Interesting finding about Range Mode

[gavine]

I'll try and make this simple (and hopefully accurate). Range mode is basically for times when you are going on a long trip and plan on getting on the highway soon. There's no need to warm the battery for highway cruising so range mode off would waste energy heating the battery for no reason. On non-highway trips, it makes sense to warm the battery in order to enable regen. Range mode is also good for those very short trips (like picking your kid up at the bus stop) where warming the battery is a waste of energy that you won't recover. Sitting in the car waiting for the bus and warming the battery only to drive 3 blocks home is a waste.

 

[scaesare]

Well now I'm more confused. The first few posts of this thread indicate that range mode on seems to warm the battery by sending warmer fluid (100F)into the battery with cooler fluid leaving the battery. Turning off range mode would reduce the fluid temperature going to the battery. So I was under the impression that Range Mode on meant a warmer battery created by the inverter/drive unit and disabling of the battery heater, and that Range Mode off meant lower battery temperature by utilization of the battery warmer. I'm not sure which Range Mode settings yields a warmer battery and which mode warms the battery faster, but sounds like Range Mode on means a warmer battery.

The key is that RM reduces (eliminates?) active heating or cooling of the battery. The fluid circulation you’re referring to is passive in the sense of not consuming additional energy to run a resistance heater or AC compressor.

@maximizese I think you are missing the point that there are multiple sources of heat (as @jgs points out) that can be funneled in to the pack: The 6KW electric coolant heater and waste heat from the drive unit. The former consumes energy to generate heat, the latter produces heat for "free". The video mentions this at about 5:30.

Range mode disables (or reduces) the usage of the glycol heater. Even with range mode enabled, there still can be warm fluid from the drive unit that can be valved-in to circulate through the pack. It will obviously enter the pack warmer and exit cooler as it transfers heat in to the pack. The point is that this may not impart as much heat in to the pack as quickly, as the drive unit won't average 6KW of waste heat.

While the discussion of the fluid inlet temperature at about 10mins in to the video correctly mentions that the pack target temps do indeed change with range mode enabled, it doesn't say that it's the electric coolant heater... I wouldn't assume that... it's more likely using deive unit waste heat.

 

[AWDtsla]

Range mode lowers the active heating target, it does not disable the heater.

I repeat again, again, again, for my car range mode doesn't change the passive target pack temp. I don't know if it ever did, but the forum invents myths of how the car works. Nor does "max battery power" aim for 50C as was said repeatedly for years, everything aims for ~42C**

* in my car
* as of some firmware circa 12/18.

 

[maximizese]

I'll try and make this simple (and hopefully accurate). Range mode is basically for times when you are going on a long trip and plan on getting on the highway soon. There's no need to warm the battery for highway cruising so range mode off would waste energy heating the battery for no reason. On non-highway trips, it makes sense to warm the battery in order to enable regen. Range mode is also good for those very short trips (like picking your kid up at the bus stop) where warming the battery is a waste of energy that you won't recover. Sitting in the car waiting for the bus and warming the battery only to drive 3 blocks home is a waste.

Thanks everyone for the explanation, it is more complicated in both understanding the process and conceptually determining the best use for it but I think you nailed it. One day I'll get my hands on a TM Spy so I can make sure my particular TMS85 behaves accordingly. There seems to be dissent on what actually happens and I wonder if different builds and different firmware among different environments is the reason.

Anyways, having a GPS-linked range mode toggle (similar to Homelink with the Tech package) might be useful for my wife. We live half a mile to the freeway onramp which she takes on her 55 miles drive to the office. The software can ask if you want range mode based on battery temperature, ambient temperature, knowing you're going to take a nearby freeway, and knowing the length of your destination. Of course, this might present more problems when folks want more power available for freeway merging.

 

[scaesare]

Hence my wording of "or reduces usage of the glycol heater".

 

[gavine]

We live half a mile to the freeway onramp which she takes on her 55 miles drive to the office.

Perfect example of when to use range mode. Not that she needs the range per se, but to save energy.

 

[supratachophobia]

Not in my car. Only way to confirm is to get a CAN bus reader. No matter what I do, the passive heating target always seems to be ~42C.

What is that in freedom units?

 

[supratachophobia]

Range mode lowers the active heating target, it does not disable the heater.

I repeat again, again, again, for my car range mode doesn't change the passive target pack temp. I don't know if it ever did, but the forum invents myths of how the car works. Nor does "max battery power" aim for 50C as was said repeatedly for years, everything aims for ~42C**

* in my car
* as of some firmware circa 12/18.

So regardless of settings, the BMS tries to keep a Max temp of 42' C, it just matters how long it takes to get to that temp when using active it passive heading?

 

[David99]

What is that in freedom units?

LMGTFY

 

[David99]

So regardless of settings, the BMS tries to keep a Max temp of 42' C, it just matters how long it takes to get to that temp when using active it passive heading?

Here is what it used to do. (I say 'used' because I believe they changed it recently) The target is a little over 30/85 normally and a little over 40/105 in range mode, but in reality it will deviate from that almost all the time. Here in Los Angeles, it is ends up higher when I drive. In normal mode, the car will warm up the battery if it's under 30. You can see it directing warmer coolant into the battery. It also bypasses the radiators. Of course that only works if there is enough heat losses from the drive unit. Once it reaches the target of 30, it will redirect to the radiators and change the coolant flow to not warm up the battery. Most of the time when driving I found that the battery still gets warmer on it's own, especially when the ambient temperature is half way warm. There just isn't any cooling happening in the radiators when the ambient temps are similar. Most of the time, the battery will end up getting warmer than the 30 degree target. The battery temperature can go much higher. All the way between 10 C to 50 C is fine and the car won't do too much about it. It will redirect coolant from the drive unit to the battery or not, use the radiators or not, but that's it. Only if it goes over 50 C will it actually start using the AC to actively cool the battery. Same with below 10 C. It will use the battery heater. Within the 10-50 C range, the car will do only mild things to control temperature. Outside of those is when active cooling or heating starts.

Recently I have seen in my car a little more aggressive temperature management. I have seen the battery heater stay on for higher than 10 C. I have also seen the car turn on the radiator fans high when the battery was right between 30 and 40 C and I was driving slowly just for a few minutes.

 

[scottm]

Recently I have seen in my car a little more aggressive temperature management. I have seen the battery heater stay on for higher than 10 C. I have also seen the car turn on the radiator fans high when the battery was right between 30 and 40 C and I was driving slowly just for a few minutes.

I'm with you on that.. I think Tesla is dialing up the battery management algorithm into a more aggressive "preserve the longevity of the pack" mode. Even if it takes more energy / heating / cooling... which is "on you" and not them, so a good move from their perspective... But I mostly supercharge these days and it's free for me. So really, the cost is on them for us freeloaders anyway. I'm just happy my pack is being cared for so closely.