Backup loads

[up_north]

Many inverters have an output for backup loads in the event of a power failure. How does this work? Is it literally a cable going from the inverter into the relevant consumer unit way - eg downstairs/upstairs lights?

Ta all.

 

[binky]

Many inverters have an output for backup loads in the event of a power failure. How does this work? Is it literally a cable going from the inverter into the relevant consumer unit way - eg downstairs/upstairs lights?

Ta all.

Generally involves a dedicated circuit directly connected to the inverter for items you don't want to fail under power cut, so can be hard to retrofit in an existing set of circuits.

 

[up_north]

Generally involves a dedicated circuit directly connected to the inverter for items you don't want to fail under power cut, so can be hard to retrofit in an existing set of circuits.

Thank you,

 

[binky]

Thank you,

The inverter has a dedicated output port, usually limited to around 16amps max, some people use this to backfeed the house board, but you need to be careful of loadings if you do that ie turn off everything bar essential items only. It's better if you can wire a dedicated cct, like fridge, freezer, and gas boiler - NB, despite what your teenage kids might think, WiFi is not essential

 

[up_north]

So in that instance, say you had the oven, kettle, etc on which took you over 3.6kw and there was a power outage, if the inverter then kicks in what will happen if the demand is too great - something will just trip?

 

[binky]

Probably, kettles tend to be around 2.5kw by themselves, so I would assume the inverter would self protect and shut down the UPS, which is why I was talking about dedicated ccts earlier. You can get larger inverters with higher outputs of course, but the higher the load the less time the battery will last.

 

[johnb2713]

NB, despite what your teenage kids might think, WiFi is not essential

That may depend on how you communicate with the inverter to start it running in backup mode, my Growatt uses the WiFi connection!

 

[binky]

That may depend on how you communicate with the inverter to start it running in backup mode, my Growatt uses the WiFi connection!

true, that'll keep the kids happy then

What some people do is wire the UPS output to their main board, but with an inline isolator, so that they can shut down appliances except the essentials then connect the UPS funtion, which strikes me as a lot easier then rewiring stuff. I would also think it's worth fitting a larger battery if regular power cuts are expected, and setting a maximum discharge so that it always keeps say 60% charge in the battery, although that isn't so good for getting the benefits of having a battery in the first place.

 

[up_north]

Thanks guys. We don’t have regular power cuts. Was just curious.

 

[Trendywendy]

Hi there, we have solar panels and a battery system. Naturally, In the event of a power cut neither the panels or battery work. If we had the EPS system fitted, would this mean that we would have use of the panels again in the daytime as well as the limited amount of battery usage?

 

[johnb2713]

Hi there, we have solar panels and a battery system. Naturally, In the event of a power cut neither the panels or battery work. If we had the EPS system fitted, would this mean that we would have use of the panels again in the daytime as well as the limited amount of battery usage?

It depends on your inverter, most have an emergency (backup) output for this purpose. On my system, I can operate a changeover switch and the power to my house is restored until the panels stop working or the battery is flay. The output is reduced somewhat on most inverters.

 

[Trendywendy]

Thank you for the response. The inverter is a Fox-ess and we have been offered the option of the EPS amendment to the system, but didn’t know whether it meant the panels would still work. This would be a great advantage if so.

 

[johnb2713]

Thank you for the response. The inverter is a Fox-ess and we have been offered the option of the EPS amendment to the system, but didn’t know whether it meant the panels would still work. This would be a great advantage if so.

I dont know about that inverter setup, i'm sure others will be along shortly that can advise.

 

[michael8554]

Whatever method you use to power some circuits from the PV and battery during an outage, you must be certain that there are no situations where power can get back into the grid, for the protection of "line workers".

 

[bladerunnerpv]

I know nowt about this presently but very interested
In case it's useful I found this on my travels ...
https://www.deegesolar.co.uk/eps_for_solar/

hope this helps

 

[Trendywendy]

Thanks for your responses and yes the link was useful to clarify what our EPS requirements would be.

 

[Mrjmegson]

I know nowt about this presently but very interested
In case it's useful I found this on my travels ...
https://www.deegesolar.co.uk/eps_for_solar/

hope this helps

I've just read the EPS link, and I'm shocked to read that in EPS mode, the inverter will only take power from batteries, and not from any solar generation.

I'd ideally like a way to fool my inverter into thinking the grid is live, but actually to fit an isolator between my meter and consumer unit and turn off the grid. I assume I'd need something that could generate a 50hz pulse to do that.

It seems Tesla, Victron and SolaX can all do it.

 

[binky]

I'd ideally like a way to fool my inverter into thinking the grid is live, but actually to fit an isolator between my meter and consumer unit and turn off the grid. I assume I'd need something that could generate a 50hz pulse to do that.

One of my customers fitted a changeover switch to the meter tails and external socket for a generator. He had a lot of freezers full of homegrown produce he was determined not to lose.

 

[Mrjmegson]

It's amazing no one has made a separate unit like the Tesla Gateway, but to work with non Tesla products.