Add setting for "Top-down" vs "Bottom-Up"

[dbsb3233]

Currently, ABRP always uses a Bottom-Up charging approach for legs 2+.  Meaning, when you set the min% to 10% and the max to 80%, and it calculates that the next leg will use 53% of the battery, it tells you to charge to just 63% and drive down to 10% (bottom-up).  That makes sense to save charging time if you have a steep charging curve, where it takes a lot longer to charge in that upper part of the curve.  The downside though is that you're always "living on the edge" by running it down to 10% each time, where unexpected headwinds or construction detours or last-minute change of mind can be a real problem.

However some EVs have a fairly flat charge curve, that don't take much longer to charge in the 60-80% SOC area than the 20-40%.  In that case, it's often well worth it to stay at the charger a couple minutes longer each time and just charge up to 80% (that's what I do in my Mach-E since the charge power stays good to 80%).  Much safer, and more flexibility.  So in the example above that uses 53%, it would recommend charging to 80% and driving down to 27% (instead of 63% to 10%).  Top-down instead of bottom-up (like how leg 1 is calculated).

A setting to choose which method we want would be great. 

Edited August 8, 2021 by dbsb3233

[Skyhawk]

I like it.  My e-tron is the same....and in my experience so far we often build in overhead at the stops unintentionally...by the time we're done using the restroom and whatever the car is already to 100% or close.

There is the "charging overhead" field...number of minutes which is kinds-sorta what you're asking for...but minutes instead of SOC.

Piggybacking on the idea, I'd like to be able to change the target to a particular SOC for that particular stop...for example the last stop before destination...I'd like to plan the last stop to say 100% (changeable) so that I have as "much as possible" at the end...rather than having the target set to a least level at the destination

[dbsb3233]

19 hours ago, Skyhawk said:

I like it.  My e-tron is the same....and in my experience so far we often build in overhead at the stops unintentionally...by the time we're done using the restroom and whatever the car is already to 100% or close.

There is the "charging overhead" field...number of minutes which is kinds-sorta what you're asking for...but minutes instead of SOC.

Adding a few minutes to charging overhead might approximate the time it takes to charge a bit higher in the curve, but that's not really the main reason for wanting a Top-Down option.  It's more just to easily see what arrival% will be at each charger when charging up to a set% each time rather than driving down to a set% each rime.  So we know how much buffer we have that leg for detours, unexpected headwinds, last-minute change of plans, etc.

We can always manually calculate it, of course, but the point of a trip planner is to calculate it and display it for us.  I do think that as EVs gradually go more mainstream this decade, more people will want to charge up to a set point rather than drive down to a set point before charging on road trips.  In other words, apply a more ICE-like approach as they're already used to. 

[Skyhawk]

spot on...exactly what I was thinking with my "piggyback idea"...I suppose it's the same thing that you are suggesting.

but for my twist, it needs to be a variable thing for each stop.... not one target for all stops

 

on a multi charge stop trip for example

you might have 1st stop charge to 95%

2nd stop to 84%

3rd stop to 57%

to arrive with 15%

 

but I might want to set the second stop to "at least 95%" because that's my lunch stop and I'll have the time, and set the 3rd stop to lets just say 100% and take whatever I get at the destination...but I want as much as I can get when I arrive

[dbsb3233]

45 minutes ago, Skyhawk said:

but I want as much as I can get when I arrive

That's the key.  Not everyone wants to do it that way, of course.  Some are content playing the traditional "EV game" of only charging the minimum needed to barely make it to the next charger.  That may be fine for the diehards, but most mainstream drivers aren't gonna be comfortable with that.  And with such huge variability in EV mileage based on driving conditions, 10% isn't much buffer to ensure getting to the next charger.  Plus, chargers may not always be working, or not in use. Many people want extra buffer to be able to make it to an alternate just in case. 

It all adds up to taking a few more minutes to charge higher being prudent on DCFC charge #1, then carrying those extra kWh as more safety buffer through the day.

For those wishing to use such a Top-Down approach, the logical set% is wherever there's a significant taper near the upper end (if any).  In the Mach-E, that's easy... it holds DCFC charging power well to 80%, then drops like a rock.  So 80% is the obvious routine DCFC charge-to.  It's probably a different spot in the e-tron.  But we can set that wherever we want in ABRP.

I typically just charge to 80% each leg. I may arrive at the next charger at 27% on one leg, 19% the next, 31% the next, etc.  It would be nice to have ABRP display those arrival% estimates when charging to a set% each time.

Edited August 9, 2021 by dbsb3233

[Sofia-ABRP]

Hi @dbsb3233 and @Skyhawk,

Thank you for your suggestions! I will make sure to forward your ideas.

There are a few features which might help you out in your planning. if you would like to arrive at a charger or the destination with a higher SoC than the default 10% you can edit this in Settings > (detailed) > Battery & Chargers > Destination arrival SoC or Charger arrival SoC. You can also edit the arrival SoC of any individual waypoint. Click the gear symbol next to the waypoint to enter your preference.

You can also add the target SoC for all charging waypoints. Open the waypoint's settings as described above. Toggle the Charge button to "Till" (instead of "For") and type in the SoC of your choice for that unique stop.

Please note that Charging overhead is the time added to each charging stop to account for the time it may take to plug in to the charger, pay for the charging session etc. Charging overhead does not count towards the charging time at a stop, but is added to the driving time of the leg before the charging stop.

/Sofia

[Skyhawk]

very helpful. thanks

I certainly had misunderstood what charging overhead meant!