OVMS Module and Cooldown

[ViviV]

@markwj thank you for referring me to this thread. I am so happy to be learning about the importance of cooling down the battery. Recently I have started doing the manual method of range charging for 45-60 minutes at 13 amps as recommended in another thread, although today temp went down to 82 F in about 45 min, but 10 min later was back to 86 F so I unplugged it. Was this because it started charging and temp goes up and down? This manual method works as long as I set an alarm to remind me to unplug.

Anyways, I would like to learn to do the cooldown via OVMS as described in this thread. I am working on getting SMS to work from Hologram, but in the meantime, the app seems to work.

The information in this thread was super helpful, but I have a few questions for the experts.
1) In this thread there are 2 different references to what to enter in the OVMS phone app in Control>Parameters #15. Should it be just "1" to turn it on (default is 31:60) or should it instead be "30:60" (the 30 being what ever temp in C you want the battery to reach and 60 being the max time in minutes for cooldown)? Or does 1 = 31:60 and if you want anything other than the default you need to enter the actual desired temp and time? Is my setting correct in the screen shot image?

2) Related question...how do I check that COOLDOWN parameter is working?

3) Seems like 30 C (86 F) is high as an endpoint, in other threads I have seen desirable temp as ~26 C (~78 F) -- is there a downside to setting it lower, like to 26:60?

Screen shots of my settings and OVMS firmware versions. Is everything correct?

 

[markwj]

You will need feature #15 set to 1 (to allow OVMS to write to the car's CAN bus).

Parameter #15 is the cooldown parameter. 30:60 is fine for that, as a starting point.

Features and parameters are two different things. On the App, you should find them both next to each other on the menu preceeding the screenshots you give.

When cooldown is working, it will appear as a normal charge to the App. So you should be able to see low-amperage range mode chargers, etc.

You should initiate the cooldown either via an SMS 'cooldown' command, or using ACC (Advanced Charge Control) to automate it.

 

[ViviV]

@markwj
I apologize for confusing the feature and parameter. I've got it now. Thank you very much.

should be able to see low-amperage range mode chargers

Can you post a screen shot of how it would look different from a normal charge? is it just that it will automatically select range mode?

You should initiate the cooldown either via an SMS 'cooldown' command, or using ACC (Advanced Charge Control) to automate

I will email you at OVMS support because I have never been able to get SMS commands to work from Hologram, perhaps I have a setting wrong. As for the ACC, I see parameters 16-19 for ACC, but I am not sure of the syntax to automate the cooldown in these fields. Are there instructions you can point me to?

 

[markwj]

Can you post a screen shot of how it would look different from a normal charge? is it just that it will automatically select range mode?

It will just look like a range charge.

Are there instructions you can point me to?

The manual is the best we have:

https://github.com/openvehicles/Ope.../master/docs/OVMS_UserGuide_TeslaRoadster.pdf

For manual control, it should be as simple as enable feature#15=1, leave parameter #15 default (31:60), and SMS 'COOLDOWN' to start the cooldown. Please make sure you are running the Tesla Roadster specific firmware (not the general production firmware, which has cut-down feature set to be able to support as many cars as possible).

ACC is a bit more tricky to setup.

Both require SMS.

 

[Rolf68]

Hello people.

I exhume this thread Now the OVMS 3 is available and seems to be bluetooth / wifi / SMS compatible.

The summer was really hot here and when driving I saw the battery pack hit high temperature levels.

The question is : with the new hardware, is it possible to use the application to make a battery cooldown while driving ? I know that sometime the car cools itself down when temperature is high (happened to me already) so I hope there would be a way to ask it to do that using a phone .

Thanks for any info

 

[gregd]

I don't think you can do a cooldown while driving with the OVMS, at least not the way it currently works. The current algorithm makes use of "Range Mode" charging, which puts a preference on cooling the battery pack first before trying to push energy into it.

However, there is an alternative, if I can find the reference. It involved adding a switch to the wiring in the center console, to force the valve to the ESS cooling open. It was posted here somewhere...

EDIT: Ha! Found it:
Manual battery cooldown mod - a cure for the Roadsters insomnia

 

[markwj]

The question is : with the new hardware, is it possible to use the application to make a battery cooldown while driving ? I know that sometime the car cools itself down when temperature is high (happened to me already) so I hope there would be a way to ask it to do that using a phone .

There is no way I know of to do this in software. Even the cooldown while charging is kind of kludgy (manipulating charge modes to try to nudge the car in the direction of turning on the HVAC), and not a standard feature of the car firmware.

 

[Rolf68]

@gregd and @markwj Thanks for the answers . I knew about the switch hack but I wanted to check first if it would be doable without wiring things. I hoped the new version of the OVMS would have some magical capabilities

Thanks again and have a nice day

 

[markwj]

I hoped the new version of the OVMS would have some magical capabilities

Well, we are now connected to 3 CAN buses (original was just 1), including the HVAC one. So, we _could_ send the command to start the HVAC. But really too chicken to mess with it. Too easy to blow something.

 

[Rolf68]

Well, we are now connected to 3 CAN buses (original was just 1), including the HVAC one. So, we _could_ send the command to start the HVAC. But really too chicken to mess with it. Too easy to blow something.

I understand. Thanks for the explanation

Best regards

 

[m1k3]

Well, we are now connected to 3 CAN buses (original was just 1), including the HVAC one. So, we _could_ send the command to start the HVAC. But really too chicken to mess with it. Too easy to blow something.

Since this thread has been exhumed, I guess this is as good a place as any to ask about this feature. I'm trying to get cooldown working on a v3 module (2.5 Roadster).

xtr (readable writeable)
cooldown: 1
cooldown.current: 10
cooldown.templimit: 31
cooldown.timelimit: 60

When I execute "charge cooldown" via shell, the car just starts range mode charging at 10a. All of my temps are above 35C I missing something?

 

[slcasner]

The way the cooldown process works is to cycle in and out of range mode charging at a current that is low enough so that all of the energy goes to cooling and there is not enough left to increase the charge level significantly. (The point being that one might want to cool the battery at an hour of the day when electricity prices are high.)

When I was testing cooldown on my 1.5 Roadster, the setting of 10A didn't work. The lowest that that car would allow was 12A, otherwise the charge current stayed at the 32A setting allowed by my EVSE. Mark changed the default cooldown rate from 10A to 12A (maybe just for USA roadsters?) a year ago. Is your 2.5 working at 10A?

 

[m1k3]

The way the cooldown process works is to cycle in and out of range mode charging at a current that is low enough so that all of the energy goes to cooling and there is not enough left to increase the charge level significantly. (The point being that one might want to cool the battery at an hour of the day when electricity prices are high.)

When I was testing cooldown on my 1.5 Roadster, the setting of 10A didn't work. The lowest that that car would allow was 12A, otherwise the charge current stayed at the 32A setting allowed by my EVSE. Mark changed the default cooldown rate from 10A to 12A (maybe just for USA roadsters?) a year ago. Is your 2.5 working at 10A?

Oh ok. I don't know why, but I was under the impression that putting it in range mode meant that it wouldn't start charging until the desired temperature was reached. That's a misunderstanding on my part.

Issuing the "charge cooldown" command seemed to start a 10A charge on my vehicle, but I was tinkering with so much stuff I can't for sure say that I didn't manually change the charge settings which would obviously explain why it worked. I'll test it again and report back to confirm.

To be clear, the only temp I should be watching is the battery temp, correct? Even if the car is only pulling 10A or 12A, I would assume there's no way to keep the PEM and charger below like 40C.

 

[slcasner]

Right, the purpose of the cooldown operation is to cool the battery using the air conditioning system. The PEM is only cooled by ambient air so the cooldown operation can only make the PEM warmer. That's considered to be less critical, so long as it doesn't get too hot.

 

[sethr]

I've been leaving my trunk open during charging/cooldown to keep the PEM a bit cooler; not sure how much it's really doing, but the air above the PEM feels pretty warm. Certainly can't hurt....

 

[m1k3]

Right, the purpose of the cooldown operation is to cool the battery using the air conditioning system. The PEM is only cooled by ambient air so the cooldown operation can only make the PEM warmer. That's considered to be less critical, so long as it doesn't get too hot.

Thanks. Makes sense.

 

[m1k3]

I've been leaving my trunk open during charging/cooldown to keep the PEM a bit cooler; not sure how much it's really doing, but the air above the PEM feels pretty warm. Certainly can't hurt....

Well in theory, it could hurt if there's a designed airflow you're interfering with. For example, a 1U computer server is designed to bring fresh/cool air from the front of the chassis and exhaust it through the rear. Removing the lid of the chassis impairs the ability of the fans to pull in the air from the front and push it through the back of the chassis.

I'm a newer Roadster owner, so I don't know enough to say that opening the trunk lid creates a similar scenario for the PEM. I'm just pointing out that it is a possibility.

 

[im4uttx]

I'm not positive, but since the PEM is cooled specifically by air being pushed through the duct attached to the bottom of the PEM, I don't think leaving the trunk open would negatively impact the cooling, and depending on where the air leaves the PEM, should improve it some, but probably not significantly.

 

[Frisco-Dad]

Thanks for resurrecting this thread. I’ve been trying to set the Cooldown parameters, but I get the error listed here: Parameter key not supported.

Any help is appreciated, thanks.

 

[m1k3]

Thanks for resurrecting this thread. I’ve been trying to set the Cooldown parameters, but I get the error listed here: Parameter key not supported.

Any help is appreciated, thanks.

View attachment 449485

I was getting this error too. I ended up changing the settings via the command line:

config set xtr cooldown 1
config set xtr cooldown.current 12
config set xtr cooldown.templimit 31
config set xtr cooldown.timelimit 60

Just go to "tools > shell" in the web interface of your module and enter those commands and it should work.