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My TM Service guy just told me the opposite. Charging up to with range mode and don't use the battery ("letting the car sit") won't do any good to the battery. That's what I'm told by Tesla Switzerland and Tesla Germany (Munich)...

I think there are two different things going on here. Letting the batteries sit at a high state of charge (i.e., full range mode) is bad for the cells. They degrade faster than when they're at at lower SOC. That's why there's range mode in the first place: you're avoiding letting the cells be full much of the time to save their life.

However, being in full range mode charge and letting the car sit for a while allows the batteries to balance, which will increase your range (if you were out of balance to begin with) because of the effect I described in the previous post.

So, what you should do is once in a while charge to full range mode and let it sit. I'd guess a few times per year is sufficient. That will do a small amount of damage to the cells, but balance the battery. The rest of the time, use standard mode charge unless you want to go for a long drive and think you need the extra range.
 
When they say let it "sit" I assume they mean plugged in. This could allow the pack to equalize the cells at very low currents, the lower the currents the more accurate the balancing.
That's hard for me to swallow. Once charging stops ... the charger in the PEM instructs the EVSE to "turn off" and the EVSE opens its contactor so no more current flows. I have not heard of an instance where the charger turns the EVSE back on over a matter of many hours (let's say 6-10). This could only mean ... a) the balancing is an "internal" process within the PEM/ESS; *OR* b) the "stronger bricks" are VERY slowly bled "down to" the weaker bricks, and this indeed takes MANY MANY hours, so that the EVSE getting turned back on much later goes unnoticed due to the length of time (no one having been patient enough with keeping it plugged in).

How about someone in a cool ambient region (Tom / Seattle) and not using the Roadster as their daily driver try this over a two day period ? And if you don't have a TED: charge on HPC, then switch to 120V with a Kill-A-Watt ? :smile:
 
Sometimes I long for the good old days when TMC participated in this site. I don't expect them to be very forthcoming re design considerations, production quotas and the like. But these are the kind of questions that could be answered without compromising corporation sensitive data. In the early days, Martin or JB would have addressed this kind of issue directly. Now, I know we as consumers of that information would never be satisfied, we'd always want more data and would never be satisfied with their attempt to draw a box around what they'd divulge and what they wouldn't. Still, one could hope we could all be sensible. Instead, the easiest way to ensure someone doesn't say something wrong is to say nothing at all. And so it goes.
 
What I don't understand is that balancing should happen during charging and not afterwards. Depending on your charge current the battery has 4 to 20 hours to balance itself. So I don't see the point of "letting it sit".

Lithium cells have a very flat discharge curve. From 10% to 90% the cell voltage changes very little. But at both a low and high state of charge you can see significant voltage changes. The balancing is internal to the pack as the BMS tries to ensure all bricks are at the same voltage. Because the voltage curve is so flat in the mid point of the charge cycle one brick can be at 40% charge level and another at 60% and the voltages are the same. So there is no balancing. But above 90% since the we are now off the flat part of the curve the BMS can see differences between the bricks. As these differences arrise then the BMS can shunt current from the highest brick to the lowest. I just had a discussion with my ranger and he too suggested to charge in range mode and let the car sit to help balance. While I am told the pack can balance in standard charging I also see where it will balance faster in range mode. I plan to give it a try tonight.
 
I just did a road trip where I did two Range mode charges. On the first one I got only 370 km, but on the second one I got 381! And my standard mode charges are now showing higher as well. Not sure how long it will last, but occasional Range mode charges definitely do boost your range.