Performance vs SOC - any actual test data?

[elpwr]

Spark's battery pack has a nominal voltage of around 370 and I've read about 425 when fully charged. Anyone found any test data on acceleration, etc on a fully charged pack vs a depleted one?

I'm pretty sure I can feel reduced power, especially as SOC drops under 40% or so.

 

[kevin]

Spark's battery pack has a nominal voltage of around 370 and I've read about 425 when fully charged. Anyone found any test data on acceleration, etc on a fully charged pack vs a depleted one?

I'm pretty sure I can feel reduced power, especially as SOC drops under 40% or so.

Can you see any difference in the indicated power on the dash display?

It is quite probable that the power is reduced at the lower states of charge although I can't say I've noticed it.

kevin

 

[elpwr]

Hard to say for sure. I always see 120kw power draw at full power, at least for a few seconds, when near fully charged. Often only about 116kw after about half discharged. I'm not too sure you could actually feel the 3% or so power reduction. But it might be measurable with a stopwatch acceleration run.

 

[Zoomit]

Today I saw 120kW when at about 30% charge. I'm fairly certain it'll go up to 120kW from a standstill at any charge level above the low charge power limit. The available power from the motor trails off at higher speeds and so it may be that the available motor power trails off sooner at lower charges though.

 

[elpwr]

Probably not much, if any of an issue at all. I was just curious about it.

I have a good bit of experience with lithium batteries in RC model airplanes. Been using them for about eight years now. But they are lithium polymer chemistry. Their power delivery remains mostly linear down to <20% SOC. Just like lithium ion, their life is shortened considerably by deep discharges and extensive time at full charges. Unlike lithium ion (I hope) their life is generally a couple of hundred cycles.