Yes. As you can see outside ~42-72mph (~50-80mph for 85kWh) or you won't get full power. And this seems to be a simplified/idealized curve. I would bet that flat part still has some small variations in power below peak.
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Power limited at 50% SOC, only when flooring it?
- Thread starter Stoneymonster
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- Driving Dynamics Model S
Yes. As you can see outside ~42-72mph (~50-80mph for 85kWh) or you won't get full power. And this seems to be a simplified/idealized curve. I would bet that flat part still has some small variations in power below peak.
Talking about this?
At 100mph there is ~150/~220/~225 kW available.
Hmm I always wondered why even when fully charged I would get the limiter when punching it. If I'm reading it right this chart explains why above 75mph I'd start to see the limiter line. Is this an official chart from tesla or based upon consumer observance or mathematically calculated somehow?
It is also the standard way that induction motors work. An ideal motor will work with the straight lines you see in the graph. In reality they approximate the line very closely.
I'm pretty sure the limiter is not indicating what the motor is capable of, but it's a battery protection. If the voltage drops under a certain level the battery gets permanently damaged. A good battery management monitors each cell (or cluster of parallel cells) and limits the current draw when the voltage drops too low to protect the battery. What this lower limit is depends on state of charge, battery temperature, and probably also on how aggressive the battery has been discharged before. There are probably other things that also play in (motor and inverter temperature). The battery management monitors all these things and limits the power and shows it as the orange line.
I have seen it come on a few times when the SOC was pretty low. Around 50 miles left. I have seen it come on during hard acceleration at higher SOC and oddly enough the power indicator showed higher power than the limiter. It usually disappears again quickly, but it will stay on when the SOC is low. In those cases I would recommend not pushing the accelerator any harder then you really need. Going hard on the battery when it's SOC is low is really bad. The limiter just prevents instant damage. You should be going easy towards the end of the battery capacity.
I have seen it come on a few times when the SOC was pretty low. Around 50 miles left. I have seen it come on during hard acceleration at higher SOC and oddly enough the power indicator showed higher power than the limiter. It usually disappears again quickly, but it will stay on when the SOC is low. In those cases I would recommend not pushing the accelerator any harder then you really need. Going hard on the battery when it's SOC is low is really bad. The limiter just prevents instant damage. You should be going easy towards the end of the battery capacity.
I'm getting the same limiter after two seconds of acceleration in my Dec 12 P85 (refurbished A pack). With a SOC of 66% and probably even higher than that. Have not seen this before. I am concerned it is due to battery degradation or other components not performing at initial specs. Waiting for response from service center.
mknox
Well-Known Member
FWIW, I've seen this in my March 2013, A-pack equipped S85 from pretty much Day 1. Floor it, particularly when already at freeway speeds, and see the limit line come up briefly. I am considering it a "normal operating characteristic" unless I hear otherwise. I'd be more concerned if I saw it for the first time now, or even more frequently, but I don't after 2.5 years and over 50,000 miles.
this. it comes on for me sometimes too when flooring it during 'normal' SOC ranges (aka not low).
I recently had a loaner with a VIN in the 57xxx range. I would see a yellow limiter show up at the top of the energy dial while driving on the freeway at 75-80 MPH, not punching it or anything like that. SOC was above 50% for sure, probably closer to 70%-80%. I thought it was interesting. It would appear and disappear intermittently. I have never seen a limiter on my 2013 P85 except for when I ran my range down to zero once.
mknox
Well-Known Member
That does seem a bit off. I've only ever seen it when really punching it, not just when cruising along, even at those speeds.
We know that batteries drop peak performance as they get older. That might explain the issue. I'm not sure I buy the service center explanation. The battery actually performs better when really warm. 40-50 C (104 - 120 F) is best for performance and efficiency. Only when you drive like a hooligan and the temps get over 50 C that's when the old cooling system would have a hard time and performance would be reduced. But that never happens in normal driving! I have been monitoring the battery temperature on my car in all kinds of situations. It's very rare that the temperature goes up to that level.
I don't believe this is true. My 2013 P85 never limits power unless I'm very low on charge. No issues with pack cooling, even when driving from Phoenix to Las Vegas in 120 degree heat!
Olle
Active Member
It's the inverter getting hot, not enough heat conduction between silicone and coolant liquid, no amount of liquid flow will change this in the classic Model S. From my experience driving all versions of Model S I have come to the conclusion that the P85 suffered less from this and classic 60 suffered the most, 85 somewhere between. Theory being that P85 had a beefier inverter that heated up slower and 60 operates at lower voltage (350 V vs 400) meaning more current = more heat.
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