Charging outages at the depot: plan reserve capacity and fallback processes for your fleet

A robust plan for charging outages combines technical reserves with a fallback procedure that has been rehearsed in advance. An extra charge point alone does not protect against every fault: if the shared electricity supply or control system fails, the reserve may be affected too. Distinguish failures of individual components from disruptions affecting the entire site, and define for each situation which vehicles must continue operating and how they will obtain the energy they need.

Start with the next departure at risk

The first operational question is not when the installation will be repaired, but which route remains reliably possible until then. A van with enough energy can still be ready for duty despite a failed charge point. Another vehicle may need a decision in as little as an hour.

Create an overview of upcoming departures with current energy levels, necessary recharging and accessible alternatives. Record the latest time for replanning. This is often before the actual departure because backup charging requires extra travel and charging time.

The general fleet charging strategy should already account for alternative charging locations. For a depot outage, however, those alternatives must be described more specifically and tested in practice.

Distinguish faults by their common cause

This table is a structure for risk assessment, not a technical diagnostic guide. Have the specialist designer show which components are shared. Two visible enclosures do not demonstrate two independent supply paths.

Size reserves against a clear operational requirement

Define what capability should remain after a specified failure. Should the entire fleet continue operating normally, or should only particularly urgent routes be protected? Both aims may be sensible, but they create different costs.

A hypothetical example: a depot needs to draw a total of 100 kWh at the charge point during a two-hour window. Two genuinely independently usable units each provide a constant 30 kW under the assumed conditions. Together, they could theoretically deliver 120 kWh. If one unit fails, only 60 kWh remain, leaving a 40 kWh shortfall against demand. The second unit therefore exists but does not protect the full operation.

The calculation uses simplified constant power. Vehicle limits, repositioning and charging behaviour must also be checked. It shows why redundancy must fulfil a defined task and cannot be assessed solely by the number of devices.

Check behaviour without communication

Ask the provider what happens if the internet fails, the backend is unreachable or the control connection is interrupted. Can sessions already in progress continue? Can new sessions start? What power limit applies? Will data be transferred traceably afterwards?

Treat the answers as requirements that need demonstration. Offline charging is not a universal property of every charging card or wallbox. A local fallback mode can operate safely only in the intended configuration. Changes to protection or load limits must not be improvised.

Test the intended state under controlled conditions with the specialist contractor and document it. Also check the return to normal operation. Otherwise, duplicate bookings, missing allocations or a permanently incorrect power setting may only become apparent after the disruption.

External backup charging needs more than a point on a map

Suitable alternatives should be known for every critical vehicle group. Check the connector, permitted vehicle dimensions, access route, opening hours, actual authorisation and the return to the operating location. Cable length, parking position and possible height restrictions matter for vans.

A station shown as available in the app is not reserved capacity. If several of your vehicles switch to it simultaneously during a site outage, a new bottleneck may arise. Plan an order and more than one suitable location where operationally accessible.

The guide to available charging stations nearby explains the limitations of availability displays. For your depot, add a practical test with the intended vehicle and business payment profile. Retain the results as operational information and recheck them after relevant changes.

Agree decision-making and communication

Define who assesses the outage, who replans vehicle use and who commissions technical service. Different people may hold these roles. A shift supervisor should not have to wait for approval from an office reachable only during the day if the next route is at risk.

Set spending limits and approved payment methods for backup charging. If a session is exceptionally paid for privately, the receipt process must be known. Do not assume that an externally paid session can later be added automatically to the central fleet invoice.

Information for drivers should be brief and actionable: the affected vehicle, destination station, time window, payment method and contact if problems arise. A technical error message without a clear task is of little operational help.

Battery storage is not automatically emergency power

In a suitable system, a battery can provide charging power or shift peak loads. This does not automatically mean it can continue supplying power during a grid outage. The design, controls, protective equipment and permitted operating mode must expressly support that function. That backup supply is a specifically designed function is also shown by SMA's manufacturer information on battery inverters and backup power. This does not establish suitability for a specific depot.

Before making such an investment, check the outage duration and energy quantity you want to cover. Even a charged battery has a limited amount of usable energy. Its ability to cover power peaks in normal operation is a different question from supplying energy during a prolonged outage.

Request a clear description of the promised function and suitable evidence. An economically attractive load-management project should not subsequently be labelled an emergency-power concept if that task was never commissioned.

Rehearse the procedure and address weaknesses

Run a planned operational exercise in which a selected charge point is treated as unavailable. Without dangerous interventions, check how quickly affected vehicles are identified, alternative bays assigned and necessary replanning confirmed. Initially simulate a larger outage at the organisational level.

Document lost time, additional costs, missing information and missed targets. Then assess whether a technical reserve, a different charging plan or clearer responsibility offers the greatest benefit. An additional hardware investment is not always the first effective measure.

StromNow Logistics combines depot planning, monitoring, operation and supplementary public charging. For a consultation on an outage plan, bring your critical departures, existing charge points and possible backup locations. Ask for the limits of the intended operation to be stated explicitly and for the fallback procedure to be tested before routine use.