Generating cabin heat while parked

[PoorDick]

New issue, at least for me, after 18 months of ownership. When parked in the garage, plugged in and windows up, something is generating heat inside the cabin. We live at 8,600 feet with temps at night in the 40's and rarely getting above mid 70's during the day right now, but last night at midnight the heat inside the cabin was a whopping 91 degrees. Everything is off, no AC running, no lights except for the tiny lights on the door handles, no gear guard, no weird noises, not anything running at all that I can find, yet the temp inside the cabin was getting heat from somewhere. I rolled down the windows and unplugged and the temp dropped, but am seriously concerned what could generate heat. Any thoughts?

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[HeyEllwood]

Would reach out to Rivian and get this looked at ASAP.

 

[mikehmb]

Aside from the cabin heater, the only meaningful things that could generate that much heat in the cabin would be the audio amp (unlikely) or the inverter (pretty likely).

Do you feel extra heat under the passenger seat? That’s where (I’m told) the inverter is. If it’s warmer down there, that’s your culprit.

Get it to a SC asap, regardless.

 

[COdogman]

@Dark-Fx estimated the temp of that inverter was around 130 degrees. That is plenty to keep the interior of your truck warm.

 

[Craigins]

Charging will generate heat as well. Leave it unplugged if you're worried about it.

 

[Mojoman]

He has a point and idea. Unplug from charger one night and check temp.

 

[Sevn86]

That’s concerning. I wouldn’t park it inside until Rivian takes a look at it. Last thing you want is it catching fire.

 

[Zoidz]

All rechargeable cells generate heat as they are charged (and also discharged) - lead acid, NiCad, Lithium. It's all but certain that's where the heat is coming from. Leave it unplugged tonight and you'll probably find more balanced temperatures inside and outside the car.

If you are concerned that this might be unusual/excessive, put in a service ticket.

 

[DaveA]

Check for horny teens in the backseat.

 

[Thedude]

That’s concerning. I wouldn’t park it inside until Rivian takes a look at it. Last thing you want is it catching fire.

Unless you want a new house, then the gamble might be worth it.

 

[godfodder0901]

All rechargeable cells generate heat as they are charged (and also discharged) - lead acid, NiCad, Lithium. It's all but certain that's where the heat is coming from. Leave it unplugged tonight and you'll probably find more balanced temperatures inside and outside the car.

If you are concerned that this might be unusual/excessive, put in a service ticket.

I get what you're saying, but I have never noticed increased cabin temperatures for any reason other than direct sunlight. Especially at level 2 charging, there shouldn't be anywhere near enough heat generated that the BMS can't manage it to the point it heats the cabin.

A would agree with the recommendation to put in a ticket.

 

[Zoidz]

I get what you're saying, but I have never noticed increased cabin temperatures for any reason other than direct sunlight. Especially at level 2 charging, there shouldn't be anywhere near enough heat generated that the BMS can't manage it to the point it heats the cabin.

A would agree with the recommendation to put in a ticket.

We don't have enough information about the BMS to know what it is doing. But here's a simple thought experiment based on the article link I posted at the bottom.

If you charge overnight to add 100 kWh to the battery, due to efficiency loss, it's going to draw 110 to 120 kWh total power to do so, resulting in 10 to 20 kWh loss as heat. That's a fair amount of heat - that's very roughly equal to running a Pelonis 1500w ceramic furnace continuously while charging. That heat has to go somewhere. In a still air garage with the cabin sitting over top the batteries, and the batteries and inverter thermally bonded to the vehicle, the cabin is a sealed heating chamber.

In the end, only Rivian can tell us if this is "normal" but I suspect it is.

But how can you find out what charging loss you experience every time you plug in the charging cable into your vehicle?

You can use the data provided by reputable testing organizations.

For instance, ADAC has conducted an ecotest using the same 22 kW wallbox (AC) and the same ambient conditions (23°C) to discover the charging loss. The charging losses turned out to be considerable.

For instance, the result shows that 125.2 kWh must be charged to fill the 105 kWh battery of the BMW iX. The situation is no better in the case of the less expensive Jaguar i-Pace - 100.8 to 90 kWh.

 

[Craigins]

I get what you're saying, but I have never noticed increased cabin temperatures for any reason other than direct sunlight. Especially at level 2 charging, there shouldn't be anywhere near enough heat generated that the BMS can't manage it to the point it heats the cabin.

A would agree with the recommendation to put in a ticket.

How big is your garage, and how insulated?

My cabin is always reading 80-90 degrees after charging for awhile and the garage is warm as well.

If you have a larger/well ventilated garage you may not notice it.

 

[godfodder0901]

We don't have enough information about the BMS to know what it is doing. But here's a simple thought experiment based on the article link I posted at the bottom.

If you charge overnight to add 100 kWh to the battery, due to efficiency loss, it's going to draw 110 to 120 kWh total power to do so, resulting in 10 to 20 kWh loss as heat. That's a fair amount of heat - that's very roughly equal to running a Pelonis 1500w ceramic furnace continuously while charging. That heat has to go somewhere. In a still air garage with the cabin sitting over top the batteries, and the batteries and inverter thermally bonded to the vehicle, the cabin is a sealed heating chamber.

In the end, only Rivian can tell us if this is "normal" but I suspect it is.

But how can you find out what charging loss you experience every time you plug in the charging cable into your vehicle?

You can use the data provided by reputable testing organizations.

For instance, ADAC has conducted an ecotest using the same 22 kW wallbox (AC) and the same ambient conditions (23°C) to discover the charging loss. The charging losses turned out to be considerable.

For instance, the result shows that 125.2 kWh must be charged to fill the 105 kWh battery of the BMW iX. The situation is no better in the case of the less expensive Jaguar i-Pace - 100.8 to 90 kWh.

There were reports that Rivian likes to keep their batteries as close to 70 degrees as possible. And we do know that the thermals are actively managed by the vehicle while DCFC and level 2 charging.

If this increased cabin temp were normal, then why aren't more people seeing this? Do his experiences match your own? OP didn't put specifics, but his charging session was likely over for hours before he noticed the high cabin temp. My own observations do not support this notion of normalcy. I plug in, and remain plugged in all night, every day. I have no TOU discounts so I have no charging schedule set. I have gotten in the truck at varying times in the charge cycle; at the beginning of the charge, interrupted charges to run errands, and I've gotten in right after the charge cycle ended. My temperate climate and insulated garage mean that the ambient is almost always in the mid 60's, and my cabin is ALWAYS in the low to mid 70's. If your assumptions were accurate, that would mean my cabin should be closer to 105 degrees depending on charging status.

 

[PoorDick]

It's a standard 20 x 20 garage, but the issue is that the heat has never happened like this since March of 2022. 18 months of following the ABC mantra (Always Be Charging) and I've never had the heat issue inside the cabin until now, so obviously something has changed. I've put in a ticket but it will be at least a week before I can get it to the service center. Just received the recall notice for the halfshaft splines and they can't fit me in until then.

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