Technical guide to cloud EMS

AgeVolt EMS distributes available power among charging vehicles. Its design depends on the electrical installation, measurement and operating rules. This guide explains cloud-based control for electrical designers, building managers and integrators, from a home connection to a site with several levels of distribution.

For practical examples at home or at work, start with the introduction to AgeVolt EMS. Instructions for operating a local SmartSystem remain in its separate manuals.

Total consumption and the charging budget

A control point is a part of the installation with a shared limit, such as the main supply, a distribution board or a cable feeding chargers. It can contain connectors and subordinate points. Each vehicle respects the constraints along its entire path through the installation.

Example: A building has a total limit of 100 kW, while equipment other than charging currently uses 80 kW. Approximately 20 kW remains for vehicles. If the building system directly supplies a 20 kW charging budget, EMS does not deduct the same 80 kW from it again. Total consumption at the main supply, by contrast, includes both the building and its charging vehicles.

On a mixed-load branch, consumption by other equipment must also be known. A meter or building system provides this information; alternatively, the building system supplies an already calculated charging budget. A branch containing only managed chargers can operate with a configured limit. Here EMS accounts for the limits it permits, rather than relying only on vehicles' temporarily lower consumption. A separate meter is optional; electrical protection remains necessary.

Hierarchy and combining measurements

A typical installation may be organised as follows:

• Main supply: A and kW limits, BMS data.
  • Distribution board: A limit, meter.
    • Branch A: A limit, chargers only.
    • Branch B: A limit, chargers only.

Available power at the main supply does not remove a smaller cable's limit. If 60 kW is available across the site but a car park has its own 20 kW cap, that car park can use at most 20 kW. If the shared available capacity falls to 15 kW, the car parks share that smaller amount.

A point may use one or several meters. Measurements may be added only if they form the required whole without counting the same load twice. Two separately measured branches using 30 and 20 kW total 50 kW. A main meter that already includes both branches must not be added again. Independent supplies retain their own current limits even when their power is assessed together.

Amperes, kilowatts and phases

The number of phases used by a vehicle and the connector's phase wiring order are different facts. A single-phase vehicle does not necessarily draw from L1 at the main meter. The design records phase mapping between meter and connector. EMS takes this into account; it does not physically switch phases. Spare capacity on L2 does not automatically allow more current for a vehicle connected to an overloaded L1.

At approximately 230 V and a power factor of 1, 18 A single-phase is about 4.14 kW. The same power is delivered by 6 A three-phase, but the loading of each phase differs. A/kW conversion can use valid, time-smoothed voltage measurements. The 230 V value used in examples is indicative.

The power limit is used for ongoing regulation. It is not a separate optimiser for 15-minute demand peaks.

Meters and measurement assemblies

Choose sensors according to current, the opening needed for the conductor or busbar, and compatibility of the whole assembly. A sensor's measuring range does not determine the permissible current of the protected circuit.

SmartMeter uses the TECO C-EM-0300M measurement unit connected to SmartSystem through the local CIB bus. SmartSystem transfers data to the cloud. CIB is not Ethernet. Depending on configuration, one SmartSystem can serve several measurement points.

The JRF MOI 333M-115 Rogowski assembly has an integrated integrator, a 333 mV AC output and a 5 V DC auxiliary supply. Conventional passive sensors do not require auxiliary power. The current rating “1,000 A” alone is therefore insufficient to determine the wiring.

Another MQTT meter can be connected through an agreed data format or conversion adapter. MQTT support alone does not establish compatibility: quantities, units, phases, timestamps and energy-flow direction must be checked. For the supplied model's exact wiring and parameters, see the meter and accessory technical documents and SmartMeter documentation.

Integration with the building system

A BMS is a building management system. It can provide total consumption, set the charging budget, or do both. Integration defines point identities, units, timestamps, access rights and the meaning of status responses.

This table describes integration functions with an agreed configuration. The specific device, data schema and register map must be verified for the installation; an interface alone does not mean automatic compatibility.

REST requests enter the platform's integration layer. A direct connection to the EMS control process is not needed. With Modbus, SmartSystem acts as a local gateway to the platform: Modbus TCP uses TCP/IP, usually over Ethernet; Modbus RTU typically uses a serial RS485 link. Client/server roles, registers and quantity mapping are defined in the installation's integration documentation.

Digital inputs represent agreed power levels rather than continuous measurements. The design also specifies the meaning of input combinations and interrupted signals. An I/O module by itself is not an electricity meter.

Request acceptance, application of a limit in EMS and the vehicle's physical response are three distinct states. A register or API response is not a measurement proving that consumption has fallen.

Fixed cap, BMS and the manual backup

The technical cap comes from the electrical installation. The operating budget can come from the BMS or a stored manual value. The stricter constraint always applies, together with limits at other points, the station and the vehicle.

1. Before the first valid BMS request, the stored manual backup value applies.
2. A valid BMS budget takes precedence for 10 minutes after its latest confirmation or a heartbeat confirming that budget's validity.
3. A confirmation may contain the same budget. It renews validity without unnecessary repeated charger commands. Consumption telemetry alone does not renew it. Invalid or replayed old data does not extend it either.
4. After ten minutes without renewal, the manual backup applies. Editing that value while the BMS is active changes the backup, not the active BMS budget.
5. A fresh valid BMS budget automatically takes precedence again.

A zero budget also expires. If the BMS does not renew 0 A or 0 kW and the manual backup is positive, charging may resume when validity expires. To keep charging paused, renew zero or configure a zero manual backup. Zero pauses charging; it does not turn EMS off or electrically isolate the station.

Example: the manual backup is 10 kW. At 08:00 the BMS requests 20 kW and at 08:05 confirms validity. With no further renewal, 10 kW applies from 08:15. A fresh valid 15 kW budget at 08:17 automatically restores BMS precedence. Technical caps apply throughout.

Priorities, minimums and vehicle rotation

The default priority is normal; the other levels are low and high. Normal priority may receive more power while a low-priority vehicle retains its functional minimum, if it fits. High priority may pause lower-priority charging. Protected basic charging in ECO with a minimum remains when all such minimums fit within capacity.

Priority can belong to a connector and to a recognised vehicle. If the connector accepts vehicle priority, the higher of the two applies; otherwise the connector's priority applies. The specific installation must support vehicle recognition. A public connector therefore need not accept an unfamiliar vehicle's individual priority.

An AC limit is zero or a whole number of amperes starting at 6 A. If there is insufficient current for every vehicle's minimum, some wait. For example, six single-phase vehicles on the same phase with a 35 A charging budget cannot each receive 6 A. One possible allocation is five vehicles at 7 A and one paused.

Within the same priority, rotation considers lower kWh delivered since charging began first, followed by longer waiting, earlier start and a stable final order. Between rotation times, continuity for already charging vehicles is favoured. The order is reassessed on the hour and half hour in local time. This is not a 30-minute timer from connection or a promise that every vehicle is swapped at every boundary.

A vehicle drawing no power despite permitted charging can release capacity to waiting vehicles after 120 seconds and two usable zero readings. A pause imposed by EMS itself is not treated as lack of demand. See charging priorities for further examples.

AC and DC on a shared supply

AC control accounts for the phases used and their current. DC is controlled in power and respects each output's maximum and the station's shared cap. Two outputs of a station capped at 80 kW may, for example, receive 50 + 30 kW; each does not automatically have 80 kW available.

DC power delivered to the vehicle is not the exact AC input drawn from the grid. Input also includes losses and auxiliary consumption. A mixed-load supply is therefore assessed using its measurement; conversion of output power into input amperes is an estimate. A zero charging limit may not eliminate the station's own consumption. The specific station and vehicle are verified at commissioning, including the shared cap of a multi-output DC station.

Solar generation, time and electricity prices

COMFORT does not grant high priority. It uses surplus before other economically controlled charging and can also import from the grid. Protected ECO minimums that fit do not lose their basic charging. COMFORT ends when switched off or when that charging session ends.

Example: with 2 kW surplus and a vehicle minimum of about 4.1 kW, ECO with a minimum may make up the difference from the grid. Surplus only waits. Increasing above the ECO minimum requires surplus to cover the entire ECO load, not just the added increment.

A weekly schedule sets modes by day and time. More intensive charging can depend on a low tariff or a threshold for the current electricity purchase price. All simultaneously required price conditions must be satisfied. If a required input is missing, the selected fallback economic mode remains in force; MAX is not thereby enabled. The purchase price in EUR/kWh excluding VAT uses a price source, multiplier and surcharge; it need not equal the full billed electricity price.

Solar surplus is assessed as a power balance across phases. This does not mean zero grid import at every instant or advance scheduling of future cheapest hours based on departure time or a battery target. Read more about solar generation and ECO and cost reduction.

Response and outages

EMS assesses recent history, load variation and the expected effect of commands already sent. It does not overwrite raw readings with estimates. Power decreases and increases have different response times; control timing does not guarantee end-to-end latency across the meter, cloud, station and vehicle.

If a vehicle draws 16 A under a permitted cap of 20 A, reducing the cap to 18 A does not itself remove 2 A of consumption. A change to 14 A predicts a decrease of about 2 A on the phases used. The result is assessed using new readings and changes in other loads.

A valid BMS budget does not replace live measurement where that point requires it. EMS complements electrical protection; it does not replace the electrical design, correct wiring or inspection.

Design and commissioning checklist

1. Draw the hierarchy of control points and supplies. Specify what each meter covers and which readings may be added.
2. Define technical A/kW caps, AC/DC types, shared station caps, phases and their mapping.
3. Select meters and sensors. For BMS, clearly distinguish total measurement from the budget reserved for vehicles.
4. Agree quantities, units, energy-flow direction, data timestamps, update intervals and staleness thresholds for every source. Current-based control needs phase currents; total kW alone cannot replace them.
5. Configure manual backup budgets, renewal of the BMS budget's 10-minute validity, priorities, modes and time/price conditions.
6. Test phases, flow direction, a reduced limit, zero, power restoration, simultaneous branches and the vehicle response. Distinguish requested value, accepted limit and actual consumption.
7. Test loss and recovery of measurement, BMS and station communication, including what happens when a zero budget expires.

Exact addresses, registers, data fields and credentials belong in separate integration documentation. Electrical wiring follows the documentation for the exact model supplied.

Downloadable guides

• AgeVolt EMS product guide — Slovak-language PDF: practical use at home, at work, for fleets and car parks.
• AgeVolt EMS technical guide — Slovak-language PDF: measurement, limits, integrations and design inputs.
• Energy measurement — equipment documents: datasheets and manuals for specific assemblies.