Frunk Temperature

azKiaUser said:

So I wanted to know what the max temperature in the frunk could be (during the current heatwave). Obviously this would be dependent on the ambient temperature.

I wanted to keep/store a 12V battery booster--just because...Or maybe a laptop for a day or so.

Lithium batteries don't like high heat and an interior could hit 80C. Most battery boosters have a max storage temp of 60C (I think one was 70C...but can't find it now).

I couldn't find this info anywhere so I decided to test it out for myself. Non-scientific of course

I purchased a Elitech RC-51 Digital Temperature Data Logger and taped it inside my frunk.

I recorded all the temps encountered for a couple days; in my garage as well as a few hours out in the sun.

My MAX temperature in the sun was 46C with an ambient temp of 36C.

This was consistent for a couple days. It appears as though the frunk temp is approx "ambient + 10C".

I found frunk information for a Tesla and it was significantly higher in the frunk (non-scientific...non official specs). I think the EV6 does a better job with insulating the frunk. If you see the pics below it looks like the hood has some type of thermal barrier as well as the (little) frunk enclosure.

Anyway, thought it was interesting...I'll continue logging a few more days and maybe see what the interior temp gets to (my tint is a few weeks away...)

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windracer said:

We still haven't figured out what to store in the frunk ... maybe a flashlight? Most of that kind of stuff (charging cable, etc.) we keep under the cargo deck.

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MikeV said:

Tested the temps in my frunk in the direct Tennessee summer sun yesterday. The front of the car was placed facing west towards the sun for 1.5 hours from 4-5:30pm. A electric thermometer with an internal sensor and external wired remote sensor was used. The probe was placed in the frunk and the front hood was closed. The reported outdoor temp was 95F, the temp in the shade at ground level 106.7F (internal sensor) and the frunk temp was 120.5F (wired sensor). So it looks like the frunk is about 14F warmer than the outdoor temp. Needless to say I will not be leaving my Li 12v battery jumper in the frunk during the summer. You should probably not leave temperature sensitive items, especially batteries, in the frunk.

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MikeV said:

Tested the temps in my frunk in the direct Tennessee summer sun yesterday. The front of the car was placed facing west towards the sun for 1.5 hours from 4-5:30pm. A electric thermometer with an internal sensor and external wired remote sensor was used. The probe was placed in the frunk and the front hood was closed. The reported outdoor temp was 95F, the temp in the shade at ground level 106.7F (internal sensor) and the frunk temp was 120.5F (wired sensor). So it looks like the frunk is about 14F warmer than the outdoor temp. Needless to say I will not be leaving my Li 12v battery jumper in the frunk during the summer. You should probably not leave temperature sensitive items, especially batteries, in the frunk.

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Ucinn said:

It will still probably be cooler than the trunk don't you think?.. also, was this tested on the AWD or RWD version. My understanding is the AWD has extra insulation in the frunk area.

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RSinAZ said:

Nice work AZKiaUser and MikeV. Thanks.
I'm in Tucson and hadn't thought about this as I'm retired, so the car mostly spends it's time in an insulated garage that maxes at 95F even at 110F outside.
I keep a jump starter in the frunk. However, next year it'll be in a Phoenix hotel parking lot for 2+ weeks while I'm in Europe. The car is Interstellar Gray, RWD (did I mention I was retired?). So the dark hood over the frunk seems the worst of a set of poor choices. The car will be charged around 80% when I park it and the 12V top-off seems to be working, so the jump starter was Plan B. I'll stick it under the passenger seat now. It'll help a wee bit. And for Plan C, there's always AAA.

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MikeV said:

You could also keep it in the glove box but in the cabin may be even better.

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azKiaUser said:

Why would the glove box or cabin be better?

Hot Car Calculator | Time to Heatstroke (omnicalculator.com)

Sitting in the sun...the interior gets hotter than any other part of the vehicle (such as the frunk...or so is my proposed theory).

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MikeV said:

My guess is the interior and frunk wind up the same temp but the heat coming off the inverter and front motor should initially raise the temp in the frunk and there is no HVAC cooling it. However when the car is off, the temps will over time be equal. I can test it to see.

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eurosteve said:

I've seen several posts from folks planning to leave their cars exposed to the sun in hot climates for extended periods (like at airport parking). My 2-cents on this is that in general it's a bad idea since one of the main objectives of the game is to keep the high voltage battery cool (for long term battery longevity)... I don't have to tell you that Phoenix is HOT this time of year to begin with (100+ F temps every day). If it was me I would spend the $10 a day or so to leave the car in a covered parking garage than let it sit in the sun and BAKE for days on end. We're talking about a roughly $50,000+ car. The least of your problems is the $70 battery booster... The other problem you're going to run into is the active thermal cooling system (BMS). I'm pretty sure that the car will try to keep cool (in the 100+ heat, sitting in the sun) by running active cooling of the batteries. This will run down your main battery. So you'll come back to a car that's been baking in the sun for 2+ weeks with a main battery run down to 30% or so. (I think active cooling cuts off at some point to save the main battery from depleting too low). My 2-cents - either don't leave the EV6 at the airport at all (and take a shuttle to the airport) or at least park it in a covered garage. Even in the garage you might come back to a depleted main battery due to the heat, but you're at least giving your car a chance...

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eurosteve said:

If it was me I would spend the $10 a day or so to leave the car in a covered parking garage...

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tonester said:

No such thing as $10/day for parking in a public covered parking garage in my neck of the woods...and definitely nowhere near $10/day to park at the covered parking garage at my airport...but I digress.

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