Title: Combining 7-10 KVA UPS, Bacterial Modules & Photovoltaic Panels: Is it Efficient?

kosmos99 wrote:

The three-phase ongrid inverter will not be excited by the voltage from a single-phase UPS or Offgrid

It's just about powering the house in the event of a blackout .
So we preventively cut off the network and put UPS on the house.
I didn't understand what it was at first either

Such an on-grid mixed with an off-grid island. rotfl.

bestboy21 wrote:

So we preventively cut off the network and put UPS on the house.

Wouldn't it be better to power your home with a UPS all the time?
Then the ATS will not be needed.
Of course UPS or off with the right power.

kosmos99 wrote:

bestboy21 wrote:

So we preventively cut off the network and put UPS on the house.

Wouldn't it be better to power your home all the time via a UPS?

Better but 4 times more expensive.

Why? If it's the same UPS. Even better for the battery, because their state of charge will be monitored all the time.

kosmos99 wrote:

Why? If it's the same UPS. Even better for the battery, because their state of charge will be monitored all the time.

If this UPS was to work as on-line, it would have to transfer all the power (and God forbid 3 phases), here we are entering industrial UPSs, you can ... everything is possible.

See post (1) from the author's topic:

Doom wrote:

I'm thinking about connecting a 7-10 KVA UPS

Added after 3 [minutes]:

Therefore, cost-effectively, offgrid may be better.

And it is best to separate current-consuming circuits that do not have to work in the event of a power failure from the network. Then 5kVA single phase should be enough.

kosmos99 wrote:

See post (1) from the author's topic:

Doom wrote:

I'm thinking about connecting a 7-10 KVA UPS

Added after 3 [minutes]:

Therefore, off-grid may be better off-grid.

And it is best to separate current-consuming circuits that do not have to work in the event of a power failure from the network. Then 5kVA single phase should be enough.

This is some solution.

Everything is ok, but one detail is still missing for the PV to work when the power supply from the grid fails. Therefore, the UPS cannot be fully separated and could theoretically power the grid together with the PV during a power outage, which is why automatic backup switches are needed. With the cost of PV and UPS, the cost of switches is small. In general, I want to have a plan to know what to complete successively to build a fairly reliable system. I can also buy a few panels and add a classic off-grid, but what will it give? The point is to use all the elements of the current infrastructure and build something that will work efficiently and reliably. If the hybrid inverter can handle it, then ok, I can use it, if a separate charge regulator and a separate converter will be better, it's also ok. If you have any idea or even specific devices that can be nicely customized, I will gladly take your advice I'll just add that I don't live there, so the system must be autonomous, I'm preparing this house to live there when I'm tired of working in corporate. Heating is only electric, both central heating and DHW, I heat it up to about 10 degrees in winter, so that nothing freezes or moldy - that's why I installed PV. Electricity costs in the amount of PLN 800-1000 per month in the winter knocked down. That is why I want PV to supply the grid with surpluses, in the winter PV alone will not be able to afford heating, so it will draw on surpluses from the summer. in September alone, I have about 600 kWh worked out, and there is only a fridge + a small CCTV server. So about 400 kWh will be available. Even if I fire 2 radiators of 2kw each, it will be a bit of a drag, they will not go all the time to the max, but always.

Doom wrote:

Everything is ok, but one detail is still missing for the PV to work when the power supply from the grid fails.

It's a linden with microwaves, because they are probably under the panels and we don't have any DC voltage pulled out anywhere.
With a standard inverter, you could think about replacing it with a hybrid one, or switching panels to Offgrid. Now there is no way to bite it too much.

Well, that's why I wanted to use switches to disconnect the panels from the mains and connect them to the "internal network" with a UPS / inverter that will simulate the voltage from the supplier. In general, this was the idea for the UPS to power the whole house, i.e. it was connected between the supplier and the receivers. The switches would switch PV from pre-UPS to UPS and vice versa. But then the UPS will not charge from the PV. Only problems Therefore, the PV could be connected before and after the UPS, but I don't know if the UPS can be powered by the electricity it produces from the batteries.

Doom wrote:

that's why I wanted to use switches to disconnect the panels from the mains and connect them to the "internal network" with a UPS / inverter that will simulate the voltage from the supplier.

This will be rather difficult, if at all possible to implement. Even if the microwaves wake up, they will probably damage the UPS, because it will then get voltage at its output.
The only way out, but also rather difficult to implement, is to disconnect the panels in front of the microwaves and put them on offgrid.

Well, it will be easier to buy additional 4-8 panels for off-grid and charge the batteries also from microwaves if there is power from the network. In case of failure, disconnect the on-grid and the network from the provider. That is, give a hybrid inverter and connect the network and ongrid as input, then we lose charging from microwaves in the event of a failure, but there will be additional panels that will charge the batteries anyway.

Which batteries are best to use and how to count them to be enough?

Doom wrote:

Well, it will be easier to buy additional 4-8 panels for off-grid and charge the batteries also from microwaves if there is power from the network.

Approx. Only the inverter must have this option to select charging hours.

Doom wrote:

In case of failure, disconnect the on-grid and the network from the provider.

There's no need. You power ongrid before offgrid, i.e. it will turn itself off and on without collision.

Doom wrote:

So give a hybrid inverter and connect the network and ongrid as input

Only the network, if there is sun, you will indirectly use ongrid, which will then work for this network.

Doom wrote:

in case of failure but there will be additional panels that will charge the batteries anyway.

You will use these panels all the time, because the offgrid will continuously supply the loads.

Doom wrote:

Which batteries are best to use and how to count them to be enough?

It depends on the length of the emergency operation, the capacity of the panels and the load. After discharging the batteries to the offgrid input, the generator can be switched on, in addition to powering the loads, it will also charge the batteries.

I plan to use a Growatt inverter, 2kWp panels and AGM batteries, initially 4 pieces 100Ah. If it's ok, I'll add another 4.
For batteries of this type, when it comes to service life, temperature and lack of deep discharge are very important. For a temperature of 20C and buffer operation, it is 12 years, but at 40C it is only 3 years, i.e. the battery loses 40% of its capacity. The same is true for discharge cycles. At 100% discharge we have only 300 cycles, 50% 500, and at 30% already 1300.
Therefore, I will try to discharge them to a maximum of 20% during normal operation and up to 50% in an emergency. There will be no warehouse from this huge one, but the power from the panels will be used. There are also gel and lithium batteries, but the price of the latter is five times higher and they can be discharged much deeper and more often. Overall, they seem to be the most profitable. But I don't want to spend too much right now.

Old topic but still relevant?
I have it like that:
1. mechanical switch utility or UPS. (unfortunately the break is less than a second but it's there)
2. Afore solar inverter (single phase - up to 3 phase I don't have UPS)
3 UPS sinline 1200 VA (pure sine)
4. Afore smartblocker between the UPS and the inverter - makes sure that the inverter only produces as much as the household consumption and the voltage does not increase)

The UPS works without load, so on a small battery (2x7Ah) it works for over 6 hours. It is only used to "synchronize" the inverter with the grid (UPS). As there is no "sun", it discharges quickly even in the light itself. I plan to add a "charger" to the batteries outside of the UPS to continuously charge the batteries from solar power. Then it could walk away from the power grid (from dawn to dusk) and not just 6 hours. I had to add an additional load to the output of the UPS to smooth the sine, I experimentally reduced it to a 5 W incandescent bulb.

I tried with a fideltronik 3000VA UPS and an external MB4821 battery but it does not give a sine (steps) and the Afore inverter does not recognize it as a network. It does not generate electricity as if there is no power at all. A separate battery module was to be powered from an inverter on the other side of the smartblocker. The battery module has output only from the battery (constant current), but the problem is the lack of sine at the output.

These are experiments, not normal operation of the mains. People who do not have the appropriate knowledge (those with knowledge too) may be at risk, including the loss of their lives and the lives of bystanders. I advise home electricians against such experiments.

I've done it like this for now:

Power supply from the mains + microinverters are connected to the disconnector - on the network side, the disconnector is connected to the power supply of the DELL 8KW UPS, the ups is connected as the power supply of the house installation. What does it give me? The surplus goes to the network and is later returned at night. When I have a power outage from the mains, the house still works normally - the UPS supports the whole thing - the panels do not produce. It's not a perfect solution, but it's good enough for now. I also have a generator that I will want to connect via an automatic switch + several batteries charged directly from other panels with a 2500KW full sine constant power inverter.

Hello,
I'm digging up some old stuff, but I'm having the same dilemma.

The solution is Victron Multiplus II, but only if the PV installation is reported to the ZE.

If I did not want to report the PV installation to the ZE, I only have off-grid.
The problem is that I want to use Enphase microinverters that I would like to plug into the emergency power supply of the house, e.g. Sinus converter. In microinverters I set the network profile to Zero Export and in theory everything works and I am separated from the ZE grid. But in practice, the Zero Export mode needs time to measure and analyze before it lowers PV production, so some excess energy will be delivered to the output of the inverter or UPS for a short time anyway, i.e. there will be a momentary higher voltage.

The question is, are there any emergency power devices that have protection against short-term power supply to the output?