One of the most common mistakes fleets make when electrifying is treating EV charging as a hardware problem. Buy chargers, install them, plug vehicles in, and assume the rest will sort itself out. Unfortunately, it won’t.
Gerardo Zarazua de Rubens, Senior Vice President at BetterFleet outlines the what load management is, and the best strategies that can be employed to ensure efficient and cost effective EV fleet charging.
In reality, a defining challenge of depot charging is load management. That’s how much power the site can safely use, how that power is shared across vehicles, and when energy is consumed. Get this wrong and depots face tripped breakers, vehicles that are not ready for service, and energy bills that spiral out of control. Get it right and constrained electrical capacity turns into predictable operational capacity and a competitive advantage in areas where grid capacity is already limited.
Why load management matters more than fleets expect
When people talk about smart charging, load balancing, or energy optimisation, they are usually describing the same underlying objectives. The goal is to manage site load so charging remains reliable, efficient, and affordable.
There are three reasons this matters:
Reliability: If total site load exceeds what the electrical connection or internal infrastructure can support, protection devices trip and charging stops. It does not matter how many chargers are installed or how large the fleet is. A dark depot charges nothing.
Image: BetterFleet
Operational readiness: Fleets need vehicles to be ready for service. That means ensuring the right vehicles receive the right amount of energy within tight dwell windows, often overnight.
Cost control: Energy pricing varies widely by time of day, and peak demand charges can quietly dominate operating costs. Poor load management locks fleets into expensive rates and unnecessary infrastructure upgrades. Those cost dynamics are about to sharpen further. The UK is rolling out Market-wide Half‑Hourly Settlement (MHHS), which will settle consumption in 30‑minute blocks, making the timing of depot charging far more visible on your bill.
The hierarchy fleets often ignore
Load management becomes clearer when viewed as a hierarchy of constraints rather than a single site limit. Every depot has multiple electrical limits, and none of them can be exceeded.
At the top is the site limit, defined by the grid connection. Below that are sub-boards and distribution panels, followed by internal feeders, charger groups, and finally the chargers themselves.
Site to sub-board to internal feeder to charger group to charger.
A common mistake is assuming that if the site has headroom, everything downstream is fine. In practice, internal feeders and panels are often the smallest constraints, and they are where overloads actually occur. Fleets discover this the hard way when a single wash bay or HVAC load trips a breaker even though EV charging appears to be within limits. Other building decarbonisation projects, like heat pumps, can also have a significant impact on load availability.
Good load management respects every layer, not just the top one.
Static limits are safe but often wasteful
Many depots rely on static load caps aligned to known constraints or tariff periods. This approach is simple and conservative, and it does prevent overloads.
The downside is inefficiency. Static limits assume worst-case conditions at all times, which leaves usable capacity sitting idle for much of the day. Fleets then compensate by installing more chargers, upgrading infrastructure earlier than necessary, or accepting lower operational flexibility.
Static limits are a starting point, not a strategy.
Dynamic limits unlock capacity if you can see what is happening
Dynamic load management adjusts limits in real time based on measured site load, sub-board utilisation, or feeder capacity. This is where fleets unlock meaningful value.
The key requirement is visibility. If EV chargers share electrical boards with buildings, workshops, wash bays, or HVAC systems, then total site load must be measured, not estimated. Without real-time metering or safe headroom assumptions, a depot can appear compliant from an EV perspective while still being one load spike away from a shutdown.
Dynamic control does not just protect infrastructure. It allows fleets to add vehicles faster, defer costly upgrades, and operate closer to true capacity with confidence.
Charging strategy matters more than charger count
Once limits are defined, the next question is how power is shared across vehicles. Many depots default to whatever strategy the charger installer suggests or whatever happens to be the out-of-the-box setting. That decision quietly shapes daily operations.
Using single charging strategies like equal sharing or first in, first out work for predictable depots with long dwell times. They break down quickly when departure times vary, vehicles block one another, or certain routes are mission-critical.
More advanced fleet operations use a mix of strategies or priority-based strategies that allocate power according to operational rules such as departure time, state-of-charge deficit, route criticality, or emergency readiness. The point is not complexity for its own sake. It is alignment with how the fleet actually runs.
Batteries do not charge in a straight line
Another common blind spot is battery behaviour. EV batteries don’t charge in a linear fashion; they follow a similar curve, with a fast “bulk” phase followed by a slower “soak” phase as the battery approaches full charge.
Without load-following logic, depots waste capacity by continuing to allocate power to vehicles that can no longer accept it efficiently. That power could be redirected to vehicles still in the bulk phase, improving total throughput without increasing site load.
Fleets that understand this distinction stop thinking in terms of charging vehicles and start thinking in terms of allocating power where it has the highest operational value.
Energy optimisation is an ROI lever, not an optional extra
Smart charging must account for when energy is used, not just how much. Time-of-use pricing, peak demand charges, and utility signals all shape operating costs.
The best-performing fleets shift flexible charging into lower-cost windows while still meeting readiness targets. They actively avoid demand spikes rather than discovering them on the bill and create more predictable monthly energy costs.
Advanced energy capabilities like local storage, on-site generation, and grid interaction can add further resilience and savings, but only if the fundamentals are in place first.
What fleets should take away for their electrification strategy
One of the main reasons that electrification fails is because power is not managed as an operational system.
Fleets that succeed to not only manage power, but make it into a competitive advantage, do three things well:
- they manage load in real-time at every electrical layer, not just the grid connection
- they choose charging strategies that reflect real operations, not defaults
- they optimise charging considering multiple variables, such as readiness and cost
When those pieces come together, limited electrical capacity becomes predictable operational capacity. And that, more than charger count or vehicle specifications, is what determines whether an EV fleet works day after day.
