En-Route battery warm up doesn't work on my car

[David99]

2014 Model S 85.
firmware 2019.16.1.1 697c2ff
En-Route battery warm up was specifically mentioned in the release notes when I recently updated.

This early morning I headed to a supercharger with a cold battery power limiter was visible from the start. Through CAN bus data I monitored the battery temperature and battery heater activity the entire time. The battery heater did not turn on the entire drive.

I plugged in at the supercharger and the power was lower than what I would normally see. Sure enough, the battery heater kicked in shortly after I plugged in. It stayed on until the battery had reached aprox 28 C (82 F). I have seen this behavior many times before, long before the recent software update. When charging at a supercharger and the battery is not warm enough, it will turn on the battery heater to warm up the battery.

Clearly the battery needed to be warmer for best supercharging speed, yet the car did not warm up the battery on the drive. Only once the car was plugged in did the active heater kick in. Now I'm not saying it doesn't work at all. It most probably works just fine for Model 3 and 100 Model S/X. I assume they just don't bother making changes to the old cars.

 

[Ande]

Did you enter SC as destination ? (So that the car had chance to prepare)
And , was the SoC maybe below some threshold where it did not use energy to hear the pack ?, Or higher that some threshold so that it could not charge at high rate anyway ?
Usually if theres a feature you don't get, then it is gone from your release notes too.

 

[David99]

Did you enter SC as destination ? (So that the car had chance to prepare)
And , was the SoC maybe below some threshold where it did not use energy to hear the pack ?, Or higher that some threshold so that it could not charge at high rate anyway ?
Usually if theres a feature you don't get, then it is gone from your release notes too.

Yes the supercharger was the destination.
I arrived at 8% battery.
I have seen the car turn on the battery heater when I started driving with only 5%. It seems the gain of capacity by heating it is greater than the loss from running the battery heater. In other words, the car will use the battery heater even when the battery level is very low.

I believe the release notes are the same for every car, but the actual functionality is not implemented in the old cars.

 

[Snowstorm]

I arrived at 8% battery.

Maybe the battery heater didn’t turn on because the SOC is too low?

 

[Saghost]

Yes the supercharger was the destination.
I arrived at 8% battery.
I have seen the car turn on the battery heater when I started driving with only 5%. It seems the gain of capacity by heating it is greater than the loss from running the battery heater. In other words, the car will use the battery heater even when the battery level is very low.

I believe the release notes are the same for every car, but the actual functionality is not implemented in the old cars.

I thought the car normally disabled the battery and cabin heat below 15%?

 

[ewoodrick]

Why would you expect the heater to come on in the spring in SoCal?
It's designed for cold weather, not SoCal

 

[Ostrichsak]

Why would you expect the heater to come on in the spring in SoCal?
It's designed for cold weather, not SoCal

I was going to postulate that perhaps the batteries were already warm enough based on whatever algorithm they have in place for en route warming.

 

[TMeister]

Several other experiments come to mind.

- Make a run with SOC above 20% with the local SC as the destination
- Set a distant SC (or something else) as the destination which would require a stop at your local one to continue to the distant one, then see if heating occurs

I've tried your experiment and batteries appear to not get heated. Evidenced by low starting rate that climbs and then levels off. I can monitor the CAN bus but didn't that time. Will do so on the next visit in a few days time. I was going to do the second experiment as well.

The logic here is that if your destination is the SC, there would be no need to get a quicker charge since you are pretty much stating you will be staying there. Adding a distant destination would change the logic to get you in and out of the local SC as quick as possible.

 

[jcarp09]

I would think that on route battery warm up would be active whether you're stopping at a SC for 20 mins or if it is your final destination. Ultimately, this feature is to reduce charge times at SC's regardless if its your final destination.

 

[David99]

I thought the car normally disabled the battery and cabin heat below 15%?

Not sure where you heard or read this, but for sure the cabin heater and AC works normally all the way down to 0%. I have driven my car down to 0% many times and the AC/heater work fine all the way to 0. Cabin overheat protection and keeping the climate control running while parked is disabled below 20% I think. In the early days the AC/heat was reduced when the battery was running low, but they changed at with a software update.

Looking at the battery heater activity I have seen it turn on many times below 15%.

Why would you expect the heater to come on in the spring in SoCal?
It's designed for cold weather, not SoCal

Because the algorithm isn't based on location or seasons, but on battery temperature The battery was at aprox 20 C when I arrived at the supercharger. The car then decided that this isn't warm enough to get the best supercharging speed and turned on the battery heater. at aprox 28 C the battery was warm enough and the battery heater switched off.

I was going to postulate that perhaps the batteries were already warm enough based on whatever algorithm they have in place for en route warming.

If that was the case the car would not have turned on the battery heater when I stared charging. The battery heater kicking in and the charge rate being lower than normal, are a clear signs that the battery was not warm enough. As mentioned, I have seen the battery heater turn on at the supercharger many times when arriving with a "cold" battery. This has been a feature for many years. The new 'en-route battery warm up' was supposed to do the exact same thing, except take care of this ahead of time while on the way to a supercharger. Based on my experience the behavior on my car is the exact same as it always was despite the release notes. That's why I'm thinking they didn't include the old cars.

A similar example of a new feature that never made it to the old cars is the 'torque sleep' feature. In RWD cars it should de-energizes the entire drive unit when the car is not in motion. My measurements show it does not work. I can manually do it and reduce the power draw by aprox 400 Watt.

Anyways, the whole thing is not a big deal. I don't really care as the situation of arriving at a supercharger with a cold battery is extremely rare. Almost every time I use a supercharger it's because I have driven so much that I'm running low on the battery. That means I have usually driven enough for the battery to be plenty warm.

 

[AWDtsla]

2014 Model S 85.
firmware 2019.16.1.1 697c2ff
En-Route battery warm up was specifically mentioned in the release notes when I recently updated.

This early morning I headed to a supercharger with a cold battery power limiter was visible from the start. Through CAN bus data I monitored the battery temperature and battery heater activity the entire time. The battery heater did not turn on the entire drive.

I plugged in at the supercharger and the power was lower than what I would normally see. Sure enough, the battery heater kicked in shortly after I plugged in. It stayed on until the battery had reached aprox 28 C (82 F). I have seen this behavior many times before, long before the recent software update. When charging at a supercharger and the battery is not warm enough, it will turn on the battery heater to warm up the battery.

Clearly the battery needed to be warmer for best supercharging speed, yet the car did not warm up the battery on the drive. Only once the car was plugged in did the active heater kick in. Now I'm not saying it doesn't work at all. It most probably works just fine for Model 3 and 100 Model S/X. I assume they just don't bother making changes to the old cars.

How far did you drive and what was the starting SoC? If you navigate to a supercharger close enough, you should be able to start the battery heater while parked.

I think it's likely that if you start driving not quite far away enough, and with low enough SoC, that by the time it wants to heat the battery as you're approaching the SC because your battery is still cold, you will have too low SoC to do so.

 

[David99]

How far did you drive and what was the starting SoC? If you navigate to a supercharger close enough, you should be able to start the battery heater while parked.

I think it's likely that if you start driving not quite far away enough, and with low enough SoC, that by the time it wants to heat the battery as you're approaching the SC because your battery is still cold, you will have too low SoC to do so.

I drove 20 miles and arrived at 8%. I had maybe 22% when I left. I have seen the battery heater turn on at lower levels so I don't think SoC had any influence.

 

[AWDtsla]

I drove 20 miles and arrived at 8%. I had maybe 22% when I left. I have seen the battery heater turn on at lower levels so I don't think SoC had any influence.

You should probably try it from a higher SoC before declaring it inoperable. If I was writing that algorithm, I wouldn't turn on the battery heater either if 8% SoC was estimated at arrival. Might be 3% with the heater on.

 

[David99]

You should probably try it from a higher SoC before declaring it inoperable. If I was writing that algorithm, I wouldn't turn on the battery heater either if 8% SoC was estimated at arrival. Might be 3% with the heater on.

The battery heater uses aprox 1% battery capacity per 10 min of running at full blast. When I plugged in, the battery heater turned on for maybe 4 minutes, then the ideal temperature was reached. I don't think SoC has anything to do with it as I have seen the battery turn on when I was driving at 2% battery and had nothing set in my navigation.

As I said before, this feature is not making a whole lot of difference in the real world. Most of the time we head for a supercharger after we have driven for a while so the battery is already warmed up from driving.

 

[AWDtsla]

The battery heater uses aprox 1% battery capacity per 10 min of running at full blast. When I plugged in, the battery heater turned on for maybe 4 minutes, then the ideal temperature was reached. I don't think SoC has anything to do with it as I have seen the battery turn on when I was driving at 2% battery and had nothing set in my navigation.

If it only had to turn on for 4 minutes, it really didn't need to turn on at all.

As I said before, this feature is not making a whole lot of difference in the real world. Most of the time we head for a supercharger after we have driven for a while so the battery is already warmed up from driving.

Says you from California. Go somewhere North in the winter and you might be in for a 1-hour battery warmup, and an initial charge rate of 0 without it. You're just not in a place to test this feature.

 

[Uncle Paul]

Battery preconditioning probably has an algorithm the determines when it will be used. If you set you Nav to arrive at a supercharger with 10% buffer, then the preconditioning probably would not work in your specific case.

If the ambient temperature was above a certain amount, again it may not engage the heater as it may not provide much benefit.

With your technology you might be able to try under different circumstances to get an idea when and where it engage.

 

[David99]

If it only had to turn on for 4 minutes, it really didn't need to turn on at all.

Obviously the car thought it was worth turning it on. And clearly the charge rate was reduced because of temperature.

Says you from California. Go somewhere North in the winter and you might be in for a 1-hour battery warmup, and an initial charge rate of 0 without it. You're just not in a place to test this feature.

I have been up in Wisconsin with my for the last 4 winters, so I know very well what cold weather is. I have been able to read my battery temperature among other data so I know from many years of experience how battery temperature affects the car, charging, driving, ...

 

[David99]

Battery preconditioning probably has an algorithm the determines when it will be used. If you set you Nav to arrive at a supercharger with 10% buffer, then the preconditioning probably would not work in your specific case.

This feature is meant to increase supercharging speed. It doesn't matter if you arrive with 0% or 10% or 25%. If the battery is colder than the ideal temperature for supercharging, the charge rate is reduced and this feature is supposed to kick in exactly in those situations.

 

[AWDtsla]

Obviously the car thought it was worth turning it on. And clearly the charge rate was reduced because of temperature.

If x < y then do something

I have been up in Wisconsin with my for the last 4 winters, so I know very well what cold weather is. I have been able to read my battery temperature among other data so I know from many years of experience how battery temperature affects the car, charging, driving, ...

You're certainly not testing on-route battery warm up there.