Reducing battery drain on the track

[play150]

How quickly is the battery draining for y'all when doing HDPE? The last time I went there was one 20 min session when I lost 20%! (I may have been going too ham though lol) Thankfully there's a (single) 50A outlet at the track to charge with, but it definitely isn't fast enough to keep me eventually reaching close to 0%. The nearest supercharger is like 40 mins away unfortunately.

Wondering if I should go in chill mode so that I dont have to skip 1-2 sessions in the day to charge, though I saw someone here mention that it didn't reduce battery draw that much on the track.

 

[Lindenwood]

If I were doing an HPDE tomorrow, I’d use Chill Mode for the first session to force myself to focus on the lines and conserve battery.

My local track is relatively tight, but my last event I was using about 2% per minute in Track mode, but only about 0.5% per minute in Chill Mode. Interestingly, despite using 400% of the energy in Track Mode, my lap times only dropped by around 2-3%.

 

[Arthur31]

So at LimeRock (which has about 15 L2 chargers) I would do a 20 minute session (in the instructor group so the pace is fairly rapid) I would go from 100% in the morning and roll off the track with about 60ish % remaining. Go right to the L2 and plug in and I would be at mid 90% charge about 2 hours later. Rinse and repeat for the rest of the day, I was able to do 4 sessions.
At Pocono infield it was basically the same as LR, they don't have L2 chargers but they do have 14-50 outlets in the NASCAR garages so same basically.
These are both "small" tracks and I was quite happy with how it all went
Now at Watkins Glen I would easily get down to 40ish % after 20 minutes ( power loss was noticeable but nothing crazy) and they only have RV hookups that provide 32 A so would skip the next session (of 4) and be ready for after lunch to run the next 2 sessions. I would cut the 1st after lunch session short by about 5 minutes so I could get back on the plug and be ready for the last session with about 90% charge.
I did 6 events this year and I was very happy with how the car dealt with everything.

 

[Mash]

I really dont understand the point of slow driving on the track. I use 80% in 15 minutes time with a cool down lap in the middle. Whats the point of going slow on the track?

 

[ngng]

I really dont understand the point of slow driving on the track. I use 80% in 15 minutes time with a cool down lap in the middle. Whats the point of going slow on the track?

Most people who I’m riding right seat with, especially high power cars, benefit from slowing down

 

[Arthur31]

full attack ( with respect for other drivers) from the moment I leave the pits every time. I’ve been racing / instructing for 20+ years.
But I must say why would you care if someone isn’t giving it 100% each lap?

 

[Mash]

full attack ( with respect for other drivers) from the moment I leave the pits every time. I’ve been racing / instructing for 20+ years.
But I must say why would you care if someone isn’t giving it 100% each lap?

Either I'm doing something wrong or im unaware of what else can be done on the track. Its a vast power consumption difference. I am using excessive braking, because I dont have enough seat time, but that or track difference can't explain 4x power consumption difference to me. Nurburgring BTG of 7:40 from pro driver took 65% of battery.

So whats the secret?

 

[Arthur31]

Either I'm doing something wrong or im unaware of what else can be done on the track. Its a vast power consumption difference. I am using excessive braking, because I dont have enough seat time, but that or track difference can't explain 4x power consumption difference to me. Nurburgring BTG of 7:40 from pro driver took 65% of battery.

So whats the secret?

No secret. Just have fun and if you feel that using all your battery per session is better then rip it up.

 

[gearchruncher]

I use 80% in 15 minutes time with a cool down lap in the middle.

Dang. This is 65kWh in 15 minutes, which is 240kW average, which is 320 HP. Being able to average 320 HP of output for 15 minutes solid is not something that can be done on every track, especially with a slow lap in the middle. Spend 25% of your time braking or in a corner, and suddenly you need to be doing 430HP average every time you are on the power, which a M3P can barely do.

Nurburgring BTG of 7:40 from pro driver took 65% of battery.

This isn't super logical. This would require ~380kW of draw, which is 510HP. The Model 3 cannot sustain 510HP, period, and especially not at high speeds or lower SoC's when the power falls off.

 

[Mash]

Dang. This is 65kWh in 15 minutes, which is 240kW average, which is 320 HP. Being able to average 320 HP of output for 15 minutes solid is not something that can be done on every track, especially with a slow lap in the middle. Spend 25% of your time braking or in a corner, and suddenly you need to be doing 430HP average every time you are on the power, which a M3P can barely do.


This isn't super logical. This would require ~380kW of draw, which is 510HP. The Model 3 cannot sustain 510HP, period, and especially not at high speeds or lower SoC's when the power falls off.

I might be 5-10% off, but it's the case otherwise. You are not calculating loss at high power use.

 

[MasterC17]

At full power a modified Model 3 with a good driver will consume about 20-25% every five minutes. Of course, it can only keep this up for 7-10 minutes before hitting significant power limiting.

In the Model 3 Challenge, we limit the cars to ~220kW to preserve energy and extend runtime. In a 15 minute race, the car consumes about 50%-55%, but without noticeable power loss.

 

[wzj998]

A feasible approach is to refrain from fully depressing the accelerator after each turn (even consider using a throttle controller), and instead, focus on pushing the vehicle to its limits during corner entry and mid-turn. However, if you aim for optimal lap times, this strategy might not be meaningful. Based on my personal experience on a small track approximately 2km in length, a full-throttle lap at maximum acceleration consumes around 4% to 5% of battery capacity.
Also, can anyone tell me the impact of regen on battery drain on the track?

 

[subieworx]

I've probably driven more tracks that most have in mine and generally see a 30-35% reduction from 100% starting in 4 laps (1 warm up very easy, 2 hot, 1 cooldown). Obviously this varies based on the track and amount of throttle usage. Highest I have seen is at watkins glen.

For those plugging into RV outlets at the track, get yourself a Tesla wall L2 charger and wire it to work on an extension cord. Will get you 48a instead of 32a max.

 

[buckets0fun]

For those plugging into RV outlets at the track, get yourself a Tesla wall L2 charger and wire it to work on an extension cord. Will get you 48a instead of 32a max.

Please don’t run 48a on a 14-50 NEMA socket with a 50a breaker.

 

[gearchruncher]

For those plugging into RV outlets at the track, get yourself a Tesla wall L2 charger and wire it to work on an extension cord. Will get you 48a instead of 32a max.

Second time I have seen you out in the world telling people to violate the national electric code. Let's not do this as racers. We already have tracks not allowing EV's at all due to theoretical fire risk out on track, let's not prove them right by messing up their electric setup.

The correct answer is a Gen 1 UMC which will do 40A legally off a 50A socket, or many of the 3rd party J1772 cords that will do 40A.