Effect of heat on ICE auto-shutoff
 

It's been around 104 degrees consistently here in the afternoons since the last couple of weeks or so. One strange behavior I am noticing is that it seems to take far longer for ICE auto-shutoff than before.

I have to drive a good 15 to 20 min before it'll shut off the ICE when I am stopped at a light, whereas usually (or even now, in the mornnings) it only takes about 5 min of driving for ICE to start autoshutoff below 40mph or stop.

The only reason I can think of is that it's trying to cool down the batteries. I have so far managed to continue using Eco air mode, but it sure isn't easy boiling in those temps.

Anyone here noticing similar issues when it's pretty darned hot outside?

Re: Effect of heat on ICE auto-shutoff
 

Where I live it's pretty darn hot 6 months out of the year. When I leave work in the afternoon, the FEH needs a good 5 miles of driving to cool the HV battery pack to below 95, at which point I can go EV. Before that, I FAS at every light to avoid idling. I bought a couple of blue ice packs that I put on top of the pack, but it needs a good half hour of soak time to lower the temp any. In a humid climate I might be worried about excessive condensation, but in Phoenix it's not a problem.

Re: Effect of heat on ICE auto-shutoff
 

It sounds like it is the battery A/C not working properly. If the cabin A/C feels cold, I suspect it may be a valve or door not closing properly in the battery cooling system. You can take out the battery filter and see the vent door to make sure it's closed when park and the engine off.

It's hot here in Florida also and I never drive more than a few minutes to go EV. If you do the double tap of the brake pedal in drive while moving, it should go EV if everything is warmed-up. When my battery is to hot to go EV, I tap the brake pedal in neutral a few times lightly and always go EV.

If the battery A/C is working properly, you should be able to go EV in temperatures above 110F with no problem. You just may not stay in EV long before a restart to cool things down again with the A/C though.

GaryG

Re: Effect of heat on ICE auto-shutoff
 

You can never go EV after a few minutes when it's 110F here, and I doubt a 2008 Mariner's A/C is already failing. There is too much thermal mass in the battery pack to be able to cool it very fast. If you can drive 65 on the freeway, you can cool it down faster. In the mornings when it's only 90 or so, I can go EV in a mile or less. Even with a windshield screen and the windows cracked, when I get in my FEH at 5:30pm in the summer after being in the parking lot all day, the inside temp is ~160F and the battery is usually around 46C. No way to go EV any time soon.

Re: Effect of heat on ICE auto-shutoff
 

I get something of the same effect here in Denver when the battery has been sitting in the sun all afternoon. I've used the LCD test mode to watch the battery temp, and the AC is definitely cooling it down, but it does take quite a while to get low enough to go EV.

I've wondered if one of those solar powered window fans would keep the interior cool enough to make a difference, but have never actually bought one.

Re: Effect of heat on ICE auto-shutoff
 

Wow I thought I was loosing my mind. Since the temps have been in the 100s here I have noticed it takes allot longer to gat to ev and it has killed my fe about 1.5 mpg.

Re: Effect of heat on ICE auto-shutoff
 

Carl, I forgot the last time I passed through Phoenix during the summer at 110F in the shade. No question the battery and everything around it becomes a heat sink in that weather. Now I see why your ID is DesertDog.

I went though the desert and Phoenix in a car with no A/C, and I'll never do that again. I remember we rolled the windows up because the heated air coming through the windows was to much. After a few minutes of sweating, we rolled down the windows to dry off to feel a little cooler. Got a hotel as soon as I got to Phoenix just to have room A/C till it got dark.

One thing I just notice that doesn't help RB is his '08 is black, and I see no window tint on the front windows. That is SOP for me in Florida and I also keep a windshield screen and the windows cracked while parked. The solar fan is another good idea.

It has never been hot enough, even parking in the sun to effect EV for me. Even when I add the extra charging and the battery gets hot, I go EV in neutral with no problem. If you guys are having problems going EV, try the brake pedal taps in neutral. It works in the cold here (34F) for me also.

GaryG

Re: Effect of heat on ICE auto-shutoff
 

The double tap works most times for me, but not when the battery is too warm.

Re: Effect of heat on ICE auto-shutoff
 

Salsbr, are you saying tapping the brake pedal does not work in neutral to go EV when the battery is hot also?

During the MPG Challenge, Debbie Katz said I was going EV a lot easier than she did. She also said I used neutral coasting more. Just understand I never use the double tap in "D" anymore. Either I use the LGA or tap in neutral when things get hot.

GaryG

Re: Effect of heat on ICE auto-shutoff
 

It is in the battery management software to require A/C cooling when the battery pack temperature hits 38'C ( 100.5'F ) or above. This in effect, disables EV.

Between 31'C and 37'C ( 88'F to 99'F ) the A/C will be used to cool the battery pack only when the engine is running for other purposes. You can get EV, but sometimes it takes a few seconds longer as the car waits for the A/C to stop the compressor before stopping the ICE.

Below 31'C, A/C cooling is usually not used for the battery pack.