Diy battery backup/power

[Frankychops]

looking at this

https://uk.eco-worthy.com/products/eco-worthy-16kw...

No solar, just simply charge at night off peak(i've got 3 phase), ROI on a diy install looks to be 2 years.

Anyone done similar? or links/threads?

[theboss]

If your objective is to provide backup to grid connected circuits you need something that can switch from grid-following to grid-forming in an outage - that looks like it's for standalone off-grid use only.

Are you looking to backup a single phase or all 3?

It's not DIY but I use the Sigenery system for exactly this and installed it initially without solar. It can form a synchronised 3-phase grid, has independent phase control for significantly unbalanced loads and fails over in an outage instantly. It's not cheap but then neither is anything else that can do this.

[silentbrown]

theboss said:

If your objective is to provide backup to grid connected circuits you need something that can switch from grid-following to grid-forming in an outage - that looks like it's for standalone off-grid use only.

It's an odd bit of kit, that. The inverter has independent AC In and Out connections, so AFAICT the entire house load flows through it (and presumably, is therefore limited to 10KW/40A). So it can never export to grid.

[Frankychops]

theboss said:

If your objective is to provide backup to grid connected circuits you need something that can switch from grid-following to grid-forming in an outage - that looks like it's for standalone off-grid use only.

Are you looking to backup a single phase or all 3?

It's not DIY but I use the Sigenery system for exactly this and installed it initially without solar. It can form a synchronised 3-phase grid, has independent phase control for significantly unbalanced loads and fails over in an outage instantly. It's not cheap but then neither is anything else that can do this.

Never to the grid. Effectively the whole house load is connected, it either by passes itself or uses its battery, so super simple. I’ve a phase that runs most of the house(others run a lean to area and another the garage etc).

[Frankychops]

silentbrown said:

theboss said:

If your objective is to provide backup to grid connected circuits you need something that can switch from grid-following to grid-forming in an outage - that looks like it's for standalone off-grid use only.

It's an odd bit of kit, that. The inverter has independent AC In and Out connections, so AFAICT the entire house load flows through it (and presumably, is therefore limited to 10KW/40A). So it can never export to grid.

Exactly. That’s its major plus point, as most of my usage then ends up effectively being at the off peak costs(not allowing for any losses)

[silentbrown]

Frankychops said:

Exactly. That s its major plus point, as most of my usage then ends up effectively being at the off peak costs(not allowing for any losses)

I'd have a few concerns:

10KW isn't that much - typical house mains fuse is 100A = 23KW (this could be an issue if the 10KW is an AC input restriction and in includes the ~5KW battery charging. If you have battery being charged, 3KW fan heater and a kettle boiling you're probably over 10KW)

Single (complicated) point of failure. If the device goes belly up, you lose all power to the house.

Earthing. AIUI you can't use the incoming mains earth connection, so a proper earth spike is essential. A proper sparky could advise?

Payback. Too many factors at play always, but tariffs (and peak/offpeak differentials) are never guaranteed. Plus, factor in efficiency losses (is there also a
loss just when going grid in to house out??) and potential reduced charge rates at low temps.

[OutInTheShed]

Frankychops said:

looking at this

https://uk.eco-worthy.com/products/eco-worthy-16kw...

No solar, just simply charge at night off peak(i've got 3 phase), ROI on a diy install looks to be 2 years.

Anyone done similar? or links/threads?

I think your maths are way out.

It's a 15kWh battery.
If you exactly use the whole capacity 365 days of the year and save 16p a unit, you save under £900 a year.
Reality is, some days you won't use 16kWh, particularly if it's current limited and doesn't do high use things like induction hob.

[Frankychops]

I've based it on my annual peak usage, less charging costs and % for loss, against what it can deliver.

If if i'm 50% out, its miles ahead of any other route

[biggiles]

Frankychops said:

I've based it on my annual peak usage, less charging costs and % for loss, against what it can deliver.

If if i'm 50% out, its miles ahead of any other route

There are a few other threads on a similar topic. I have a big battery+solar system here, and it runs across all 3 phases.

Are you trying to "save money" or keep freezers/internet on for a few days in a power crisis, or run the house totally normally for a few hours if there's a short power cut? The first two are relatively easy.

[OutInTheShed]

It doesn't really look like a DIY proposition anyway.

[Frankychops]

biggiles said:

Frankychops said:

I've based it on my annual peak usage, less charging costs and % for loss, against what it can deliver.

If if i'm 50% out, its miles ahead of any other route

There are a few other threads on a similar topic. I have a big battery+solar system here, and it runs across all 3 phases.

Are you trying to "save money" or keep freezers/internet on for a few days in a power crisis, or run the house totally normally for a few hours if there's a short power cut? The first two are relatively easy.

Ideally it’d just run the house during peak hours. Upto the max power of the inverter. From what I’ve read its power in, load out, when battery gets low it’s a seamless switch to incoming. Same as most battery units. Effectively it’ll save money and offer backup. For not too much cash or effort

[biggiles]

Frankychops said:

biggiles said:

Frankychops said:

I've based it on my annual peak usage, less charging costs and % for loss, against what it can deliver.

If if i'm 50% out, its miles ahead of any other route

There are a few other threads on a similar topic. I have a big battery+solar system here, and it runs across all 3 phases.

Are you trying to "save money" or keep freezers/internet on for a few days in a power crisis, or run the house totally normally for a few hours if there's a short power cut? The first two are relatively easy.

Ideally it d just run the house during peak hours. Upto the max power of the inverter. From what I ve read its power in, load out, when battery gets low it s a seamless switch to incoming. Same as most battery units. Effectively it ll save money and offer backup. For not too much cash or effort

That's very do-able then. Factor in that you only want to use 50% of the battery capacity, so it lasts a long time. It can pay back pretty well, especially if you're on an EV tariff and have good rates to arbitrage. But professional installation costs can be significant, even if it's not particularly complex wiring. It's an interesting mix of high-power lithium batteries and 3-phase electronics, so not a typical area of experience for normal electricians.

[autocrazy]

Frankychops said:

looking at this

https://uk.eco-worthy.com/products/eco-worthy-16kw...

No solar, just simply charge at night off peak(i've got 3 phase), ROI on a diy install looks to be 2 years.

Anyone done similar? or links/threads?

Hi OP

I am contemplating exactly this. Have you gone ahead with this proposition? I mainly want it to be DIY to keep costs low and payback period short, with flexibility to add solar panels in future. One combination I am considering is this one https://ebay.io/m/urHTF7 which is cheap at £2k delivered!

[silentbrown]

autocrazy said:

Frankychops said:

looking at this

https://uk.eco-worthy.com/products/eco-worthy-16kw...

No solar, just simply charge at night off peak(i've got 3 phase), ROI on a diy install looks to be 2 years.

Anyone done similar? or links/threads?

Hi OP

I am contemplating exactly this. Have you gone ahead with this proposition? I mainly want it to be DIY to keep costs low and payback period short, with flexibility to add solar panels in future. One combination I am considering is this one https://ebay.io/m/urHTF7 which is cheap at £2k delivered!

No way on earth that something that sits between your incoming mains feed and your consumer unit is a DIY job.