State of Charge When Arriving at Charging Station

[YeOldeTraveller]

The reason planning to arrive at a charging station with such a low state of charge is for contingencies like an inoperative charging station. I would want some range to move on or backtrack to one that works.

For planning, I target a 15% arrival. While driving, I don't worry about arrival state of charge until it drops below 10%. At that point, I may reduce speed depending on how far I am from the planned charge stop. I don't get concerned until 5%, and that is the level where I will take more drastic measure, but only if I am not already close to the charger. If the destination is home, I only worry about arriving above 0%, but I will have slowed down somewhat under 10%.

It is also good to know options short of the planned stop if you find that you are getting worse efficiency than planned. This gives you a bailout point where you can stop for a short charge to recover buffer.

A note on planning:
On routes I don't know well, I start with ABRP, and check the stops it plans. I think look at each stop to see who runs that site, and what alternatives are close. Depending on reliability and options, I will add additional buffer for that leg if I feel the need. If there are reliable options within 10 miles, I don't bother with an adjustment. I use PlugShare to research the planned stops, and those nearby to get an idea of what I need for contingency.

Personal note:
I have always planned my road trips, so the level of planning I do for an EV road trip is hardly more that before. One needs to know where the chargers are as you do need to know where you are going to start earlier than road signs are going to tell you.

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[phidauex]

Most range anxiety is just that - anxiety. When I first got the car in 2021 I would leave much larger destination buffers because I just didn't know the car as well. Now after 50k miles and many road trips, I know my usage very precisely, and I don't mind pulling into chargers at 2-5% SOC, especially in cities where I know there is more than one DCFC (so if there is a last minute problem at one charger, I know I have another a few miles away).

It is OK to be conservative at first, but most people get used to it the same way they got used to when they needed to stop to fill up their ICE vehicles (they had to learn that at some point in the past, too).

I don't know where this "bad for the battery" business on low SOCs is coming from - NMC and LFP batteries are both fine with low SOCs. They don't want to hit a chemical 0%, but Ford holds back the bottom ~4% so that you can never even get close to a real 0%. But the battery won't suffer additional degradation by using down to low SOCs when you need to. NMC and LFP batteries do suffer slightly higher degradation at high SOCs (the difference between NMC and LFP here is overstated), but again, Ford holds back the top several percent as a buffer. I charge to 100% when I need to, but mostly leave it at 80%.

I'm at 92.5% SOH after 4 years and 50k miles, including a fair amount of DCFC (about 20% of my miles is road trip), trips in extremely low temps and extremely high temps, stored outdoors.

 

[Snakebitten]

Most range anxiety is just that - anxiety.



I don't know where this "bad for the battery" business on low SOCs is coming from.....

Early EV chemistry and battery thermal management, or lack thereof?

Had a depreciated 2nd hand Nissan Leaf, for dipping my tows in the EV waters with low risk. Learned a LOT!

The Mach-E is far more sophisticated battery and thermal management. I rarely even check its SOH these days. With the Leaf, you would monitor it perpetually.

 

[ex2bot]

I second the people recommending charging at 10-15% unless a break is needed. New EV drivers might want to charge at 20% until they’re used to everything.

I don’t typically go much lower than 10%. Some vehicles go into turtle mode at 5% or even higher. Worse, if the BMS is off (rare), a car might die before 0%.

 

[dan_meh]

New EV drivers might want to charge at 20% until they’re used to everything.

Agreed. On my first trip, I started sweating at 50%. And I think that’s the OP’s point. A friend is new to EVs and was uncomfortable going to single digit percentage. I was too. I still am, really.

I don’t know the Tesla route mapping, but maybe it’s set up for high risk tolerance or veteran road trippers?

The Ford nav has its problems (lord knows I gripe), but it correctly understands that the defaults should be set at 15-20% arrival state of charge. Given the choice between scaring new EV drivers and arriving “further into the curve,” Ford chose wisely.

Next generation system, however, should default to 15-20 and let drivers change it.

 

[SonicBlue]

I never go below the percentage that could still get me to a DCFC Plan B. Not sure if routing software is sophisticated enough to consider that?

 

[Cuddlecool]

My ChargePoint HomeFlex was a welcome sight when I pulled into my garage tonight. I left the house this morning with about 50% SOC and maybe 120 miles on the GOM. It’s been cold here in Texas this week, with overnight lows in the 30s, and a good portion of my travels around Austin today were at 80+ mph on TX45 and TX130. But I love living on the edge.

 

[ChasingCoral]

For best battery longevity as well don’t let it get below ~25 to 20 % soc (state of charge). Going above 80% as well is extremely harsh on the battery

This is like most conspiracy theories: a bit that is true and a lot that is wrong.

You don’t want to have the battery SIT near zero or 100%. However, it is fine to use the full battery range.

Feel free to drive to a few % SOC, then plug in to charge.

Similarly, if you are going on a long trip, you can AC charge to 100% the night before you leave.

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