell us which inverters you have there may be solutions to run in parallel on the AC side.

Neither inverter (Rosen/ Victron) has the capacity for all the batteries to be paralleled , so they are separated

 

[Mattb4]

4x Northbatt 48v, 100a batteries on 1x Victron 8kw inverter
2x Rosen 48v, 100a batteries on 1x Rosen 6kw inverter
on separate circuits .
My question is can the two inverter AC outputs be connected together in 1 x230v main board feeding the house ?

No. Separate derived AC supplies will not have their sine waves in synch to allow parallel operation. AC, or alternating current, is a sine wave where voltage goes from a negative to a positive value so many times a second (hz).

 

[gramos100]

No. Separate derived AC supplies will not have their sine waves in synch to allow parallel operation. AC, or alternating current, is a sine wave where voltage goes from a negative to a positive value so many times a second (hz).

Thank you , best reply yet , I understand that . Is there a way to sync the 2 AC currents ?

 

[Khabra]

New 48v system off grid . we have 4x 100 amp li batteries on one inverter , also 2x 100 amp li batteries on another inverter.
Can both be connected to one AC board to house supply ?
Right now they have no BMS comms between them and are fed ,,full by solar .
The 4 batt system is connected to the AC board and is supplying power to house .
We want to add the 2 batt sytem output to the same AC board .

Having a separate load center to feed low wattage loads like lighting on small system having small battery bank. Using 48V 400 AH for heavy loads makes more sense. I have one split phase 120V/240V connected to one panel and single pahse inverter connected to lightings loads only. I use small inverter 120V for lighting and split phase for Washer, Dryer , Fridge, Microwave etc.

 

[wpns]

Thank you , best reply yet , I understand that . Is there a way to sync the 2 AC currents ?

Not unless they are designed for it, which always means the same manufacturer and usually means the same model.

 

[gramos100]

Righto , thats clearer now, thanks everyone . I ll split the loads to each inverter , no sine wave issues then .