# Question About Supercharging On Road Trips



## Brjm40 (Jun 9, 2020)

Hi Folks, old guy and new EV owner here. When road tripping I usually charge up to something like 70-80%. Does setting or leaving the charging limiter bar to 100% rather than 70-80% help the car charge faster and with less tapper? Thanks for your help. Brian


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## FRC (Aug 4, 2018)

No, the taper occurs relative to 100% capacity irrespective of the fill limit you have selected. Charge speeds are best in the bottom half of the battery, so generally your best bet is to charge only enough to get you(comfortably) to your next charging solution.


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## garsh (Apr 4, 2016)

Given ideal environmental conditions, a Model 3 will supercharge at high speeds up to about 50% capacity. Speeds will keep tapering down above that, regardless of the limit you have set.


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## potatoee (Aug 26, 2018)

I've had my M3 LR for about two years. I've since relaxed quite a bit as to how I do long trips and don't overplan things since I usually find that despite my plans, things change anyway (e.g. having to make a potty stop and charging earlier than anticipated for convenience purposes, more consumption due to excessive A/C or heating needs, etc.). In short, I've adopted two simple habits:

1) Charge to 100% at home prior to leaving. Charging at home takes longer and all charging takes longer towards higher SOC (state of charge). I time this to coincide with my departure time since I like to keep my batter happy (I'm needlessly obsessive about this ;-))
2) On the road, I use the SC network and tend to charge until I have enough juice to make my destination or to until I notice a charge taper (somewhere around 70% is when I first notice it, may be slight at 50% as mentioned above). Depending on the tapering and where my next charging opportunity is, I charge more or less.
3) If my final destination or evening destination has a charging resources, I factor this in to arrive with a lower SOC (down to 10% or less depending on my mood). I leverage what might be free or cheaper charging in the evening to bring the charge up to whatever my goal is. Note that since I'm doing something else by the time I'm there, I don't care about the charging rate.

Keep in mind that the tapering is a gradual curve. The tapering is very small at first and becomes very obvious as you approach 100%. Take into account the situation of the moment to determine how much you want to wait to get more charge. Don't worry about the car. Do what's convenient for you. You won't ever get stuck if you use your nav appropriately and are aware of your charging options.

Hope this helps. Enjoy!


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## FRC (Aug 4, 2018)

One more point. Never, and I mean never, leave your current charge until you are absolutely positive that you can make it to your next charge(or an earlier plan B back-up charge). Even if you could have made it, a few extra minutes charging is well worth it to avoid the angst of running too close.


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## potatoee (Aug 26, 2018)

FRC said:


> One more point. Never, and I mean never, leave your current charge until you are absolutely positive that you can make it to your next charge(or an earlier plan B back-up charge). Even if you could have made it, a few extra minutes charging is well worth it to avoid the angst of running too close.


Very true. In my newbie days, on one trip on a particularly warm day (90+), I realized after heading off from one SC that I didn't have sufficient charge to make it to my destination. Not a big deal but I had to make an additional stop at the next SC to make it. I only realized this 15min after I left.


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## NR4P (Jul 14, 2018)

I do a few 450 mi each way trips periodically.

The Nav system is a great tool to tell you ideal stops. Even if you know the route, put in the destination and the nav system is very helpful. Prediction of charging time in mins is reasonable but can be slower if the car next to you is charging. It usually tries to have you stop for a charge around 20%, assuming there is a supercharger around that. At 20% or 30% assuming no car in the next spot at V2 charger, it charges at max rate. But if I stop at say 55% charge, the rate may be 80KW.

Even when I follow the NAV systems directions I never see it pre-condition with the on screen messasge. But if I change to a different supercharger that it didn't navigate too and change the Navigation route, say 10 miles before the next supercharger, it will start pre-conditioning with on screen message.

One caution, it attempts to have you arrival at final destination around 20% or so. Think about that, are their destination or L2 chargers there? Or a 24hr L1 charger? Or superchargers to return home? So don't leave yourself with too little charge to get to your next destination unless you know charging at arrival or close by is ok.


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## FRC (Aug 4, 2018)

Great point about the %charge at arrival. I think this is often overlooked by newbies. The car's NAV system will get you to your destination, but it might not let you leave!


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## Garlan Garner (May 24, 2016)

I have not found an advantage to charging to 100% before I left for a trip. 

It could possibly get allow you to skip an initial SC, however I have found my best charge times when I arrive at a SC with 10% battery left. - while at the same time making sure I arrive at the next one with the 10% battery left.


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