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Battery charge energy included or excluded in inverter kW rating?


BritishRacingGreen
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19 hours ago, dropkick said:

Question embedded in title. 

Your title is confusing, because it combines energy and power. But your questions seem to relate to power.

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Let's say solar charges battery. Then can grid  still transfer full 5kw  from AC input to AC output?

It depends on the model, but an Axpert MKS III 5K-48 for example can transfer up to 40 A from AC-in to AC-out. That's about 9 kVA.

The headline 5 kW rating is for battery and/or solar to AC-out, the basic inverting process.

19 hours ago, dropkick said:

In the context of inverter capable of power blending.

When power blending in an MKS III, AC-in is connected to AC-out, so the above applies.

19 hours ago, dropkick said:

Or , another scenario, if no solar , can the inverter charge a battery AND capable of supplying full 5kw load?

When utility charging, some of the 40 A input current limit is diverted to charging the battery. So if charging the battery at say 1.5 kW, there would be some 7.5 kVA left over for the loads.

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6 hours ago, Coulomb said:

Your title is confusing, because it combines energy and power. But your questions seem to relate to power.

It depends on the model, but an Axpert MKS III 5K-48 for example can transfer up to 40 A from AC-in to AC-out. That's about 9 kVA.

The headline 5 kW rating is for battery and/or solar to AC-out, the basic inverting process.

When power blending in an MKS III, AC-in is connected to AC-out, so the above applies.

When utility charging, some of the 40 A input current limit is diverted to charging the battery. So if charging the battery at say 1.5 kW, there would be some 7.5 kVA left over for the loads.

Thank you for valuable info, coulomb ...... Again! Yes my relation between energy and power misleading, sorry.

 

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@Coulomb

 

I think the product manufacturers should provide some half decent functional schematic block diagrams of their inverters transfer functions. That includes most types, not limited to voltronic.  Specifications are also only bare minimum. 

While I perfectly understand that the machines are consumer grade ,  the functionality of modern inverter is not trivial.  Fortunately , in this regards, we have forums and enthusiasts  like you. Cheers.

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22 hours ago, dropkick said:

I think the product manufacturers should provide some half decent functional schematic block diagrams

A full schematic would be great. I can show my block diagram though:

 

1412733072_Presumedblockdiagram.png.470bb6e03c0e118e86e70d76efbc9df5.png

For the Axpert MKS II/III (and Axpert VM II/III), ignore the blue and red parts of the above. In SUB mode, both switches would be on, and the three converters at the right would have power flow right to left, in order to charge the battery.

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  • 2 weeks later...
On 2021/08/25 at 4:33 PM, Coulomb said:

A full schematic would be great. I can show my block diagram though:

 

1412733072_Presumedblockdiagram.png.470bb6e03c0e118e86e70d76efbc9df5.png

For the Axpert MKS II/III (and Axpert VM II/III), ignore the blue and red parts of the above. In SUB mode, both switches would be on, and the three converters at the right would have power flow right to left, in order to charge the battery.

@CoulombColoumb thank it has been a while since you have posted this schematic, and I wanted to study a few things first , before inundating you with silly questions.

Ok the kings AC/DC block I presume is to reconstruct input AC , because king is advertised as compatible with bad rural areas where AC is not always in spec.is that right?

So for my mks3 or VMIII I forget about the red block.

So the schematic infers a DC coupled hybrid , where batt and solar are entertained as such.

But I also know to my inverter blends, so I assume that blending of AC input and inverter output(DC/AC) is done in AC coupled domain at the output. Is that right?

The  block that confuses me is the bidirectional arrow attached to the DC/AC converter. What does that imply?

Kind regards there down under.

 

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49 minutes ago, dropkick said:

Ok the kings AC/DC block I presume is to reconstruct input AC , because king is advertised as compatible with bad rural areas where AC is not always in spec.is that right?

We're perhaps having minor translation problems here. The King's AC-DC block rectifies the input AC (in a manner that presents a very nearly unity power factor to the mains), yes. Rectification is just a term for converting AC to DC. The primary reason for doing this however is for the "zero transfer" time. The load can switch from being battery powered to being utility powered instantly; there is no waiting for relays to pull in.

However, if the output is overloaded (more than 5 kW load for a 5 kW model), it does have to switch to bypass mode, like all the other models, incurring the usual 10 or 20 ms delay (depending on whether the AC input range is set to UPS or APL respectively.

49 minutes ago, dropkick said:

So for my mks3 or VMIII I forget about the red block.

Yes.

49 minutes ago, dropkick said:

So the schematic infers a DC coupled hybrid , where batt and solar are entertained as such.

Battery and solar power are combined  / blended at the DC bus, yes.

49 minutes ago, dropkick said:

But I also know to my inverter blends, so I assume that blending of AC input and inverter output(DC/AC) is done in AC coupled domain at the output. Is that right?

Yes. The DC-AC converter (the actual inverter) is synchronised with the AC input, so that power can be pushed or pulled from the AC (input and output, which are connected together in SUB mode where blending happens).

49 minutes ago, dropkick said:

The  block that confuses me is the bidirectional arrow attached to the DC/AC converter. What does that imply?

 

40 minutes ago, dropkick said:

Ok you have stated that the AC input must charge the batt also, that's why it's bidirectional, I suppose.

Yes. When utility charging, the power flow is back towards the battery via the DC-DC converter, which is also bidirectional. 

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