Behaviors when connecting single phase to split phase inverter

[theoloong]

Hi,

Long story short, I'm designing a solar system for RV and I'd like to run a split phase panel for all my appliances a splifphase solar inverter charger. However, I don't get splitphase anywhere. For most of the time I get 120v 30A or 120v 15A (household outlet).

My questiosn is, what will be the behavior, or is it even possible to supply a single phase AC power to a splitPhase inverter and charge the battery?

If the answer to my first question is NO, the alternative setup I'm thinking is to have a dedicated 120v inverter charger just for charging the battery with 120v, and the splitphase interver charger will just sip power from the battery. Will this work?

Thanks

 

[BentleyJ]

There are so many inverter products available I'm not sure if any of the All In One split phase inverters can accept 120V input while outputting 240V.
What you suggest would be an excellent "work around". Instead of the All In One type Inverter/SCC/AC Charger simply get a quality stand alone inverter and then to charge the batteries there are products available that have both the Solar Charge Controller and a plug in AC Charger built in.

 

[acdoctor]

My personal experience is on a 50 amp 240 volt split phase shore power cord you are receiving 240 volts split phase to the main breaker in the coach. If you connect the same coach to a 30 amp single phase shore power through a adapter inside the adapter it splits the single phase 120 volt into two single phase 120 volt wires of the same phase. The way this is able to work is there is no 240 split phase circuits or appliances in the coach. In the breaker panel with all 120 volt single phase circuits they don’t have to be opposing phases so long as they are all receiving 120 volts and neutral.

 

[theoloong]

My personal experience is on a 50 amp 240 volt split phase shore power cord you are receiving 240 volts split phase to the main breaker in the coach. If you connect the same coach to a 30 amp single phase shore power through a adapter inside the adapter it splits the single phase 120 volt into two single phase 120 volt wires of the same phase. The way this is able to work is there is no 240 split phase circuits or appliances in the coach. In the breaker panel with all 120 volt single phase circuits they don’t have to be opposing phases so long as they are all receiving 120 volts and neutral.

Yes, this is the scenario I'm talking about. The single phase 30A is feeding into both L1 and L2. All 120v appliances will work fine. This makes the L1 == L2 and no 240v. And I wonder if the all in one splitphase charger inverter will be able to config itself from splitphase back to single phase base on the input.

 

[acdoctor]

I suppose my question would be why would you need the 240 split when all you really need is 50 amp 120 single?

 

[theoloong]

I suppose my question would be why would you need the 240 split when all you really need is 50 amp 120 single?

Not because I need 240v, but for using all 50A@240v to charge the battery.

 

[Horsefly]

My personal experience is on a 50 amp 240 volt split phase shore power cord you are receiving 240 volts split phase to the main breaker in the coach. If you connect the same coach to a 30 amp single phase shore power through a adapter inside the adapter it splits the single phase 120 volt into two single phase 120 volt wires of the same phase. The way this is able to work is there is no 240 split phase circuits or appliances in the coach. In the breaker panel with all 120 volt single phase circuits they don’t have to be opposing phases so long as they are all receiving 120 volts and neutral.

Wow - That's a little surprising that they would put the same input on both sides of what is supposed to appear as a split phase feed. Doesn't seem good.

For what it is worth, my Schneider SW4024 inverter/charger can take in single phase 120VAC on L1 of the inputs, and put out 240VAC split phase on the outputs. I've not tried it (my input is 240VAC split phase from a generator), but that's what the manual says it can do.

 

[theoloong]

Wow - That's a little surprising that they would put the same input on both sides of what is supposed to appear as a split phase feed. Doesn't seem good.

For what it is worth, my Schneider SW4024 inverter/charger can take in single phase 120VAC on L1 of the inputs, and put out 240VAC split phase on the outputs. I've not tried it (my input is 240VAC split phase from a generator), but that's what the manual says it can do.

The reason RV feed single phase into both phase when you only get 120v is that the panel load will still be balanced, except you don't get 240v.

So you're saying when you only have sinlge phase, you feed it into L1 and leave L2 floating. Everything works fine in terms of charging battery, and outputing split phase? I wonder if this imbalance AC hookup will effect performance, such as charging battery or utility passthrough.

 

[Horsefly]

So you're saying when you only have sinlge phase, you feed it into L1 and leave L2 floating. Everything works fine in terms of charging battery, and outputing split phase? I wonder if this imbalance AC hookup will effect performance, such as charging battery or utility passthrough.

Like I said, I haven't tried it, but the manual says it works. L1 has 120V relative to ground, and L2 is floating, and you get split phase 240V out. It only works with L1. If you leave L1 floating and put 120V on L2, you get nothing out. I'm sure the charger works with the L1 power.

Not sure what you mean about how it will affect utility passthrough.

 

[theoloong]

Like I said, I haven't tried it, but the manual says it works. L1 has 120V relative to ground, and L2 is floating, and you get split phase 240V out. It only works with L1. If you leave L1 floating and put 120V on L2, you get nothing out. I'm sure the charger works with the L1 power.

Not sure what you mean about how it will affect utility passthrough.

Thanks for clarifying. Is there a name/scenario that the manual is using to describe this situation (single phase input split phase output)?

Regarding utility passthrough, I mean bypass/relay. For example, say I'm loading both phase with 2000w, so 4000w in total. If the battery is fully charged, the inverter should be in bypass mode -- not using the battery at all. Say I only have L1 connected, we will have a unbalanced input (L1 connected, L2 floating), with balanced load (L1 2000W L2 2000W). Will L1 take 4000w and redistribute it into both phase, or only 2000w and supply the other phase with battery power.