"Recommend" not going below 20%, yet the Nav wants you to go below 20%..............

"Recommend" not going below 20%, yet the Nav wants you to go below 20%..............

So as is often discussed, what is the ideal SOC range to keep one's battery in. It is general accepted and even battery experts say not to run your battery low, YET, when using the Nav on a trip, it will letting you start your next leg of your trip with an estimated arrival SOC of 10%.

So if it is harmful to the battery to go below say 15-20%, why then does the trip planner have no problem telling you to go that low on every leg of a trip?

I just returned from yet another trip from CT to NC. There were a number of times that the system wanted me to continue on, even though my estimate arrival SOC would be 12%.

lilbean | November 19, 2018

It’s ok.

jordanrichard | November 19, 2018

What's ok?

Bighorn | November 19, 2018

The nav usually lets you know you’re ready to go i.e. stop charging, when arrival SOC is between 8 and 18%. Sure, avoid under 20 with day to day driving at home, but it’s routine with travel. Not to worry.

DTsea | November 19, 2018

except if it is cold or there are headwinds. then carry more buffer. heading west over the cascades out of ellensburg, for example, you need 25-30% due to strong local headwinds.

but that isnt to protect the battery.

jordanrichard | November 19, 2018

Oh, I wasn't really worried, I just found it interesting in the contradiction of advice.

It would be nice if amongst the route instructions they would list any superchargers you may be passing and list them as "Optional". This way if one didn't feel comfortable rolling in at 8%, they could stop for a quick top off at that optional charger. Also, this "optional charger" might line up better for a meal/bathroom break than the suggested stop. I understand they want to plot out the least number of stops, but as I said it would be nice if they also listed the chargers that for some reason disappear from the map.

bishoppeak | November 19, 2018

You don't want to let it sit overnight below 20% or at 100%, but when traveling it's only momentary and harms nothing.

lilbean | November 19, 2018

@jordanrichard What @Bighorn said. I just knew he would explain it. :)

Bighorn | November 19, 2018

I should add that I don’t usually stop charging right when the car says to. I add a safety buffer more for arriving without range anxiety than any concern about the battery.

Bighorn | November 19, 2018

I’ll also look at the route and see if there are intermediate superchargers by highlighting the charger icon. Oftentimes I’ll choose the nearer charger so I can be more efficient and stay out of the slow charging end of the battery. If I can be on my way by 60% SOC, all the better because I’ve managed to avoid much of the taper.

jordanrichard | November 19, 2018

Bighorn, oh I do that too. Though I don't have as many miles under my belt as you, I am not new to roads trips. I typically charge to when it has an arrival SOC of 20%. As I mentioned, it would be nice if they simple incorporated those intermediate SCs along the route.

Anthony J. Parisio | November 19, 2018

bishoppeak +1. I must say I never go much lower than 40%. I can only go about 2 hours before I need the bathroom. Besides I always refill at 50% with my fussil cars. I still do the same now with the Tesla.

Bighorn | November 19, 2018

I just didn't want to mislead any newbs--I know you have it under control:)

Haggy | November 19, 2018

Even letting it sit overnight at 20% won't be a problem. In general, if you stay within recommended ranges, you won't have excessive degradation. That doesn't mean that you necessarily will if you go outside of them. A person who constantly stays below 20% might be at risk. Deciding to charge only when it gets down to 1%, and then charging to 20% so as not to waste an electron before it's needed is a bad idea. So there's a general guideline.

The biggest reason to always stay above 20% is pragmatic. If you get to 20% and charge, you will have more range when you need it. If you get to 20% and don't charge, it will mean starting out at 20% and dropping potentially much lower.

The whole point of the guidelines is that there are an infinite number of scenarios that could take place outside of the guidelines, and Tesla can't cover every single one of them. For example, charging to 100% and leaving on a trip immediately is fine. Charging to 100% and leaving the car for a month, topping off every time it drops to 99% is a bad idea. There are far too many scenarios in between to say which ones will be harmful with an exhaustive list. But there aren't harmful ones between 20% and 90%.

dsodonoghue | November 21, 2018

I frequently charge from low single figures to the high 90s at superchargers - charging is not possible at home and most of my journeys are long ones. I have had minimal degradation - 6 miles - after 3 years and 85k miles. Touch wood!