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Question on performance in relation to charge

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Hello!

I was wondering at what point do you start to lose performance when it comes to how much battery charge you have. From the butt dyno I haven't felt much of a difference through 30-70% charge range which is where I normally keep it. But I've heard that if you don't have 90% charge you're losing performance.

Thanks!
 
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Hello!

I was wondering at what point do you start to lose performance when it comes to how much battery charge you have. From the butt dyno I haven't felt much of a difference through 30-70% charge range which is where I normally keep it. But I've heard that if you don't have 90% charge you're losing performance.

Thanks!
It actually depends more on battery temperature and State Of Charge more than just SOC alone.

I have seen as much as 462 KW “Max Discharge” and as little as 432 KW “Max Discharge” with 90%+ SOC.

That can be as much as .3 seconds in the 1/4 mile.

Full preconditioning is essential for max performance with the Model 3 Performance.

Some people have equal performance with lower states of charge because they aren’t preconditioning fully which severely limits their max acceleration.

My testing has shown that absolute max performance can only be achieved with an essentialy fully charged and fully preconditioned battery.

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Here's one dyno for the performance model: Tesla Performance Model 3 Dyno Testing At Various SOC - Mountain Pass Performance . Here's a model 3 AWD with the performance boost: Since the motors don't pull full power until ~65kph you won't feel much before that, unless SOC is really low.

Yes, as someone else points out that is in ideal temperatures. If the battery's even remotely cold, like under 30-35C or maybe more, you will start losing a bit of power. In a real winter day here at -20C it doesn't matter the SOC, if I don't precondition I get 100hp :D

The AWD model doesn't have a preconditioning option for performance like the Performance model does as we don't have track mode. Preconditioning the cabin only bring the battery to 10-15C or so. Preconditioning navigating to a supercharger will bring it up though, to 50C which might be over the top just to get some performance...

When I got the car I kept my SOC high as I wanted all the performance I could get. Now I stay in the 40-60% to help battery degradation. It's all about trade-offs.
 
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Thanks for your answers everyone! That makes a lot of sense, wish I could precondition the battery; but wouldn't preconditioning the battery degrade it or damage it if you're using it too often? Or is it essentially the same thing as letting your engine and transmission warm up in an ICE car?
 
Thanks for your answers everyone! That makes a lot of sense, wish I could precondition the battery; but wouldn't preconditioning the battery degrade it or damage it if you're using it too often? Or is it essentially the same thing as letting your engine and transmission warm up in an ICE car?

Both of those things (letting the engine warm up in an ICE and pre conditioning the battery) add wear and tear on the component.
 
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Yep... I had started to write up a long text but I'll jut say: everything is compromise. Peak performance might not align well with battery health for example. You pick what's relevant for you.

Thats always the thing, everything is a compromise. From the OPs other cars (and mods) listed in their signature, at least for their other cars, they skewed toward "performance" and away from "longevity". Unless those cars were also garage queens, they likely were, let say, "driven" with a capital "D" ;)
 
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Seems like most people want data from drag racing. I'm actually curious about autox or road racing. At what SOC do you start noticing lap times drop. And does track mode cooling exacerbate the issue more than help?

Seems like it would be nice to have a mode where it doesn't cut power at all until it drops to 30% or so.
 
Seems like most people want data from drag racing. I'm actually curious about autox or road racing. At what SOC do you start noticing lap times drop. And does track mode cooling exacerbate the issue more than help?
@The Other Dan Track Mode's preemptive cooling is precisely to help the car last as long as possible before heatsoaking. Which a stock M3P will do.

Now if you upgrade the M3P's cooling in all the ways needed to never heatsoak (including with supercharging/DCFC between sessions), then maybe you'd want to avoid preemptively cooling for better power output. However at that point you surely have your own controllers involved in managing your cooling system, and can ignore/override whatever cooling Track Mode is requesting.

Seems like it would be nice to have a mode where it doesn't cut power at all until it drops to 30% or so.
Are you asking for an accelerator map that limits max power output, in order to have a more consistent amount of power available? Yes that seems like it could be nice to have for track day use. Actually we do have it, it's called Chill mode. 😁 Mostly kidding of course - I'm sure Chill mode is too limited for what you have in mind.

Edit: I'd love it if we could program our own accelerator maps for the M3P, like can be done easily with ECU reflashing on drive-by-wire ICE cars. Tesla could even make it a builtin feature using the touchscreen - how cool would that be?
 
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Yeah, you're not interpreting the power reduction right. The battery voltage drops.... At least just for that it's not possible to maintain the maximum power it can provide when at 100%. Unless as someone suggests you start withless than the battery 's max, you would be able to sustain that longer... At lower soc I'm sure there's other factors at play, probably protecting the battery...
 
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Yeah, you're not interpreting the power reduction right. The battery voltage drops.... At least just for that it's not possible to maintain the maximum power it can provide when at 100%. Unless as someone suggests you start withless than the battery 's max, you would be able to sustain that longer... At lower soc I'm sure there's other factors at play, probably protecting the battery...
It's not a DC motor and it's not opening gates 100%, plus actual voltage is under load which depends from SOC, temperature and actual load. A lot depends on inverter firmware. It literally never at 100% of what battery can give, because that would kill battery very quickly. It just takes into account all sensor data and defines how much to open the gate at the moment to satisfy driver's request and battery longevity.
 
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@The Other Dan Track Mode's preemptive cooling is precisely to help the car last as long as possible before heatsoaking. Which a stock M3P will do.

Now if you upgrade the M3P's cooling in all the ways needed to never heatsoak (including with supercharging/DCFC between sessions), then maybe you'd want to avoid preemptively cooling for better power output. However at that point you surely have your own controllers involved in managing your cooling system, and can ignore/override whatever cooling Track Mode is requesting.


Are you asking for an accelerator map that limits max power output, in order to have a more consistent amount of power available? Yes that seems like it could be nice to have for track day use. Actually we do have it, it's called Chill mode. 😁 Mostly kidding of course - I'm sure Chill mode is too limited for what you have in mind.

Edit: I'd love it if we could program our own accelerator maps for the M3P, like can be done easily with ECU reflashing on drive-by-wire ICE cars. Tesla could even make it a builtin feature using the touchscreen - how cool would that be?
That would be a good idea to be able to define throttle curves in track modes.
 
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@Mash , I don't know that much about motors, you might be right. I'm just pointing out that as our battery discharges, the voltage of each cell, and thus the total voltage of the pack lowers. Since kW power is volts * amps, if you have less volts you get less power available unless you can raise amps. If we assume that at 100%soc and WOT the car uses all power available from the battery then that max power will reduce as the battery depletes. Maybe I'm wrong and the motors have beeen chosen to accept slightly less max power than a full battery...
 
Seems like most people want data from drag racing. I'm actually curious about autox or road racing. At what SOC do you start noticing lap times drop. And does track mode cooling exacerbate the issue more than help?

Seems like it would be nice to have a mode where it doesn't cut power at all until it drops to 30% or so.

Autocross: No noticeable issues with power at most venues, since speeds are low. At least from 95% to 70% nothing noticeable.

For a track day you will get power limited from battery heat before you lose power from SOC if you don't have the cooling on. Maybe not on a cool day, would certainly be nice to have more options than just MAX FANS ALL THE TIME MAKING MAX NOISE