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Split phase system able to handle large imbalanced load

Leetbacon

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Oct 17, 2021
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Home backup power setup

Looking for insight on Inverter setup
- Putting together a solar backup system for my house. 240v pony panel with automatic transfer switch.

Option 1
2 - Growatt split phaze inverters
(each inverter has 240v output)
Large 120v loads tend to trip as output is not balanced enough.
I would need an auto transformer on this setup to provide a neutral correct? Also would this solve the load imbalance issue aswell?

2 - Mpp solar lv2424
120v output from each paralleled for 240v

My question is
- If I go with 2 separate 120v inverters this should handle larger potential 120v loads alot better correct? Example: Miter saw
 
Last edited:
Home backup power setup

Looking for insight on Inverter setup
- Putting together a solar backup system for my house. 240v pony panel with automatic transfer switch.

Option 1
2 - Growatt 3k watt split phaze inverters
(each inverter has 240v output)
Large 120v loads tend to trip as output is not balanced enough.
I would need an auto transformer on this setup to provide a neutral correct? Also would this solve the load imbalance issue aswell?

2 - Mpp solar lv2424
120v output from each paralleled for 240v

My question is
- If I go with 2 separate 120v inverters this should handle larger potential 120v loads alot better correct? Example: Miter saw
An Autotransformer will allow almost all of the power to be directed to a single leg.

But if the GroWatts are ‘split-phase’, that implies they already integrate an Autotransformer.

If only L1 and L2 outputs it is not split phase (and no Autotransformer).

If L1, L2, and N outputs, it is split phase and already contains an Autotransformer.

Whether it’s 2 3kW split phase inverters or 2 3kW single-phase inverters + a 6kW Autotransformer, you’ll be able to get close to a full 6kW output on each 120V leg (total of 6kW on both legs).

The LV2424 will deliver a maximum of 2.4kW on each 120V leg. Using 2 in split-phase configuration will deliver a maximum 2.4kW per leg or up to 4.8kW @ 240V power (both legs).
 
An Autotransformer will allow almost all of the power to be directed to a single leg.

But if the GroWatts are ‘split-phase’, that implies they already integrate an Autotransformer.

If only L1 and L2 outputs it is not split phase (and no Autotransformer).

If L1, L2, and N outputs, it is split phase and already contains an Autotransformer.

Whether it’s 2 3kW split phase inverters or 2 3kW single-phase inverters + a 6kW Autotransformer, you’ll be able to get close to a full 6kW output on each 120V leg (total of 6kW on both legs).

The LV2424 will deliver a maximum of 2.4kW on each 120V leg. Using 2 in split-phase configuration will deliver a maximum 2.4kW per leg or up to 4.8kW @ 240V power (both legs).
The SolArk for example is splitphase but will only allow roughly half of its total possible output to each leg
 
An Autotransformer will allow almost all of the power to be directed to a single leg.

But if the GroWatts are ‘split-phase’, that implies they already integrate an Autotransformer.

If only L1 and L2 outputs it is not split phase (and no Autotransformer).

If L1, L2, and N outputs, it is split phase and already contains an Autotransformer.

Whether it’s 2 3kW split phase inverters or 2 3kW single-phase inverters + a 6kW Autotransformer, you’ll be able to get close to a full 6kW output on each 120V leg (total of 6kW on both legs).

The LV2424 will deliver a maximum of 2.4kW on each 120V leg. Using 2 in split-phase configuration will deliver a maximum 2.4kW per leg or up to 4.8kW @ 240V power (both legs).
Great thank you!

The growatts only have L1/L2 ground as outputs
where the Mpp solar's each have L1/N ground.
So it seems I would not need a auto transformer for the Mpps?
 
The SolArk for example is splitphase but will only allow roughly half of its total possible output to each leg
Yes, it depends on the power rating of the Autotransformer.

Half to each leg sounds wrong though - that’s what is available without any Autotransformer at all (just 2 half-power 120V inverters connected out-of-phase).

An Autotransformer rated to half the maximum power of the inverter will allow up to 75% of full power to be delivered to either leg…
 
Yes, it depends on the power rating of the Autotransformer.

Half to each leg sounds wrong though - that’s what is available without any Autotransformer at all (just 2 half-power 120V inverters connected out-of-phase).

An Autotransformer rated to half the maximum power of the inverter will allow up to 75% of full power to be delivered to either leg…
Ok thank you for the information!
 
Great thank you!

The growatts only have L1/L2 ground as outputs
where the Mpp solar's each have L1/N ground.
So it seems I would not need a auto transformer for the Mpps?
No, the MPPs don’t need an Autotransformer (unless you want more than 50% of total power to be available to a single leg).

And the Growatt will need an Autotransformer to deliver 120V power (though that makes me wonder why it is called ‘split phase’

If the Growatt can be configured for 120V output and two can be connected out of phase for split-phase output, then a pair of them is similar to a pair of MPS and can deliver a maximum of 3kW per single leg of 6kW @ 240V (125% the power of a pair of MPPs).

Adding an Autotransformer to either just ‘unlocks’ the capability of delivering close to 100% of max power output to either leg (4.8kW for MPP, 6kW for Growatt).
 
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