On Facebook one of the recently replaced 21.5 batteries showed some differences in the side plates and the bottom cover. Could be related to heat management. Just speculation at this point.
The yellow icon shows when max battery temp reaches 41 degrees Celsius.
Charge speed drops around 36 degrees Celsius. This graph shows the relation
Worst I've seen is 7 kW charging after around 700 km riding. In summer (typically 20 to 30 degrees ambient) the problem is that the battery keeps building up heat because in between charges it doesn't get to cool down enough. For summer the only solution so far is to ride as long as possible between charges. That translates to no highway to maximize range, but in the end isn't faster because of the lower average speed.
In winter time (typically -5 to 5 degrees ambient) it does drop in between charges and I can keep riding and charging. Only done that for 400 km a day so far. When I travel I try to stay around 400 km a day anyway. Especially when you ride day after day that is already quite a distance.
System keeps track of min and max temp. Max temp is what is monitored here. I had a blue icon once but forgot to check the min temp at that time. It's below 10 degrees Celsius for sure. And I rarely see it because the bike is parked inside and once you ride the battery heats up. On highways you get a nice 25 degrees operating temp even when it's only 5 degrees ambient.
They've extended the liquid cooling from the inverter to the motor recently. If they would do that to the battery we're golden. I would personally prefer that over extra capacity in the next developments. If the heat is managed we should in theory also be able to use more of the capacity anyway. So we might get both
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