Diy battery backup/power
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Frankychops

Original Poster:

2,022 posts

38 months

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

7,499 posts

248 months

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

10,819 posts

145 months

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

Original Poster:

2,022 posts

38 months

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

Original Poster:

2,022 posts

38 months

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

10,819 posts

145 months

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

14,368 posts

55 months

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.