Prepaid meter

Settings → Prepaid meter is for a grid supply on a prepaid meter, where a token adds units to the meter and the meter counts them down. One unit is one kWh. It is off by default: until you switch it on, nothing appears on the dashboard, nothing is counted and nothing is stored.

What Epilykos does, and what you doCopy Anchor Link

Epilykos cannot buy a token, load one, or read the meter. It has no connection to either. You do those things by hand, and the buttons only record what you did:

• Record recharge: after you have bought and loaded a token, enter the units it gave. You can also enter what you paid, and the price per unit is worked out.
• Correct balance: read the number off the meter and type it in. You can do this at any time, whenever the estimate has drifted from the meter. Epilykos sets the balance to your number, and it can learn from the difference.
• Undo last entry: takes back the latest recharge or correction, if you entered it by mistake.

Between those, Epilykos works out the balance itself. It takes the grid energy it measures off the balance:

balance = last reading you gave + units you recorded since − grid energy used since

The first time, enter what the meter shows now (Set the balance) so there is a number to count down from.

SavingCopy Anchor Link

The switch, the two warning levels and who can see the balance are one form: change them, then press Save. The button stays off until something changes, and nothing is sent before you press it. The recharge, correction and undo buttons are different: they are not settings, and they take effect as soon as you submit their dialog.

What it countsCopy Anchor Link

The energy comes from the daily grid import counter (the metric mapped to that role on the Metrics page). If there is no such counter, it uses the grid import power instead. If neither is mapped, the page says so.

The meter and your inverter never agree exactly, so the balance is an estimate. When you correct it, Epilykos can use the difference to work out how much the meter counts for each kWh it measures, so later estimates drift less. The page shows what the last correction found, and the box Use this to improve later estimates in the dialog turns that off for one correction.

WarningsCopy Anchor Link

Both are optional:

• Warn when units left fall to: a number of kWh.
• Warn when days left fall to: days left is the balance divided by your average grid use over the last 7 days.

When the balance reaches either level, Epilykos raises the event Prepaid meter low, and Prepaid meter out of units when it reaches 0. They do nothing until you add an event rule for them, so you choose where the message goes. Each is sent once, not on every poll, and again after the next recharge.

Who can see the balanceCopy Anchor Link

The dashboard can be seen without signing in, so you choose:

• Everyone who can see the dashboard (the default): the balance, days left and what was used are shown on the cards, and published as metrics.
• Only me, when signed in: the balance is kept out of the published metrics, and the cards show nothing to anyone who is not signed in. Other cards and charts cannot show the balance either.

Recharges, corrections, the list of entries and these settings always need you to be signed in, whichever you pick.

Where it showsCopy Anchor Link

• The Prepaid meter card: the units left, a bar, days left, facts, the latest entries and the buttons.
• Optional text at the top right of the Grid status card: the units left and the days left, red from your warning level.
• The metrics prepaid_balance (kWh), prepaid_days_left, prepaid_used_since_recharge (kWh) and prepaid_cost_per_unit, which any other card, chart or notification can use (unless the balance is private).

The entries are kept like your other settings, so a backup and restore keeps them.