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Description:  When calculating a route I think it would be useful to have the option to select a max percentage for a DC fast charge session unless it was impossible to get to another charger with less. Settings currently has "start depart charge %", "charger arrival charge %" and "goal arrival charge %" but I would really like an option to set a "charger maximum charge %" which could be overridden if required.

As we all know, charge rates drop quite considerably as the battery capacity nears completion, this increases time and cost (on time based charging) for a charging session as the battery gets closer to its maximum capacity, so I feel it could be advantageous to finish a charge session earlier but make another charge stop to top up to be able to complete the journey.

Here in New Zealand it is generally frowned upon if you use a DC fast charger to charge your car above 80%, and the Tritium Veefil chargers which are popular here automatically select 80% before charge starts and you need to override if you want to charge past 80%. As the charge rate over 80% is actually quite low, it is not only slower but it's also more expensive to charge above this figure than it would be to add an extra charge session to the journey. I understand at times that a journey would not be able to be completed as the distance between chargers is too great, but this is the only situation I would like to charge to a higher level.


Use Case: When planning a route I would like to be able to set my maximum DC fast charge percentage to 80% (or possibly lower) so it will automatically route me via more chargers for shorter/more efficient charge sessions instead of having some charge sessions go over 80% but pass other chargers on the route which you don't use. I currently have planned routes that take individual charge sessions over 90%, which I know in my 60aH BMW i3 will take longer to complete than the planner is suggesting, and will cost more as we are charged 25c/kWh + 25c/minute. Automatically planning more charge sessions would make my journey planning easier as currently I am editing them to work under these rules.

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In a sense we already do this by optimizing the route for time.  We already check to see if one charger or another is faster, or if it's faster to charge less on this charger and more at the next one.  Can you post an example route where detouring to a second charger decreases travel time vs charging to 90%?

It sounds like the root cause of the problem is an inaccurate charge curve for the BMW i3.  At the moment, since we have no way to pull live data from the i3, we're stuck with just what's been reported to us and what's publicly available online.

If you can record some real-world charging performance (take a video of your dash while charging, recording power output and SoC) that would help refine the data and improve our planning estimates.

Alternately, the best thing would be to figure out how to pull data from the i3, we'd need to work with someone tech savvy and with access to an i3 to decode the OBD interface.  It's certainly possible as there are apps out there which provide that information.

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On the i3, it should be noted that the 120Ah version maintains a high rate of charge until approximately 90%. So if something like this is implemented it'd probably need to be tailored for each different version of the i3 (and other cars too).

I think it would be good to have the option to set the max. % of each session on a charger-by-charger basis (i.e. through the pop-up menu that appears when a charger is selected on the map). I think this would be a good way of doing it because at a charger with several stalls you may be more comfortable allowing the max % to reach >80 or even >90 %. At a charger with just one stall you may want to limit it strictly to no more than 80% to avoid annoying other fellow EV drivers.

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