By your own calculation EROI of Battery buses should be about 15-30 (taking diesel EROI as given as it has no source) if you actually apply the vehicle's efficiency; ~85% efficiency for E2E diesel-generator-to-EV. While diesel bus would be around ~21% effiency.
Losses via Gibbs free energy (237 kJ/mol to split H2O) and compression (20% of H2’s 120 MJ/kg.)
Barely cash in on the H2-O2 reaction (ΔH = -285.8 kJ/mol).
Battery buses, powered by lithium-ion cells, hit EROI of 2 to 4.
Redox heavy lithium mining (150 MJ/kg) drags it all down.
Charge-discharge losses (90% Coulombic efficiency)+ 5-10% capacity fade after 1000 cycles.
All trails diesel’s 5-10 EROI and 46 MJ/kg density.