"Phantom drain"—the slow loss of charge when an EV is parked—has gone from forum myth to quantified operational cost for fleets and households. Modern EVs are always-on computers with telematics, security, and thermal management systems that sip energy even when wheels are not turning. At Energy Solutions, we analyse real-world data from thousands of vehicles to benchmark standby losses by brand, software configuration, and climate.
Phantom drain (also called vampire drain) is the loss of stored energy in an EV’s traction battery while the vehicle is parked and not being driven. Unlike self-discharge in older chemistries, most modern drain is due to active systems:
In practice, OEMs offer a spectrum of behaviours:
| Subsystem | Typical Power Draw (W) | Notes |
|---|---|---|
| Base electronics & BMS | 5–25 W | Depends on sleep state and polling intervals. |
| Telematics & connectivity | 2–15 W | Frequent wake-ups and constant LTE can dominate drain. |
| Security & cameras | 10–80 W (when active) | Sentry/guard modes can be the single largest contributor. |
| Thermal conditioning | Variable (bursty) | Short bursts to avoid extremes in hot/cold storage. |
Using anonymised telematics from mixed fleets and opt-in consumer datasets (mostly 2023–2025), we estimate average daily energy loss while parked under "normal" user behaviour. Table 2 below illustrates typical ranges by configuration. For units and measurement context: standby/low-power consumption is typically characterised as average power (W) over time when loads fluctuate (e.g., IEC 62301 principles summarised by the U.S. Department of Energy: DOE).
Quick conversion: kWh/day ≈ (average W × 24) / 1000. Example: 20 W average ≈ 0.48 kWh/day; 80 W average ≈ 1.92 kWh/day.
| Scenario | Climate | Typical Drain |
|---|---|---|
| Deep sleep, limited app polling | Temperate | 0.1–0.3 kWh/day |
| Always-connected, frequent checks | Temperate | 0.4–1.0 kWh/day |
| Security/camera mode enabled | Urban, temperate | 1.0–2.5 kWh/day |
| Cold storage with battery heating | Sub‑zero winters | 0.5–2.0 kWh/day (weather dependent) |
Brand-to-brand differences are narrowing as OEMs tune software, but we still see 2–3× variation between best- and worst-behaving configurations. OTA updates over the past three years have systematically reduced drain for some models.
For an individual driver, phantom drain is often a range annoyance more than a bill shock. At $0.20/kWh, an extra 0.5 kWh/day amounts to roughly $36/year. For a fleet of 1,000 vehicles, the same behaviour can mean:
| Average Drain (kWh/day) | Annual Energy (MWh) | Annual Cost @ $0.15/kWh | Annual Cost @ $0.25/kWh |
|---|---|---|---|
| 0.3 | ~110 | $16k | $27k |
| 0.7 | ~256 | $38k | $64k |
| 1.5 | ~548 | $82k | $137k |
Beyond cost, phantom drain erodes usable range on departure. For example, an EV with a 60 kWh pack and 3 days of high-drain parking (1.5 kWh/day) loses ~4.5 kWh—roughly 7–10% of usable capacity for many models. For airport parking or remote depots, this matters.
A mid-range EV left for 10 days at an airport with camera-based security mode continuously enabled lost ~18–20% SoC. Owner telematics showed ~1.5–2.0 kWh/day consumption, mostly from cameras and connectivity. After software updates, enabling a dedicated "long-term parking" mode cut losses roughly in half.
A European sales fleet (220 EVs) initially reported an average of 0.8 kWh/day of phantom drain due to frequent app polling and legacy telematics. By reconfiguring fleet software to poll less often and enabling eco-sleep profiles, average drain dropped to ~0.35 kWh/day, saving roughly 40 MWh/year.
An urban car-sharing operator relies heavily on always-on connectivity and location tracking. Phantom drain sits toward the upper end of the spectrum (~1.0–1.8 kWh/day), but is treated as a necessary cost of availability. The operator mitigates impacts by favouring models with efficient telematics hardware and by staging fast top-ups during low-demand hours.
Climate and software maturity drive significant differences:
In our datasets, OTA updates between 2022 and 2025 reduced average phantom drain by 20–50% for some popular models without hardware changes—demonstrating that software is now a major lever in EV standby efficiency.
Not all standby consumption is "waste". Some loads are delivering direct value:
The objective is not to reach zero drain but to achieve **smart, configurable standby** where users and fleets can choose their position on the comfort–security–efficiency trade-off.
We expect several trends to shape phantom drain over the rest of the decade:
For operators, tackling phantom drain is largely a software and behaviour problem. Practical steps include:
| Levers | Low-Drain Setup | High-Drain Setup |
|---|---|---|
| App polling | Batched, few times per day | Frequent wake-ups, continuous polling |
| Security mode | Targeted, event-triggered | Always-on cameras and sensors |
| Sleep profile | Eco/deep sleep after idle timeout | "Always connected" priority |
For most 2024–2026 models in temperate climates, 0.1–0.4 kWh/day with energy-saving modes enabled is typical. Sustained losses above ~1 kWh/day without security modes or harsh weather merit investigation.
Enable any available storage or deep-sleep mode, disable high-drain security features unless necessary, and park with a comfortable SoC buffer (e.g., 60–80%). In very cold or hot climates, parking in covered or temperate locations can reduce thermal-related losses.
Yes. Apps that poll vehicle APIs frequently can keep systems awake. Fleet managers should consolidate integrations where possible and prefer platforms that support event-based or batched polling.
Small, steady draws are usually less of a concern than repeatedly cycling to very low SoC. The bigger risk is leaving an EV parked for long periods at low SoC such that phantom drain pulls it toward 0% and deep discharge. Storage at moderate SoC in eco-sleep modes is generally fine.
Request standby consumption metrics from OEMs, include them in total cost of ownership models, and favour vehicles that support granular sleep configuration and high-quality telematics APIs.