Remove the 25% minimum charge

[whitex]

10%battery is enough energy to pre heat my car AND get home but my Taycan won’t preheat if it’s below 25%.

SoC is an estimate. Once you get under 10%, you're not really guaranteed the full 10%, it might die on you at 1% or start dropping a lot faster than expected. Furthermore, the car doesn't know how long you're going to park it, or how cold it's going to get. Park it in a windy parking lot with sub zero temperatures, and you may use the entire 10% to just preheat the car. One problem with lithium batteries, they die when discharged too low, and also don't like being stored under 20% SoC, hence manufacturers will try to strongly encourage something like 25%+ when parked, if possible. Yes, there is a anti-brick buffer, which will preserve the battery, but you will need a jump start to start a car in such self-preservation mode as it stops maintaining the 12V battery. Also, if you freeze a battery at low SoC, it will take a very long time to charge back up even at DC chargers - this happened recently in Chicago, causing a whole lot of anti-EV media coverage how EV's don't work well in the cold - one example was a guy who let his EV down to 3%, then the car took hours to recover at a DC charger because the battery was frozen while he was parked waiting for his turn, and frozen battery at 3% dropped to 1% and was only not able to accept a charge, had to preheat from shore power first for a couple of hours.

Bottom line is that it's easier to push everyone to stay above 25% when possible, than have to deal with explaining complex issues that arise at low SoC usage. It's generally better for the end user experience, and better for the battery longevity (hence better for the manufacturer who has to warranty it).

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[Ross]

SoC is an estimate. Once you get under 10%, you're not really guaranteed the full 10%, it might die on you at 1% or start dropping a lot faster than expected. Furthermore, the car doesn't know how long you're going to park it, or how cold it's going to get. Park it in a windy parking lot with sub zero temperatures, and you may use the entire 10% to just preheat the car. One problem with lithium batteries, they die when discharged too low, and also don't like being stored under 20% SoC, hence manufacturers will try to strongly encourage something like 25%+ when parked, if possible. Yes, there is a anti-brick buffer, which will preserve the battery, but you will need a jump start to start a car in such self-preservation mode as it stops maintaining the 12V battery. Also, if you freeze a battery at low SoC, it will take a very long time to charge back up even at DC chargers - this happened recently in Chicago, causing a whole lot of anti-EV media coverage how EV's don't work well in the cold - one example was a guy who let his EV down to 3%, then the car took hours to recover at a DC charger because the battery was frozen while he was parked waiting for his turn, and frozen battery at 3% dropped to 1% and was only not able to accept a charge, had to preheat from shore power first for a couple of hours.

Bottom line is that it's easier to push everyone to stay above 25% when possible, than have to deal with explaining complex issues that arise at low SoC usage. It's generally better for the end user experience, and better for the battery longevity (hence better for the manufacturer who has to warranty it).

All good science that and totally agree.
It’s just that if it’s cold I want to heat up before spending 15 minutes driving 2.8 miles home. It is the mild UK so -5C would be the worst. I rarely am at low charge but 10% is guaranteed enough to heat up my car and get home if I happen to be that low.
Just annoying I can’t do it.

 

[whitex]

All good science that and totally agree.
It’s just that if it’s cold I want to heat up before spending 15 minutes driving 2.8 miles home. It is the mild UK so -5C would be the worst. I rarely am at low charge but 10% is guaranteed enough to heat up my car and get home if I happen to be that low.
Just annoying I can’t do it.

I get it's annoying. You might have a good understanding and knowledge of weather, parking conditions, how long you will park, etc. However, as a generic solution it's just easier for Porsche and other manufacturers not to have to deal with people who overestimate their battery capacity, or don't understand the low SoC issues.

PS> If you really want to prevent charging outside of cheap electricity window, you can get an EVSE with timers, and let that EVSE manage charging. On the Taycan, just set a profile to minimum whatever your target is, and the EVSE will only allow charging during set time windows, while the Taycan will limit the maximum via the profile minimum (I know, Porsche charging UI is horrible).

 

[Dave Birch]

That bit I know. I was just wondering how you ended up with a 12hr window.

I suspect I use too much generally

Octopus calculated that to be at 85% tomorrow by 0530 12 hr was needed. If I had been at a fuller state of charge it would start charging on plug in, pause for hours and then start. It’s a clever little bugger.

 

[bn8959]

Octopus calculated that to be at 85% tomorrow by 0530 12 hr was needed. If I had been at a fuller state of charge it would start charging on plug in, pause for hours and then start. It’s a clever little bugger.

This is why I like to set the integration with the EVSE rather than we car. When you do it this way, you select in the Octopus app what percentage you want to add. Just leave it at 100%. Then whenever you plug in Octopus will try and schedule you a big long window at the cheap rate. There isn’t a way for it to know your current SoC so it can only assume you want to add the full 80+ kWh. I’ve plugged in at midday before and had low rate scheduled from midday to 4pm then 8pm right the way through to 8am the next morning.

I then just use a profile to limit the charge level to 85% in the car.

 

[Dave Birch]

This is why I like to set the integration with the EVSE rather than we car. When you do it this way, you select in the Octopus app what percentage you want to add. Just leave it at 100%. Then whenever you plug in Octopus will try and schedule you a big long window at the cheap rate. There isn’t a way for it to know your current SoC so it can only assume you want to add the full 80+ kWh. I’ve plugged in at midday before and had low rate scheduled from midday to 4pm then 8pm right the way through to 8am the next morning.

I then just use a profile to limit the charge level to 85% in the car.

Smart idea.

 

[DrRach]

This maybe an unpopular opinion but you’re driving on average £100k car and you worrying about 15% charges at 30/kw.
If that’s all I had to worry I’d be a very very happy man.

For us, we like it, simply because if we arrive home at 10% at 5.30pm and we need or want to nip out in the evening, It will go into limp mode at I think approximately 5%, it would ensures when she needs the car it has enough charge to enjoy it fully.

My wife loves the car and I’m waiting on the new 911 GTS to be released.

 

[RTH]

Has anyone figured out how to use charging profiles but get rid of the 25% minimum charge?

The reason I ask - I arrive home at 9pm, I have about 10% battery left. I want to plug in my car and relax, however my car will then charge to 25% straight away and then it stops and then charges overnight. However I am then not using my cheap rate of 7.5p but 29p to get up to 25%.

I have a wall charger, but I don't want to be messing around with timers on here as we have more than one EV (the other is setup on Intelligent Octopus which manages the charge times).

It is not a big deal, but it does mildly annoy me.

Thanks

I used an Enel X charger that sets its own preferable charging time. That way, even if the Taycan wants to charge, there is no "juice" to charge.

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