On-grid domestic battery storage

1961Nick

Piddles wrote: »

You'd better get your order in early. Everyone is going to want one once this becomes generally known!

Sales should rocket after 6th April 2020.

joefizz

1961Nick wrote: »

Sales should rocket after 6th April 2020.

If they make it past Jan 2020 ;-)


To put it in context my mate has been on the waiting list since they were announced. He received the papers for it last month...
...still no word on when he will actually get the car...
I suspect he will be visiting more often... just plug the car in there for me....

mmmmikey

Real life took over so it's a while since I posted anything on the PowerVault performance.....

1. Overall position is much as expected, or if anything slightly better. I'm now feeling reasonably confident of breaking even within the life of the batteries, but certainly not expecting this to make me rich.

2. When I bought it, I wasn't sure how it would cope this time of year when I have very low usage, i.e. would switching thresholds mean that I wouldn't be using enough to get the battery to start delivering? In practice this isn't a problem - as long as there's energy in the battery it will continue to deliver pretty much however low the load falls. But this comes at a cost in terms of efficiency, when it's running like this I would estimate that only about 50% of what it's delivering is being used, the rest being lost either in the inverter or going back to the grid as it doesn't adjust quickly enough (or accurately enough) to lower it's output at lower levels. The overall effect on the economics is slightly beneficial, because although it's inefficient running like this, it's "free" solar energy that is wasted.

3. Assuming 1 cycle per day was pessimistic. Even without overnight charging on E7, I'm finding that there are lots of days when the battery charges up in the morning for use at lunchtime and then again in the afternoon for evening use. At this time of year I wouldn't normally use enough energy most days to take advantage of this, but we've had autumn weather in Lincolnshire over the last week and I've been getting 4 or 5 kWh a day use out of my 4 kWh battery, using what little solar energy there's been to take the chill off the house with electric heaters.

4. I had started building an Arduino based circuit to switch the immersion heater off as the solar immersion controller (Solic) and battery don't work well together. But I've found it's so easy to do this manually that I'm not now going to bother. It's been easy to keep the water hot and battery charged, even during the last week of "autumn" weather. As soon as smart metering allows me to move from deemed export payments to actual export payments, I'll ditch the Solic anyway, as I pay less for E7 overnight than I get for export during the day.

Hope this is of interest.....

Solarchaser

Good to know its keeping up with the low demand also.
I've been a bit disappointed of late in the me3000sp, as when off too bed I have 40% of the battery, I expect it will discharge all night. But when house load falls under 150w, it stops discharging and starts using the grid, so I get up to having bought a kw of leccy, even though the battery could have covered it, which is disappointing.

I am however seeing multiple partial discharges during the last month, which is great to see.
The sunny /cloudy/sunny /cloudy days are really making the most of the batteries.

Reed_Richards

Solarchaser wrote: »

t when house load falls under 150w, it stops discharging and starts using the grid,

That seems very poor. Are you sure it's the low power demand and not the time of use mode? If your battery was set to charge from the mains overnight but to take the SOC to only 30% (say) then posibly you might see the same effect, i.e. the battery does not charge or discharge overnight.

Zarch

Solarchaser wrote: »

Good to know its keeping up with the low demand also.
I've been a bit disappointed of late in the me3000sp, as when off too bed I have 40% of the battery, I expect it will discharge all night. But when house load falls under 150w, it stops discharging and starts using the grid, so I get up to having bought a kw of leccy, even though the battery could have covered it, which is disappointing.

I am however seeing multiple partial discharges during the last month, which is great to see.
The sunny /cloudy/sunny /cloudy days are really making the most of the batteries.

Overnight use and covering the nightly baseload is one of the main reasons i'd want a battery. This is slightly off putting!

Is this all batteries standard behaviour or just the Pylontech?

1961Nick

Zarch wrote: »

Overnight use and covering the nightly baseload is one of the main reasons i'd want a battery. This is slightly off putting!

Is this all batteries standard behaviour or just the Pylontech?

I don't have this problem, but my then baseload is over 200w. If there's enough charge, I don't import anything overnight.

Saying that, I'm slightly surprised, because this morning my batteries were supplying just 60w to make up the difference between generation & consumption.

Martyn1981

Zarch wrote: »

Overnight use and covering the nightly baseload is one of the main reasons i'd want a battery. This is slightly off putting!

Is this all batteries standard behaviour or just the Pylontech?

Same here, covering 100-150W night demand is a significant chunk of the import I'd want to displace.

Reed_Richards

Zarch wrote: »

Is this all batteries standard behaviour or just the Pylontech?

I doubt that it is anything to do with the battery; rather a function or malfunction of the inverter controlling it. It does not happen with my system and I would feel very cheated if it did.

mmmmikey

1961Nick wrote: »

I don't have this problem, but my then baseload is over 200w. If there's enough charge, I don't import anything overnight.

Saying that, I'm slightly surprised, because this morning my batteries were supplying just 60w to make up the difference between generation & consumption.

Hi - just to reiterate, I don't have this problem either with the PowerVault. My background / night load is of the order of 50W and it covers that, which I have to say was a pleasant surprise. I think hysteresis comes into play here - i.e. in the case of the PowerVault the battery needs to see a load of 100w to start discharging, but once it's started it keeps going until well below that. Having said that, as I pay < 5p per kWh overnight, it would take a long, long time for me to recoup my investment if I was relying on that at a saving of 3p or so per night Today's been a great example of the battery working well - only about 6kWh generated all day and the battery charging and discharging as the sun has come and gone and only about 0.3kWh of import. Still going strong as I type this.....