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Load shedding Backup Advice


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Hi Everyone

 

I would like to get a backup system just for the essentials, lights and PC, TV. So my initial plan is was to get a 3kw Kodak Inverter, with a Fox ESS LVE2600 2.56kWh 48V Battery. Just take in consideration continues load will most likely be 2kw or even less. I was looking at the Kodak 3kw inverter 48V, but noticed it is not much more expensive to get a 5kw inverter.

 

So thinking in terms of future upgradeability, I am considering getting the 5kw inverter, on the same battery. This way I can just add another battery in future, perhaps another FOX ESS LVE2600 in the near future, and perhaps look at at solar after that. I will most likely limit what is connected to 2kw peak in the beginning, even though i will be running a 5kw inverter, so I argue the battery should be sufficient for a start. What are your thoughts. I need to get an inverter very soon, and currently this is only what the budget allows.

 

This is obviously not off-grid solution, but I reckon 5kw on the house (kitchen not connected and no geysers), with extra or bigger battery capacity would be sufficient running a home (no geyser and kitchen). 

 

Looking forward to see the comments.

 

 

 

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  • 3 weeks later...

Hi @SkilliePower

Since no other comments are offered, I'll mention the basics - at the risk of stating the obvious, since you asked no specific questions.

I'm not going to address the technical issues about specific products, but mention general principles:

By "you" I am addressing the household, since everyone needs to work together at making the implemented plan succeed.

Assuming 20% minimum State of Charge (SOC), one 2.5kWh battery at 2kW discharge rate will last max 1h, regardless of whether it is drawn from the kitchen, bedroom, lights, etc. Obviously, the less you draw, the longer the battery will take to discharge.

Assuming 2.5h of loadshedding per event, you will need to limit power drawn to below (2000Wh/2.5h=) 800W (on average) to last from 100% to 20% SOC on the 2.5kWh battery. The lower the start SOC, the lighter the average load needs to be to last, or the shorter the duration until the inverter switches off. If past stage 4, loadshedding may extend to 4.5h per event.

Back to your post: have you quantified the load for early morning/evening loadhsedding? (What is included in your  requirement - lights (how many?) TV, radio, alarm system, bedside appliances, etc?) If a permanent installation, consider wiring the DB to supply just those essential sockets to prevent 'accidentally' using battery power on a hairdrier.

How does the math add up - both power supply/demand and finances? And rather be a tad too generous than too accurate, since there always seems to be some form of scope creep *after* budgeting for the requirements.

I hope you find what you need and that it works for you.

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@LoodPyp

Gave a good reply on the actual load on whatever inverter you had in mind. For on grid and back up you could consider the heart and here one can look at the cheaper Kodak King that can blend the grid with PV once you get to it. These units can be operated in a Solar/Grid/Battery mode as well as Solar/Battery/Grid. Nearly double the cost Sunsynk/Deye is a great inverter which I rate as a control system combined with inverter. It just has so many options to configure. Both these can also contribute to savings by running loads from PV during the day and just takes from the grid what PV cannot provide. This can keep the battery well charged from when there is sudden LS.

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On 2022/06/08 at 11:47 AM, SkilliePower said:

Just take in consideration continues load will most likely be 2kw or even less.

The specs on the fox battery recommend 25A (1200W) discharge and 50A (2400W) max but the 50A will probably shorten the battery life drastically. It is a good idea to go for the bigger 5KVA inverter for future expansion, but extra intervention need to be put in place to make sure the battery don’t get damaged before you get time to add a second one. I would recommend if you do go this route fit a 6A (1380W) circuit breaker between inverter and essential DB to ensure the circuit breaker trip before the battery takes a hammering. If you go for a Sunsynk you don’t need the 6A breaker and can set the maximum battery discharge on the inverter and limit it to the 25A (1200W) recommended setting. I have only one Pylontech 3.5KWH and have limited it on the Sunsynk to the recommended Pylontech setting. 

 

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Hi Gents, 

A very noteworthy addition I would like to make to this conversation. The Kodak OG7.2 and OG10.0 share this same maximum battery discharge limit. That means a smaller battery can also be paired to this machine. So that in loadshedding you can limp along if you are disciplined enough. In loadshedding if you exceed this discharge limit the inverter will trip. When the Grid is available the inverter will draw from the Grid the shortfall. 

The modern Kodak inverters are also Hybrid blenders however, they cannot grid feed and don't have the Essential and Non essential split. That very important task would be the work of a good electrician. 

If the Kodak is installed correctly, one can stagger the loads and add some heavy items to the Essential loads like the geyser and stove. It all depends on how the installation is done. @Scorp007touches on a good point. These Kodak Range of inverters are more affordable when in comparison to the Sunsynk. However, their operation and type of installation differ greatly. 

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Hi Gents

 

Sorry for the late reply, but thank you for all your inputs. Perhaps it would be wise to see if I can stretch the budget a little, perhaps see if I can double up on the batteries or buy a single bigger battery for now. I don't want to damage the battery, but initially I may get away with it if I can be disciplined enough until I get a second battery.

Lots to think about, but i am concerned about the scope creep Loodpyp... 

 

 

 

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