Pre-heating, connected to charger all night or not?

[gorjan]

Hello,
I have a question related to pre-heating. We have a 2017 model with wifi and electric heater. I have configured the wifi/app and it´s great to turn on pre-heating so we can go out to a warm car now as winter is closing in. Reading all the different threads concerning battery wear made me think. Usually, we connect the charger when we get home and the car is usually fully charged before we go to bed.

Is it best to disconnect the charger, and then connect it again in the morning, just before starting pre-heating from the app? Or is it best to keep the car connected to the charger over night? What will do the least/most damage to the battery? Thank you for your input.

 

[Daff]

Leaving the charger plugged in overnight shouldn't cause damage. The car stops drawing mains power when it's full (and presumably starts drawing power again when the preheat starts, although I haven't got around to trying that yet.

Steve

 

[gorjan]

I thought this would be the best option. As I understand "top-up" charging should be avoided, and disconnecting/connecting the charger seems to result in a short charge. Thank you.

 

[anko]

I thought this would be the best option. As I understand "top-up" charging should be avoided, and disconnecting/connecting the charger seems to result in a short charge. Thank you.

Indeed you can here the car clicking about when reinserting the plug. The charger / charge cord will go into "charging" state. Whether the car actually draws power and whether that power is actually fed into the battery, I have never checked. Either way, you could prevent this by leaving the plug inserted or by inserting the plug only after pre-heating has started.

I think it is more important to look at the end of the pre-heating process. If you let the car sit there plugged in after the pre heating has finished, then the battery will get a top up.

 

[gorjan]

So it match be better to start 20 min pre-heating and go out tic the car after around 15-19 mins, disconnect charger and drive off? Also I don’t understand what the *-symbol is? Is that only relevant to cooling/AC during the summer? Because it seems to warm up to my desired temperature now, and turning on/off the * doesn’t seem to do anything with regards to temperature or range.

 

[geoffshep69]

So it match be better to start 20 min pre-heating and go out tic the car after around 15-19 mins, disconnect charger and drive off? Also I don’t understand what the *-symbol is? Is that only relevant to cooling/AC during the summer? Because it seems to warm up to my desired temperature now, and turning on/off the * doesn’t seem to do anything with regards to temperature or range.

The snowflake symbol turns the Air Conditioning on and off. This is separate from the temperature setting, but obviously if you want cool air in the summer then you need to have the A/C switched on, and if you want dehumidified heat in the winter (to reduce the amount of moisture / fogging in the cabin) then it needs to be on as well.

Personally I just leave it switched on all the time. You could switch it on and off as and when you require it, and this will presumably make an improvement (albeit pretty small) to your efficiency and range as you are not drawing power to run the A/C pump.

 

[anko]

So it match be better to start 20 min pre-heating and go out tic the car after around 15-19 mins, disconnect charger and drive off? Also I don’t understand what the *-symbol is? Is that only relevant to cooling/AC during the summer? Because it seems to warm up to my desired temperature now, and turning on/off the * doesn’t seem to do anything with regards to temperature or range.

I don't know what the impact on battery health will be. But if there is an impact, that will be when. There are other reason to take of just before pre heating is over. You don't allow the car to cool off again

 

[elm70]

What I know, is that every Lithium battery it is not happy to be left fully charge for long time.
Lithium battery last longer if left with 50 to 25% state of charge .. having left for long time with higher charge it cause to develop higher internal resistance that cause limitation on deliver power and reduce the capacity and efficiency

(This is why our PHEV does never charge 100%, only 4.1v per cell is used as max, and never 4.2 that is the safe max charge)

So ideally the PHEV should be fully charge ONLY just before the car need to be used. Else we have every days hours with max allowed SOC, which cause battery degradation .. having every night 8 hours with the battery fully charged it is not ideal for me ...

In my case I'm programming to have the car to start charging only after mid night, this means I will have the car fully charge only for few minutes/hours before my morning usage

Pre-heat the car ... does not have any impact on battery health

PS: Life time of Lithium battery on the laptop, which are similar to the battery used in the car .. is normally only 3 years, this is because most of people use all the time the laptop connected to DC, and the battery is all the time fully charged .. and this "kill" very fast the battery ... same of BEV and PHEV left for long time fully charged ... just seen an ADV for a Tesla Roadster with less then 500miles .. but with damage battery ... people left it fully charged for years, and battery died because of it.

 

[gorjan]

Thank you for all your replies. All in all, it seems like it´s best to keep it plugged in after charging until just before the pre-heat is done. But it would be best not to leave it connected to the charger too long. But I find the scheduling quite unpractical. Mostly because the car won't charge outside of the set times, though this can be overcome by pressing the "timer-off"-button on the remote. :?

Also, do you know if the power consumption for the pre-heating is 100 % from battery or something like 50/50 between charge cable and battery?

 

[anko]

But I find the scheduling quite unpractical. Mostly because the car won't charge outside of the set times, though this can be overcome by pressing the "timer-off"-button on the remote. :?

Sounds like just what you would want to me :?

Also, do you know if the power consumption for the pre-heating is 100 % from battery or something like 50/50 between charge cable and battery?

When not connected, obviously it is 100% from the battery. When connected it is less than 100% (otherwise it would not make any sense to leave it connected), but more than 0%. How much more depends on your charger. On the standard 10 amps charger it will be more, on a 16 amps charger it will be less.

From the top of my head consumption during pre-heat is approx. 4400 - 4800 watts (depending on settings). The charger will provide 2200 (10 amps version) or 3300 (16 amps version) watts. The rest will be taken from the battery.

 

[vs2]

I have had a Bose Sounddock with a 19v Li-ion battery pack for 8 years and I leave it plugged into 220v 24/7. The battery to me is as good as the day I brought it. I have many top brand items with Li-ion batteries that I leave plugged in 24/7 and after years of use they are still good.

I treat my PHEV the same way. I get into my garage and plug it in until I use the car again. I do this no matter what the charge state of the battery is. It is just a habit now and I know I have a full charge when I go to use the car. You compare my battery to yours in 5 years or so and I doubt you will see much difference.

What I know, is that every Lithium battery it is not happy to be left fully charge for long time.
Lithium battery last longer if left with 50 to 25% state of charge .. having left for long time with higher charge it cause to develop higher internal resistance that cause limitation on deliver power and reduce the capacity and efficiency

(This is why our PHEV does never charge 100%, only 4.1v per cell is used as max, and never 4.2 that is the safe max charge)

So ideally the PHEV should be fully charge ONLY just before the car need to be used. Else we have every days hours with max allowed SOC, which cause battery degradation .. having every night 8 hours with the battery fully charged it is not ideal for me ...

In my case I'm programming to have the car to start charging only after mid night, this means I will have the car fully charge only for few minutes/hours before my morning usage

Pre-heat the car ... does not have any impact on battery health

PS: Life time of Lithium battery on the laptop, which are similar to the battery used in the car .. is normally only 3 years, this is because most of people use all the time the laptop connected to DC, and the battery is all the time fully charged .. and this "kill" very fast the battery ... same of BEV and PHEV left for long time fully charged ... just seen an ADV for a Tesla Roadster with less then 500miles .. but with damage battery ... people left it fully charged for years, and battery died because of it.

 

[elm70]

I have had a Bose Sounddock with a 19v Li-ion battery pack for 8 years and I leave it plugged into 220v 24/7. The battery to me is as good as the day I brought it. I have many top brand items with Li-ion batteries that I leave plugged in 24/7 and after years of use they are still good.

I treat my PHEV the same way. I get into my garage and plug it in until I use the car again. I do this no matter what the charge state of the battery is. It is just a habit now and I know I have a full charge when I go to use the car. You compare my battery to yours in 5 years or so and I doubt you will see much difference.

How do you know that the 19v battery pack is as good as 1st day ?

Did you connect to a charger , and verified the internal resistance and capacity at day one and now ?

It is relative well known that leaving the battery fully charged do cause permanent damage to the Lithium battery.

I also learn in the hard way .. back in 2001/2002 (at the time there was not much knowledge) .. when I stop for multiple years to use my RC models batteries .. all my Lithium battery left fully charged where practically useless ... battery pack capable to deliver over 15A with minimum voltage drop ... after check them again there were capable do deliver just 4 or 6A with huge voltage drop .. capacity did decline around 30 to 40% ... but for high current discharge, so for high power application the capacity was possibly 10% or better not even usable anymore

As far I remember ... at high voltage the Lithium battery tend to oxidase faster ... so it is never a good idea to left for long time fully charged

PS: My PHEV is now 4y old and have 93% capacity compared to new, mainly the previous owner for the first 2.5 years of life did damage the charger, and stop to charge the car .. and consequently the car was all time with low voltage battery ... people that keep the PHEV all time charged, I'm sure even if their PHEV is younger they don't have the same battery condition as mine.

PS: The battery in our PHEV is supposed to deliver up to 60kw power .. from a 12kwh pack .. it means they should be capable to be discharged at 5C rating or in just 12 minutes (at 125km/h continuously will practically match this scenario) ... this is consider a relative high rate of discharge, and if the internal resistance rise ... efficiency is highly compromised .. and voltage will drop so fast that car will believe battery is already 30% SOC even if much more energy is inside, but not usable or usable only at low discharge or at lower provided voltage. .. Different story on a Lithium battery designed to work on a low power application .. something that should run continuously for 2 or 3 hours before the battery will be fully discharged .. I guess your Bose Sounddock is not designed to work for just 20min .. but possible should run for hours with the 19v battery pack.

PS: !9v pack sound strange .. if use 3.7v cells .. it should be a 18.5v pack ... if use 3.6v cells should be 18v .. in case use LiFe battery .. then it will be a 19.8v

 

[elm70]

Thank you for all your replies. All in all, it seems like it´s best to keep it plugged in after charging until just before the pre-heat is done. But it would be best not to leave it connected to the charger too long. But I find the scheduling quite unpractical. Mostly because the car won't charge outside of the set times, though this can be overcome by pressing the "timer-off"-button on the remote. :?

I'm using the car scheduler for pre-heat my car every morning (except on summer :mrgreen: )

I'm not using the car scheduler for charge at specific time (it was not working fine when I did try, plus it has huge limitations) .. instead I have a cheap timer on the "wall" plug that provide power only between midnight and 6am .. and between 1pm to 3pm (I have cheap electricity between 1pm to 3pm and from 10pm to 6am)

During the weak I always plug my car to the charger as soon as I come back .. but it will be charged automatically only after midnight

In the weekend, depending the type of trip I have to make and how much range is left ... I may leave the car un-plugged

Clearly in case of special need .. I can always bypass the timer on the wall plug.

PS: Actually my morning pre-heat happen when charging is not more possible .. but I have no range issue on my daily commute, so it is cheaper for me to use the cheap energy from the battery then not for the power line.

 

[gorjan]

Thank you for your replies. Is there an easy way to check battery health, without using any additional equipment?

 

[anko]

Thank you for your replies. Is there an easy way to check battery health, without using any additional equipment?

Yes. Check how far you can drive before the engine kicks in.

 

[gorjan]

 

[user 816]

Ah! the first frost of the year this morning.. awoken by the jarring sound of the neighbours scraping their windscreens, a timely reminder to reach for my phone from the bedside and activate pre-heating knowing a warm and defrosted car will awake me later...

 

[maby]

Thank you for your replies. Is there an easy way to check battery health, without using any additional equipment?

Yes. Check how far you can drive before the engine kicks in.

true, but you must take into account the weather conditions - an EV range that might be considered good in the cold weather could be considered very poor in warm weather......

 

[vlado61]

I used for the first time the preheating function on my PHEV II app this morning - ( I got my Juro 2017 only 6 days ago - so still learning the ropes).
I programmed the app for 10 min preheating. 2 minuets later I found the car was not very warm. Was it the cold and snow today or 10 min are not enough. How long do you preheat your car for?

 

[Daff]

20 mins should be enough to defrost and take the chill off the interior. You might need a bit longer for heavy frost. I don't think it will clear snow. Haven't tried. The reason it takes a while is the electric heater warms up the engine cooling system and the heat to the cabin is indirectly provided from that.

Steve