What should my ideal charge percentage be?

[taraquin]

I'm dense - I think in terms of Amps - I charge at 30 amps when I have all night, and at 40 amps from my home 240 volt 14-50 socket when in a little more of a hurry.
Now you use 12 kW - and I can't relate that to my units. Is there a nice table that shows Amps, kW for different chargers?[ I keep fouling up Ohms law]

It`s a 400V 3-phase (230x3) 16A-charger My voltage is usually 236-242. It`s a European red plug. http://images.biltema.com/PAXToImageService.svc/altimage/xlarge/44-566_xl_1.jpg You live in Arizona? What kind of plugs do you use there? 40A is impossible here, 32A is max With blue plug (1-phase 230V).

 

[AZ Desert Driver]

It`s a 400V 3-phase (230x3) 16A-charger My voltage is usually 236-242. It`s a European red plug. http://images.biltema.com/PAXToImageService.svc/altimage/xlarge/44-566_xl_1.jpg You live in Arizona? What kind of plugs do you use there? 40A is impossible here, 32A is max With blue plug (1-phase 230V).

When I try to deploy Ohms law - 110 volts, 1.4 kw, 12 amps = i find i'm missing Resistance (9.1 ohms back-calculated)
another Level 1 charger = 110 V, 1.8 kw, 15 amp = 7.3 ohm
l2 = 240 v;9.6 kw, 40 amp = 7.3 ohm ( my home charger setup, using a 14-50 plug on 240 volt line.

I can't seem to back calculate a supercharger, or zero in on the Chargepoint chargers that offer power in watts.
I'm a simpleton - need a common unit across my options to weigh them. If it takes me 187 minutes to pump in 30 kw at home, how long does it take when I'm on a Level 2 charger? always seem to be missing an important part of the equation.

 

[scaesare]

I'm dense - I think in terms of Amps - I charge at 30 amps when I have all night, and at 40 amps from my home 240 volt 14-50 socket when in a little more of a hurry.
Now you use 12 kW - and I can't relate that to my units. Is there a nice table that shows Amps, kW for different chargers?[ I keep fouling up Ohms law]

The problem is that without voltage, just using current (amps) doesn't really paint the complete picture.

For instance: like you, at home I have a 40A circuit at 240V. I get a ~28MPH charge rate. At work I also have a 40A circuit, however the voltage often sags under 200V, which only nets me about a 24MPH charge rate.

So the easy equation is voltage X current = power. Your 40A 240V circuit gives you 240x40= 9.6kW power. I'd guess you see a 27-28MPH rate like I do.

Or the easy mental short hand is to just round to "10kW = 30MPH charge rate" and call it a day.

 

[AZ Desert Driver]

The problem is that without voltage, just using current (amps) doesn't really paint the complete picture.

For instance: like you, at home I have a 40A circuit at 240V. I get a ~28MPH charge rate. At work I also have a 40A circuit, however the voltage often sags under 200V, which only nets me about a 24MPH charge rate.

So the easy equation is voltage X current = power. Your 40A 240V circuit gives you 240x40= 9.6kW power. I'd guess you see a 27-28MPH rate like I do.

Or the easy mental short hand is to just round to "10kW = 30MPH charge rate" and call it a day.

Kool- So when I see a Chargepoint tower offering 6.8 kw, I can figure it will be delivering about 20 miles for every hour I'm plugged in, or 10 hours to fill from empty.

 

[whttiger25]

I keep my SOC at 20-50% in summer and 30-70% in Winter. I have a 12 kW-charger at home so I get plenty of juice in a short time when needed. Also a supercharger 45 km away.

I still manage to get 55-56 kWh out of the battery before it says its empty, still the reserve kWs. My car is 3,5 years old now. At a full charge I get 385 km rated and 303 standard range. I believe battery-babycare is the reason However, if I didn`t have a fast charger and SC this Close I would have kept SOC higher.

Why do you keep it so low in summer?

 

[taraquin]

Why do you keep it so low in summer?

With higher temps, degradation rises. Keeping SOC lower in higher temps compensates for that. Below 40% SOC in 20C temp, degradation is viritially non-excistent. Since I have fast charging options at home and SC close I prefer battery babycare. Matters more for me with my S60 than for those with 70kW+

 

[robby]

With higher temps, degradation rises. Keeping SOC lower in higher temps compensates for that. Below 40% SOC in 20C temp, degradation is viritially non-excistent. Since I have fast charging options at home and SC close I prefer battery babycare. Matters more for me with my S60 than for those with 70kW+

Isn't this backwards? More heat is generated at lower SOC while driving, because as voltage drops, more amps are needed to provide a given power. Or are you saying that there is something about the battery chemistry that it is more tolerant of heat at a lower SOC?

 

[Snowstorm]

I am awaiting my level 2 install at home now so I have to charge 90% during the weekend to make it though the week. Once I is installed, I would expect to fall back to something like 60-70%.

I use li-ion batteries on my model aircrafts and pretty much only store them at 40-50% charge level. I do charge them to 100% frequently, but would use them within a few hous. I kind of see it like a balloon, don't want to keep it fully inflated for too long or it will get loose.

 

[TexasEV]

I am awaiting my level 2 install at home now so I have to charge 90% during the weekend to make it though the week. Once I is installed, I would expect to fall back to something like 60-70%.

I use li-ion batteries on my model aircrafts and pretty much only store them at 40-50% charge level. I do charge them to 100% frequently, but would use them within a few hous. I kind of see it like a balloon, don't want to keep it fully inflated for too long or it will get loose.

Your model aircraft don't have Tesla's battery management system.

 

[alehbaba]

so in colorado with s60d new...what should i set it to? 80%??

 

[msnow]

so in colorado with s60d new...what should i set it to? 80%??

70 - 90, whatever works best for your daily driving needs. There's no magic number.

 

[Vern Padgett]

I just finished reading all 22 screens. Jeez. I'm going out to reset my max charge from 80 to 90 percent. Wife will be driving it within a few hours of that charge.

What I did not learn from all 22 screens was the point of keeping the connecting cord plugged in whether or not one is charging. What is the point of that?

 

[Snowstorm]

I just finished reading all 22 screens. Jeez. I'm going out to reset my max charge from 80 to 90 percent. Wife will be driving it within a few hours of that charge.

What I did not learn from all 22 screens was the point of keeping the connecting cord plugged in whether or not one is charging. What is the point of that?

The car use some power to keep the battery conditioned, run the LTE connection etc. If you keep it plugged in, it will use the plug power. If you don't, it will pull from the 12v battery, which needs to be recharged by the main one. Only a bit of charge is lost, but it does shorten the live of your 12v which I have heard will need replacement once every couple of years

 

[tnt1971]

What I did not learn from all 22 screens was the point of keeping the connecting cord plugged in whether or not one is charging. What is the point of that?

I disagree slightly with the previous answer. The only time the car draws power from the line, and you can tell because of the "chase" lights on the charger, is when it is charging or if the climate control is on. If it is plugged in and not charging, you will still see the vampire drain of 3-5 miles a day, and more if it is really cold.

The point of plugging it in is if the charge drops below the set target by a certain amount (I have heard 5%) it will automatically charge back up to that target. If you have the timer set in the charge screen it will check it at that time every day. I don't know if/when it checks if the timer is not set.

I have left my car twice now for more than a week while away. In a garage where the ambient temperature does not fluctuate much, it is pretty predictable how much charge it will lose, and you can plan accordingly.

 

[msnow]

I disagree slightly with the previous answer. The only time the car draws power from the line, and you can tell because of the "chase" lights on the charger, is when it is charging or if the climate control is on. If it is plugged in and not charging, you will still see the vampire drain of 3-5 miles a day, and more if it is really cold.

The point of plugging it in is if the charge drops below the set target by a certain amount (I have heard 5%) it will automatically charge back up to that target. If you have the timer set in the charge screen it will check it at that time every day. I don't know if/when it checks if the timer is not set.

I have left my car twice now for more than a week while away. In a garage where the ambient temperature does not fluctuate much, it is pretty predictable how much charge it will lose, and you can plan accordingly.

No, not correct. The previous answer was correct.

 

[Vern Padgett]

I guess I'm still not getting it-- I should draw electricity at 48c per kWh during peak load times in case the main battery drops below a set target-- one that it has never approached within 20 or 30% of since we've had the cars? This advice (keeping it plugged in) is for people who go on vacation for weeks and months, right?-- not for everyday drivers who charge to 80 or 90% in the middle of the night at lowest cost, once the battery is down to 20 or 30%?

 

[msnow]

I guess I'm still not getting it-- I should draw electricity at 48c per kWh during peak load times in case the main battery drops below a set target-- one that it has never approached within 20 or 30% of since we've had the cars? This advice (keeping it plugged in) is for people who go on vacation for weeks and months, right?-- not for everyday drivers who charge to 80 or 90% in the middle of the night at lowest cost, once the battery is down to 20 or 30%?

If your battery is plugged in the car will pull from your wall connector for the housekeeping current it needs to function. These are not high voltage requirements like charging your battery is so you don't need to worry about TOU or peak hour limitations. If it's not plugged in, it will pull from your 12v battery which puts unnecessary strain on that battery. That's why Tesla recommends to "always keep your car plugged in".

 

[tnt1971]

No, not correct. The previous answer was correct.

It has not been my experience. I charge my car at work and I set the timer so that it finishes about the time I am getting ready to leave. I plug it in in the morning and it sits for roughly 8-10 hours before it starts charging. During that time, it usually loses a mile or two before the charging begins, so I don't think it is drawing from the AC current. Admittedly, I do not have a watt meter on the plug to tell.

 

[msnow]

It has not been my experience. I charge my car at work and I set the timer so that it finishes about the time I am getting ready to leave. I plug it in in the morning and it sits for roughly 8-10 hours before it starts charging. During that time, it usually loses a mile or two before the charging begins, so I don't think it is drawing from the AC current. Admittedly, I do not have a watt meter on the plug to tell.

Ask Tesla. Also, if you search this forum you will find plenty of examples of people who didn't and had to pay to get a new 12v battery which wasn't covered under the warranty.

 

[jerry33]

This advice (keeping it plugged in) is for people who go on vacation for weeks and months, right?-- not for everyday drivers who charge to 80 or 90% in the middle of the night at lowest cost, once the battery is down to 20 or 30%?

Not correct. The smaller the cycles, the longer the battery will last. If you are going for several weeks or months, then set the slider to 50%. For normal use plug in every day. It appears from the posts in this forum that 90% with the occasional 95% charge to engage the charging circuits (they engage at 93%) gives the most life.

The way it works is that if you charge from 0 to 100 all the time, you'll get somewhere around 300 cycles (this number subject to correction, but it's not very many). As the amount of daily charge decreases as a percentage of the battery the number of charges goes way up--not linear, but exponentially. So you should plug it in whenever possible to maximize battery life.