prepping the pack for max power if it's cold soaked
I keep my cars is a garage that doesn't really get below the 50s F.
It's not just about a cold soaked battery, but just a battery that isn't at optimal temperature. From the data we have, the option is for heating the battery to a temperature for optimal performance, and even in warm and sunny CA on a warm day ~80F, it will take a while to hit optimal temperature. Once you launch at optimal temperature several times the cooling will kick in pretty heavily.
So AFAICT from the tests I've done, you will have less than 100% performance, but still in the high 90% performance without the option on, but if you want 100% performance you can either turn it on, or wait for the temperature to rise naturally.
It was 58 degrees in my garage this morning and at 90% I still put out 413KW within 2 minutes of starting out which was the first time I gunned it.
It's clear that at least under these circumstances the 1300 amp fuse is the limit and not the battery's ability to to draw current even when cold. This may change with the 1500 amp fuse and it may be necessary to get the batteries good and warm to reach that fuse's limit but as it stands now, this feature doesn't really seem to do anything all.
Maybe if the pack were close to freezing then it would be another story.
Quick correction. The amperage limit generally won't matter with temperature. It's that the internal resistance drops a little with heat, so A*V = W will yield slightly higher watt output due to the slightly less sagged voltage while the cells are warm. You could still pull 1300/1500A regardless, but the power will be a little different based on temperature.
I honestly am not even sure this increase in power output will be measurable in the performance vs a room temperature pack, though.
In that case, I wonder if the max power mode even makes a difference for the the P90DL at temperatures varying from that of my garage this morning to fully warm. Has anyone with a P90DL logged the max power at SOC X where X is the same for cold in the morning vs max power saying it's ready?
The numbers I logged before were with it on. It was 455 without and 457 with. The 455 was max after several runs, and when I had enabled the mode to get 457 the fans turned on after that run. So as I've mentioned it's just about getting the heat up, which can be done by just launching several times or driving hard. The difference being that launching is going to pull way more power than turning on the heater. If I hadn't launched several times to get the heat up, the first max would have been lower I'm sure.
Honestly at this point it seems like a fairly pointless feature unless there is something we don't know or it is going to turn on some other magic in the future.