Inverter Question

[Kloon]

19 hours ago, jdp said:

Yes that is what a GTI does. It makes power all the time, Extra goes to the grid. If you need more it will pull the more from the grid.

I get that, but that still does not answer the question if you can have the inverter next to the grid and have the grid still supplement your excess energy needs. What I mean by next to the grid is, not having the grid being fed through the inverter, but I guess then there will be no way of telling how much extra energy is needed to draw from the grid.

[superdiy]

On 5/4/2016 at 8:52 AM, jdp said:

So if this is the case why do I get a overload warning when I go over 5Kw if the inverter can handle more ? and by more I mean constant draw not just spikes.

I beeps all the time and the fans come on. I don't think it will last if I run 8kw on 5kw all the time.

You do get the overload warning, because if the grid fails at that time the inverter will also shut down - it is still a warning - not a "fault" or "issue".  you can switch off the buzzer if it bothers you.  I also don't recommend it for extended periods at a time, as I've mentioned before, but for a few minutes at a time, it should be fine.

On 5/4/2016 at 9:02 AM, jdp said:

When I say " The rating is the total. You can not run 8kw on a 5kw unit. " I am talking about the normal operating Kw, not the now and then. If the it was not the case then why do we have ratings, then we would just have a inverter and not have to worry about sizing etc.

The infinis can do this "overloading" thing while the grid is available, so can the Imeon 3.6 (and maybe other Imeon inverters), but most other inverters cannot do this. As you know, the very popular Axpert inverters cannot handle overloads for more than a few seconds - it simply switches off.

[Guest]

Ok so then what you are saying is that the rating 5kw is what the inverter can handle when on battery power. On grid it can handle more but it is just for short times not jusk spikes. 

[Guest]

38 minutes ago, Kloon said:

I get that, but that still does not answer the question if you can have the inverter next to the grid and have the grid still supplement your excess energy needs. What I mean by next to the grid is, not having the grid being fed through the inverter, but I guess then there will be no way of telling how much extra energy is needed to draw from the grid.

Kloon here we spoke about this thopic

 

[superdiy]

32 minutes ago, Kloon said:

@Janma Thanks, actually looking to do that. I did some research and seems like the efergy is a good start, but will read up some more and perhaps start another topic on that.

Just keep in mind - the efergy meter measures apparent power, not real power. Your utility energy meter measures real power and you only pay for real power consumption. The efergy does not take the power factor into account, so for a pure resistive load like a kettle, geyser or incandescent bulb it is fine, but if you measure any inductive or capacitive load like fridges, microwave ovens, computers, TV's, DSTV etc. etc. the reading will be the apparent power and depending on the power factor of the item being measured, it might differ quite a lot.

As an example, I've measured the standby power of an old LCD TV, apparent power was 18W and actual power was 3W.

But to confuse you even more, when you convert DC to AC (inverter running on battery or PV) it will consume the same amount of power on the DC side as the measured AC apparent power, so in the example above, keeping that TV on standby via an inverter will draw 18W from the battery or PV panels (losses and efficiency excluded).

[superdiy]

9 minutes ago, jdp said:

Ok so then what you are saying is that the rating 5kw is what the inverter can handle when on battery power. On grid it can handle more but it is just for short times not jusk spikes. 

Yes, that is the beauty about the product. Being a hybrid, it combines power sources to supply the load, depending on the configuration, it can combine PV and/or battery and/or the grid to supply the load. Let's take the 3K infini as example - when the grid is not available the inverter will combine PV and/or battery to supply a load of up to 3KW, but if the grid is available, that 3KW limitation is not applicable anymore, because the inverter will use PV and/or battery and invert up to 3KW and then combine the grid with that 3KW to supply a load of much more than 3KW.

[Guest]

Superdiy, can these units be set to power all from solar, pick up difference from Eskom if solar is short and only use batteries if there is no Eskom?

[Guest]

TTT Yes that is the way the Infini works.

[Kloon]

So that answers my question then. If I run a 3KW unit in grid-tie mode and need to use 6KW total for say an hour at a time it should be fine as long as Eskom is online to supply the shortfall? I get that as soon as the grid goes down so will the whole unit seeing as I don't want to run batteries as a start. And this all can then happen with the DB connected to the inverter, perhaps just add a changeover switch to bypass the inverter and use Eskom directly should the need arise.

[Guest]

Kloon let me put it this way. You can run it in 2 ways.

1) You run the loads through the inverter. The following applies.

    a)) If you have batteries and eskom falls away the load will be carried by the batteries like a UPS.

    b)) You have have a max rating of 3Kw, 6Kw for short periods and spikes.

 

2) Bypass the Inverter and have it sit on the eskom line where you draw the power. The following applies.

  a)) If you have batteries and eskom falls away you will have a power failure until you switch back to carry the load off the inverter (manual switch)

  b)) You do not have any limit on power you draw as the inverter power and Eskom power is on the same line and you just draw the power.

 

 

[superdiy]

5 hours ago, jdp said:

2) Bypass the Inverter and have it sit on the eskom line where you draw the power. The following applies.

  a)) If you have batteries and eskom falls away you will have a power failure until you switch back to carry the load off the inverter (manual switch)

  b)) You do not have any limit on power you draw as the inverter power and Eskom power is on the same line and you just draw the power.

But, and there is always a but, if you do the above, and your load is less than what the panels can produce at that point in time, the remainder of the PV generated power will be fed back into the grid, either spinning the disc in the rotary meter in reverse or in case of a pre-paid meter you will either be billed for usage since the standard pre-paid meters cannot detect current flow direction or the pre-paid meter will detect reverse flow and trip.

[Kloon]

So I posed the question about the max output to the Voltronic team and this is their reply based on the 5KW Infinisolar

Quote

In grid mode, the max input and output current(bypass current) can be up to 40A. If the voltage is 230, so the load is 9200W max 

 

 

[Guest]

OK so as we said above is in line then with what they are saying.