Hot days...

[philly_ev]

So I have two questions.

Last night my wife ran out to run an errand and the car sent me a message saying that performance is severely limited due to the heat (it hit 100 here yesterday). It told me to plug in the car (although it was plugged in for 2 hours before she ran her errand and she was back in 10 minutes, so I am not sure how the batteries were not cool anyway). So I plugged in the car (using the 110 because my 220 isn't installed yet). I was reading the forum and many of you have indicated that Ford recommends plugging in the car when not in use (especially on hot days) so the batteries do not get too hot. My question is what do I do while at work where they don't have a spot to plug in at? It's going to be hot this entire week with chances of tstorms popping up throughout the day. So I need to keep my windows closed (because of rain), with the TMS not doing anything (I assume) because its not plugged in. Any recommendations?

Second question - in the my ford mobile app on the iPhone, I am having an issue where the miles are not increasing but the battery percentage is. So this morning it showed the car was 85% charging with 31 miles. That's obviously not correct. I started the car and the miles shot up to 76 miles. Has anyone had this issue?

 

[v_traveller]

1) You can do a remote start, worked for me. Cooled down the battery enough to change the battery performance status from red to green after 5 minutes, then I let the remote start self-terminate (10 minutes total). Depleted my charge by 4%, so it consumed maybe 1kWh. Ths was on a day that hit 105F.

The next day hit 103F, but on that day what I did is I hit the remote start before I got the hot battery message (about 2:30pm, one hour before the first hot battery message on the day before). Seemed to do the trick, FFE didn't send me any messages that day. Ambient was a little lower though, so that may have been a factor.

So if you can afford to lose 4% of your charge, a remote start could help your FFE survive a hot day. Wish there was a way to preset this behavior, and allow an unplugged FFE cool itself off as long as the battery isn't depleted to a level below a user-defined threshold.

2) This happens to me every morning, though the difference isn't as drastic (usually MFM reports about 50-55 miles, then at startup I get 60-65 miles).

 

[philly_ev]

Where do you see the colors for the battery (ie you said it went from red to green)

 

[WattsUp]

Where do you see the colors for the battery (ie you said it went from red to green)

On the MFM website, on the "My Driving" page, under the "Vehicle Info" tab.

Normally, it shows all-green status there, but sometimes the "Battery Performance" status might be red and say "Poor".

 

[philly_ev]

Where do you see the colors for the battery (ie you said it went from red to green)

On the MFM website, on the "My Driving" page, under the "Vehicle Info" tab.

Normally, it shows all-green status there, but sometimes the "Battery Performance" status might be red and say "Poor".

Thanks - I see it. I didn't even notice if it was red yesterday. If it happens again I will take note.

 

[dmen]

You should also try to park in shade and on light surfaces, ie concrete rather than asphalt if possible. In a garage would be great, but under a tree would work fine too. I think the battery has to get warmer than 120F to potentially be impacted. So as long as radiant heat isn't warming your car over the air temp then even in an East Coast heat wave, you shouldn't need to plug in or remote start to save the battery. Of course it isn't always easy to find a shady parking spot...

 

[v_traveller]

Articles and papers available online indicate that 86 degrees F is a limit for Li-ion batteries; anything above is considered "elevated", and that prolonged exposure to elevated temperatures, especially during a high state of charge, will shorten battery life. Based on the "behavior" of my FFE and posts on this forum and MFM, I'm guessing that the hot battery message comes on when the battery approaches 86F. It may take a while for the battery to reach that temperature; in my case, when the morning temp was 70F, noon was about 95F and a max temp of 105F was reached at about 2pm, I got the hot battery message at about 3:30pm when it was still 105F. I agree that if you park your car in a sunny spot over blacktop that's been exposed in 100F+ heat, that the battery should heat up faster due to radiant heat, but even in a shady spot the battery can reach (or at least maintain) over 86F due to high air temperature. In fact, in my case, I didn't even notice the emails from my FFE until late that night (past 10pm), and apparently my FFE was begging to be plugged in every hour on the hour until I remote started it at 1030pm (was still mid-80s at that time).

My state of charge was at about 84%; I suspect that if it were fully charged I would have gotten the hot message much sooner. Perhaps I'll run an experiment two summers from now, closer to the end of my lease term....

 

[dmen]

Articles and papers available online indicate that 86 degrees F is a limit for Li-ion batteries; anything above is considered "elevated", and that prolonged exposure to elevated temperatures, especially during a high state of charge, will shorten battery life.

Thanks, I apparently pulled the 120 out of my butt.

I think it's reasonable to act out of extreme caution and remote start your car when you get the hot battery warning off plug. But I also think it's reasonable to turn off the hot battery warning on My Ford Mobile and just try your best to plug in when you can, park in a cool spot when you can, and still expect a nice long battery life. My understanding is that the battery will suffer from the heat if it stays at a high temp for some time, like weeks to months, at a high state of charge; or more importantly if it is charging or discharging at high temps. So if it sits at 100F for 6 hours being partially depleted after a morning commute, then when you start it up to go home you drive gently at first so as to draw relatively little charge while the battery cooling system does its thing, you have done little if any stress to your battery.

Of course I can take this approach living where it gets above 90F maybe 10 days a year! But it gets below 20F a lot more than that here, and I've received a ton of "it's cold outside, plug me in!" messages. I know these messages can be ignored without risking damage to the battery and that leads me to think the hot warnings are similarly overkill.