[APP][Pro] Piggy Bank

iPhone 14 Pro.
I see that it works in dev tools/browser

When charging multiple hours using schedule from this app my Easee charger stops charging my Tesla at every whole hour, and then restart again about 5 min after the full hour. Anyone else experiencing this?

You should be able to resolve this if you enter the app setting, go to the menu “Devices” / “Meter reader” and increase the “Cross hour smoothing” (Norwegian: “Utjevning mellom timer”). The default value is 20% which may be a little bit low.

I can probably increase the default value, what do you think? What factor works best for you?

Than you for your quick reply. I have increased the value now, and hope it will fix the issue :blush:

Is it possible to compensate for outside temperature? so that when it is warmer outside the set point is reduced and when it is colder the set point is increased?

Interesting proposal, I wonder if I should add that possibility.
Meanwhile, you might be able to use virtual thermostats as a relay as I think they are able to add offsets…

I tried setting it to 35%, but the issue happened again now. Trying 55%, which sounds a bit high to me.

Do you plan to support solar energy investeres? And then make it so that the household try to use as much of the prododuction itself instead of sending to the grid? Might required that the user also use a power meter with this app.

One action that could be done would be to increase the charging limit of a car. This is something that could also be usefull with the price as input, as I use the price level to decide if I should temporarly increase the charging limit.

After testing with 55% it «only» limited the charger to 1,6kw the first exact 5min after the next full hour, before going back to its usual 5,8kw. So no stop in the charge, but still unnecessary.

The spikes in power usage can be many times the average usage, it depends on your house. Now, here is a dump of my available power (to stay within a 5kWh budget) for the last 6 hours:

At the start of every hour, I have 5 kW available because the app doesn’t know how much power will be used for the rest of the hour. Since the average usage is a bit below 5kW it means that at the end of the hour, a lot more than 5kW will be available to still be within the 5kWh budget. This is as you can see capped at the main fuse so no more than 25kW will be available. Nevertheless, this shows that at the end of every hour, the spikes can go up by 400% for me and the app will still not turn off devices. Thus increasing it by 55% at the start of the hour isn’t very high compared to the end of the previous hour. You may have to go up by 200% before you notice any difference.

Yes, the planned changes are listed here: Add suport for electricity production · Issue #2 · frodeheg/no.sparegris · GitHub

Please check if this suits your needs…

Thank you for a very good answer! I put the reserved power significantly higher, and it seems to work fine.

Regarding solar inverters I only suggested as I was thinking it would be something usefull for many, but sadly I dont have a solar installation myself.

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Hi @frodeheg
Im trying to make the app ignore my warm water device at night time by setting it to «alltid på» at that profile.

Even when doing this, it will still be turned off to prevent going to a new effect level. I Control my Car charger with Tibber to Get 20% off, so i want sparegris to keep my VVB on at nigth time, and then Tibber can adjust the charging effect when needed

Hi, you’re right, the text regarding “Always on” in the app is a bit misleading and should be updated.

Currently, how it works is that a device marked with “Always on” will not be switched off as long as there are other devices to switch off. Thus if a situation occurs where the app has turned off all other devices and still cannot meet the power limit then it will start turning off “Always on” devices.

The intent has been to remove this source of confusion in the version where I introduce the time schedule. The same goes for the override functionality for “Always on”.

With time schedules a true “always on” will be added while the old “always on” is renamed to “preferred on” to better reflect what it actually is doing. (Meanwhile, until the “time schedule” is complete, I can change the text to “Preferred on” as that fits the functionality better.)

I have explored a few options that you could potentially do but the current version of the app seems to have no way to accommodate your request.

EDIT: When you want Tibber smart charging to adjust the top usage I propose you do like this:

  • Create a flow “Change max hourly usage to 50000 Wh” that runs before charging is started
  • Create a flow “Change max hourly usage to 5000 Wh” (or whatever Wh you normally use) that runs when charging is completed

This will make sure Tibber is the only source to modify your top usage for the duration of the charging.

Generally speaking though, having two sources to adjust the amount of energy usage will only lead to conflicts, so it doesn’t sound like they should be on at the same time.

Thus, I think your current best option would be to let piggy control the car charger, or I would like to improve this function if it currently doesn’t work for you.

What do you mean by 20% off if you use Tibber to control the car charger? Do you get a discount just by using their app? If so, then that would be impossible to compete against and I wonder if your best option would be to:

  • Create a flow that changes the piggy operation mode to “Disabled” when using the charger.
  • Create a flow that changes the piggy operation mode to “Day/Night/etc.” when done using the charger.

About Tibber.
From what I’ve been told, since Tibber is your “operator” they know your total usage and on what hours you spent them. For those who opt to let Tibber control their Easee charger, they also know how many kWh your Easee charger(s) have charged any given month, and hence the mean price for those Easee-kWh.

They subtract the kWh charged with Easee from your total usage, and now have 2 price categories on your household. Your “charging price” and your “other usage” price. Tibber guarantees that your charging price will always be minimum 20% less than your “other usage”.

“Tibber smart charging” does what Piggy Bank does, charge when the price is low. So as long as the prices vary during the day, it’s easy for Tibber to get below 20% of “other usage”. Happens by itself most of the time. But if the user insist on charging on the most expensive hours, or the prices don’t vary that much, the user can end up with less than 20% difference between “charging price” and “other usage”. Tibber then has to pay the difference out of their own pocket.

It’s not that hard to beat 20% of your “other usage” if you use Piggy either. Maybe you could implement stats to show us, which in worst case proves me wrong? :sweat_smile:

I’ve read that Tibber also has load balancing. So it’s basically a choice to let Tibber or Piggy control your charger, if I’m not missing anything crucial.

Ah, thanks for the explanation.
Hmm… this makes the prices per hour kind of indeterministic as they won’t be decided before you have completed the day. How do they actually pay for this, will they “increase” the price if you’re more than 20% below? I suppose the 20% only account for the electricity price and not the surcharge… Does this mean that those rare cases we have seen with negative prices (such as tomorrow) will get a 20% discount on the negative price (e.g. increased price)?
And is there still a direct link between the prices per hour for the “other usage” and Nordpool?

…how does this work with solar cells? … and if you have a house battery? I figure “other usage” can be manipulated quite much and I suppose you don’t want Tibber to reduce the price of your solar production by 20%.

Naturally, I cannot give a guarantee myself, but I can give an estimate how many % below/above the “other usage” you will be if you charge at different hours, but I am not sure whether that is sufficient for users to prefer piggy over tibber smart charging.

The app is currently without price info on automatic mode.

I know, it’s because the provider entsoe.eu does not have updated prices today for some reason.

The prices are available on Nordpool though, but their policy do not allow me to fetch prices from there. I had a discussion with them on email about fetching the prices from there but they do not allow me to unless I pay 5000 Nok per month, which is unacceptable for an open source project.

You may use the “Strømregning” app to fetch the prices instead as Piggy allow input from there. That app fetches directly from Nordpool so prices should be available.

Ok, but how do I make it fetch the prices from “Strømregning” app? And would it be able to make it so that it uses that app as a backup input (if installed) and provider entsoe.eu has not published the prices?

If you want to use the app “Strømregning” to fetch prices then, after installing and configuring it you enter the piggy setup and

  • Click on the menu “Advanced” → “Cost”
  • Expand the box for “Usage part”
  • Change price type from “Spot price” to “External”

It is not possible to use it as a backup, it’s either one or the other.

It seems like the situation has been resolved now though, it has never lasted this long before, but I guess the timing was bad being the middle of the weekend.

EDIT: There is one way around nordpools policy though that would let me fetch the prices from nordpool directly in cases like this, it would be something like this:

  • If entsoe.eu does not have any future prices, I can add a manual button that can be clicked to fetch the prices from nordpool (automation is against their policies so this is the only way)
  • I could possibly fetch nordpool prices when you open the setup interface too as that is a manual action, though it will not be as transparent to the users why it has to be that way.

Do you think a “repair” button would be a good improvement?

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@frodeheg
Hi.
I was trying to get my Home Assistant dashboard to show Piggy Banks price-level using MQTT.
However, the price levels seem to be broadcast in the form of numbers (prispunkt 2-5 it looks like) instead of cheap, expencive etc.

Not sure if this is something you can controll?