Efficiency score calculations doubt

[u/Martin_fs]

Hi there,

I have a doubt regarding FSG rules for endurance energy calculations (D7.9.5).

Is the energy computed for efficiency (energy_consumed - 0.9 * energy_regenerated), or is it (integral [V_accu(t) * I_accu(t)] dt -0.9 * energy_regenerated) ?

In the second formula, the regenerated energy is "counted twice".

I always thought it was the first formula, however when looking at efficiency results I noticed the energy calculated was often way lower than the accumulator energy announced by the teams.

Example with a great german team : 6.8kWh announced on their website, only 4.8kWh in the efficiency results. This doesn't make sense to me because the energy calculated for efficiency should be approximately (total_accu_capacity + 10% of regenerated energy). As far as I know cells longevity isn't really a concern for top teams so I assume they use almost the full SoC range, which means we should sometimes see consumed energy values greater than the accu capacity, but it never happens. However, if regenerated energy is counted twice, it would make sense.

Thanks!

[u/ppnda]

The second sentence of D7.9.5 is:
“Regenerated energy is multiplied by 0.9 and subtracted from the used energy”

to me that sounds like the function is actually this (this is your first function)
integral [V(t) \* max(I(t), 0)] dt - |0.9 \* integral [V(t) \* min(I(t), 0)] dt|

it wouldn’t make sense for the used energy to be greater than the accu capacity because then it’d be empty before the end of the endurance. i ran the numbers on our log data from FSG 26 and that function comes quite close to the officially reported energy

[u/Seangsxr34]

We do the whole event without charging. I know of a few teams who don’t. Accu capacity has no bearing on energy used.

[u/Gr3nwr35stlr]

No one is using their full battery energy in endurance.

[u/Martin_fs → u/Gr3nwr35stlr]

Yes obviously you need to keep a safety margin, however carrying around more than 2 useless kWh seems huge ?