Saving Sessions / Demand reduction thread

[tamzzy]

LOL, pulling nearly 18 kW here and dropped the local grid voltage by 6v

do you have a 100A or 80A main fuse?
just curious as i'm getting my AC installed and in theory i can hit 87A at max load everything, but my DNO "don't install" 100A fuses anymore, apparently a slow-blow 80A fuse is sufficient...never heard of that before

 

[Ron-ski]

80A, I've never been concerned about getting it upgraded.

At 230v 80A would be 18.4kW, we're generally around 240v so more like 19.2 kW not allowing for the more intricate details of power calculations.

My Victron routine will limit battery charging, so I don't pass 18 kW, if for some other reason we're drawing too much the Zappi will back off

So I don't really think there is any need for more than 80A, and of course an 80A fuse won't blow for a long time even above 80A (unless substantially above), I forget what the curve is but Google AI tells me I'd have about 4 hours at 100A, which I'm never going to pull.

Maybe if you've got a couple of car chargers both used at the same time, and a large heat pump, but that really needs 3 phase, and the chargers will self limit anyway.

PS. If you do get 100A fuse and are pulling that, then you're running all the connection and cables close to their limits, so its not a good idea in my opinion, especially for any length of time.

 

[Ron-ski]

15.86 kWh, if I'd set the scheduler to end at 15:00 instead of 14:59 then I'm pretty sure we would have hit 16 kWh.

The Zappi even turned off exactly on schedule.

 

[reef]

80A, I've never been concerned about getting it upgraded.

At 230v 80A would be 18.4kW, we're generally around 240v so more like 19.2 kW not allowing for the more intricate details of power calculations.

My Victron routine will limit battery charging, so I don't pass 18 kW, if for some other reason we're drawing too much the Zappi will back off

So I don't really think there is any need for more than 80A, and of course an 80A fuse won't blow for a long time even above 80A (unless substantially above), I forget what the curve is but Google AI tells me I'd have about 4 hours at 100A, which I'm never going to pull.

Maybe if you've got a couple of car chargers both used at the same time, and a large heat pump, but that really needs 3 phase, and the chargers will self limit anyway.

PS. If you do get 100A fuse and are pulling that, then you're running all the connection and cables close to their limits, so its not a good idea in my opinion, especially for any length of time.

Our fuse is 80A aswell. I've found the grid voltage is a bit lower here recently. I suspect the transformer has been tapped down a little as even when exporting at my full 9.68kW, it's barely above about 243v most of the time. It also depends on the meter tails - some properties have 100A fuses but don't really have the tails to support that sort of current for long. Ours were upgraded when we went to a smart meter in 2022. Amazingly in a 2019 new build property we still had a dumb meter.

I have the export margin on the Zappi set so it backs off when the draw from the mains is more than 18kW. It took a while to get this right as Octopus messed up the install of the CT clamp so it runs a bit high (e.g if I'm drawing 5kW it thinks it's more like 6.5kW).

I didn't go for a free hour today in the end and it turned out to be a good decision. From about 12:30 it has been sunny on and off so would have been a real struggle with up to 12kW of PV coming in.

 

[tamzzy]

an 80A fuse won't blow for a long time even above 80A (unless substantially above), I forget what the curve is but Google AI tells me I'd have about 4 hours at 100A, which I'm never going to pull.

that's exactly what my DNO said lol, that the 80A fuse will allow 100A for four hours

i asked as i'm getting A/C installed.
in theory: 7.2kw EV charger, 3.8kw solar inverter charging batteries, 3kw A/c = 14kw
if i did run my kettle and oven at the same time that's another 6kw
= 20kw peak draw, DNO says the 80A slow-blow fuse will handle

 

[Ron-ski]

20kw peak draw, DNO says the 80A slow-blow fuse will handle

They are correct, and the EVSE will reduce its charge rate, as they should have a CT clamp to monitor the grid load.

Kettle is only on for minutes, oven is not constant either, it switches the heating element on and off to maintain temperature, this is called diversity. Add up all the things on your kitchen circuit and I bet they exceed 7kW, and the MCB/RCBO is only 32A.

 

[b0rn2sk8]

AC also isn't going to be pulling max output for more than a few minues either. You'd cook or freeze before the fuse blows.

 

[Mercenary Keyboard Warrior]

Saving session tonight, 6-7pm 68 octo per

 

[tamzzy]

i guess 68 points/kwh, with the free sunday session per two saving sessions is going to be the new normal...

 

[Mercenary Keyboard Warrior]

I now have 3 free hours sessions worth and a half from today, Sunday looks like the best day in the 2 week forecast so I will probably hold off this Sunday again.

Think the following Sunday I will use at least one hour unless it ends up being a really good solar day.

 

[Pyr0m@nI@]{]

Another saving session this evening between 8pm-9pm. (Use less electricity and earn 56 Octopoints.)

 

[Mercenary Keyboard Warrior]

Interesting timing

 

[Ron-ski]

Just 56 points, how low will they go

 

[tamzzy]

i'd be exporting anyway, so every little helps

 

[jackboy]

I thought it was a weird time as well, well past peak and the forecast is for it to still be windy

 

[reef]

Just 56 points, how low will they go

I thought as much when they announced this free hour thing. I tend to export at this time too, so it'll be hard to save much. If it wasn't for the free hour it would barely be worth it.

 

[Mercenary Keyboard Warrior]

I think this current stuff is going to have a different model, quite a risk to Octopus of this costing them a lot

By the time this ends (end of Oct) my default position will be back to not exporting as well, unless the export rate is above the import rate. Just not worth the risk at that point.

 

[Ron-ski]

I always export excess battery between 16:00 to 23:25, so I just tweak the schedules to suite , might as well have the extra bit and the free power hour. I pushed out 7.46 kWh tonight, baseline was -1.76kWh.

It's only very cold days I don't have any spare, and plugging the car in saved quite a few days from peak rate last winter, although I'd need to be careful how much I force discharge in saving sessions when winter does arrive.

 

[Pyr0m@nI@]{]

Another saving session this evening between 6pm-7pm. (Use less electricity and earn 61 Octopoints.)

 

[Mercenary Keyboard Warrior]

Decided not to use one this weekend, unless the weather takes a notable turn for the worse.
But I think by next week I will have 5 hours due so I think I will use one weekly from then on unless its a remarkable weekend.

They did pretty much fill up last weekend so I think its a gamble to save too many hours for later.
Plus obviously we had 3 sessions this week so thats an hour and a half right there. If thats by any way a new normal its going to be close to even use up all I have now.