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Has anyone tested the decline of power on the P3 with the decline in total battery?

AndrewAllen

Member
Mar 19, 2019
211
135
Gilbert, AZ
I perceive to notice a small decline in power starting around 80% of battery left. At 50% it’s more noticeable. Has anyone tested this and if so can you point me to the source? Just curious. Thx.
 

Xevex

Member
Mar 27, 2017
181
197
Canada
I wondered about same thing and without seeing the percentage, I couldn't notice the difference. Probably same in your case too.
 

KenC

Active Member
Sep 4, 2018
3,706
3,363
Maine
Not sure I understand you, but I always thought the power output was lower the lower the state of charge, that's why they charge as much as possible when they go tracking.
 

Watts_Up

Active Member
Mar 4, 2019
3,635
2,452
In a galaxy far, far away
I'm not too much into drag racing but when watching some of them on Youtube, having a top SOC was always mentionned as a must.
Which make sense for a given max current, more voltage would give more power.

However, unless you are in a energy saving turtle mode, I wonder if it's something really noticeable?
 

Adrien

Member
Mar 30, 2016
90
138
Huntington Beach
I would be noticeable. Like you said Volts*Amps= Watts. Current is going to be hard limited at the top end. Voltage is basically the SOC. 4.15V at he top end quickly scaling back to 3.8V or so around 80% and then down from there fairly linearly. An S curve. Do the math and you're down 10% just at 80% and in the lower voltage levels down 25 even 30%. So yeah, to the OP, it should be noticeable.
 

ElectricOrgan

Member
Oct 11, 2019
131
-29
USA
The less battery you have the less power you will have, why is this a surprise?

Capacity and power are two different things. I can fill a 5 gallon bucket from a 1 gal/min tap or fill it from a 5 gal/min tap. Power in batteries is measured in watts, capacity in Ah or Wh which are related by the battery voltage.
 

ElectricOrgan

Member
Oct 11, 2019
131
-29
USA
Not sure I understand you, but I always thought the power output was lower the lower the state of charge, that's why they charge as much as possible when they go tracking.

It is to a small extent, but at the track a small difference matters. The wattage of the battery is the current times the voltage. The current available changes only a bit over most of the charge range, but the voltage changes more. When peak charged the voltage is perhaps 5% higher. The combined effect is noticeable when timing a run.
 
  • Informative
Reactions: KenC

tna9001

Member
Aug 29, 2019
65
35
Asheville NC USA
I’ve just started logging data to answer this question. The first is at 11% SOC the second at 20% SOC. I’ve been too busy the last couple of weeks to get more runs but I’ll post them when I do. Guess I should mention my car is a P3.
2B004366-E95A-41ED-9194-EC394C7DF355.png
7F71BC8C-2BD8-4C96-A777-6085CAD4D3F5.png
 
  • Informative
Reactions: WilliamG

StealthP3D

Well-Known Member
Dec 12, 2018
9,754
77,902
Maple Falls, WA
I perceive to notice a small decline in power starting around 80% of battery left. At 50% it’s more noticeable. Has anyone tested this and if so can you point me to the source? Just curious. Thx.

I have a P3 and there is a barely discernible decline in acceleration at progressively lower charge levels. But it's really subtle because even at 20 % state of charge, the car is ungodly fast and will still take just about any combustion car off the line. By the time it gets down to 10% it's definitely noticeable (although it's still faster than most V-8's).
 

ZOMGVTEK

Member
May 19, 2015
559
434
'Merica
I’d like to see a dyno for an AWD and P3D over various SOC’s. My AWD sure feels slower as it drops below ~85%. By 60% it starts to feel slow. The top end starts to get especially weak below 60 or so, it’s super noticeable if you ask me.
 

Dangerous Fish

Pilots the Millennium Milkfloat
Supporting Member
Jul 21, 2016
1,754
2,827
UK
There's some good information and test results in this thread: P3D+ Acceleration

My experience on track suggess the P3D+ in track mode performs in a very similar way from 90% all the way to 10% at least. Looking at data I logged last time I tracked it, there was very little difference in top speeds at the end of the fastest straight (2-3mph tops) between 80% and 10%.
 

destructure00

Active Member
Mar 2, 2019
1,476
1,629
Scottsdale, AZ
There's some good information and test results in this thread: P3D+ Acceleration

My experience on track suggess the P3D+ in track mode performs in a very similar way from 90% all the way to 10% at least. Looking at data I logged last time I tracked it, there was very little difference in top speeds at the end of the fastest straight (2-3mph tops) between 80% and 10%.


I've noticed significant drop in acceleration at the track below 30%. Below I think about 15% it really falls on its face.
 

Dangerous Fish

Pilots the Millennium Milkfloat
Supporting Member
Jul 21, 2016
1,754
2,827
UK
I've noticed significant drop in acceleration at the track below 30%. Below I think about 15% it really falls on its face.
Have you measured it with a data logger or are you going by feel?
What was the ambient temperature at the time?

I ran mine down to 10% a couple of weeks ago (chasing a F488 around) and the only way I knew I was so low was when I glanced at the display. The data I've got bears me out too.

There must be another difference between your experience and mine rather than just SOC alone.
 

destructure00

Active Member
Mar 2, 2019
1,476
1,629
Scottsdale, AZ
Have you measured it with a data logger or are you going by feel?
What was the ambient temperature at the time?

I ran mine down to 10% a couple of weeks ago (chasing a F488 around) and the only way I knew I was so low was when I glanced at the display. The data I've got bears me out too.

There must be another difference between your experience and mine rather than just SOC alone.

Feel...number of people I pass and the ease at which I pass them. 2 track days with same results. Ambient temp probably around 90. I don't have any data to back it up but I'm 100% confident power is down quite a bit below 20%....30 may be too high. Below 10% the car is a complete dog.
 

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