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The Quiet Argument Over State-of-Charge at Loading
By Vignesh D. · March 5, 2026 · 5 min read
No public standard exists for the state of charge of an EV when it rolls onto a vehicle carrier. The argument behind closed doors is intense — and the number matters more than most people realise.
There is no international rule on what state of charge a battery-electric vehicle should be in when it is loaded onto a RoRo. Some OEMs prefer 50–60% to enable delivery test drives. Some operators want 30% or lower to limit thermal energy on board. The argument is real and almost entirely private.
Why SoC matters thermally
- Stored energy is roughly linear in SoC — more charge, more available energy in a runaway event.
- Peak cell temperature in runaway rises with SoC, raising the propagation risk to neighbours.
- Some BMS firmware paths are more sensitive at high SoC, particularly under vibration.
30%
Operator-preferred loading SoC (informal)
50–60%
OEM-typical delivery SoC
~2x
Available energy ratio between 30% and 60% packs (rule-of-thumb)
The number is going to become a published policy somewhere — either at IMO, at a class society, or in a major operator's loading manual that becomes a de-facto industry standard. Worth watching.
Sources
- Larsson, F. et al. — "Toxic fluoride gas emissions from lithium-ion battery fires," Scientific Reports 7, 10018 (2017).
- IUMI — "Risk mitigation for the safe ocean and short-sea carriage of electric vehicles" (Sept 2025 revision).
- Vehicle Carrier Safety Forum (VCSF) — published guidance on EV loading practice (2024–2025).
- ICCT — research notes on EV logistics and state-of-charge in maritime transport.
- [VERIFY: 30% operator-preferred and 50–60% OEM-typical loading SoC — operator/OEM-internal practice; no public consolidated source.]
- [VERIFY: "~2x available-energy ratio between 30% and 60% packs" — engineering rule of thumb; depends on chemistry and cell architecture.]