Mike818

sorry if this has been answered, but do these batteries have some kind of active thermal management? AFAIK LFP does not do well below freezing, and seeing how this is OEM I am curious how they are pulling it (or not) off.

KM20Turbo

I don’t know the answer to your question but that battery is used on all Canadian 992’s. I assumed that was related to the climate.

Mike818

Huh... that leads me to believe this battery is either very interesting or very poorly chosen for the application. I've never heard of an LFP battery that can take a charge below freezing so I'm definitely interested to learn more about what is going on with this.

malba2366

There is no active thermal management system for the Lithium starter battery. I am not sure why they decided to fit it in all Canadian cars.

BondJ

Lithium is no worse than gel in cold weather. Just don’t charge them outside if freezing cold

Stephen Shi

It's probably not lithium Ion but LiFePo4, which is safer and can work in lower temp. than LiOn battery.

Mike818

right? Real head scratcher

No they are worse, if you charge below freezing it will damage the cell. Typically as soon as the engine fires the alternator will start pushing current into the battery.



LFP aka LiFePo4 aka Lithium Iron phosphate is more stable, but still has a minimum charging temperature of freezing. The only chemistry I am familiar with that is good for low temps is LTO - Lithium Titanate.

Mademusc

My cup runneth over with...

Antigravity

I'm sure the Porsche Lithium Battery made by A123 Systems has Thermal Protections... you would not neccesarily call it management because it does not manage the temperature so to speak, but it will have a protection system in place for high and low temperature cut-off protections. A123 is a high end battery manufacturer and would definately be putting in thermal protections for high and low temps. Another fact is that just because it is freezing outside does not mean your Lithium Battery will be frozen, it take a decent amount of time to freeze a Automotive sized Lithium Battery, but addtionally if the Battery is discharging or being charged it will also not be to the point of freezing since both of these actions will have current going into or coming out of the battery which will warm the cells and prevent them from freezing. Lastly, I assume Porsche is thinking that most Customers will not be leaving thier very expensive sports cars in well below sub freezing weather for a long enough time to freeze their Lithium Battery.... this is just an assumption on my part... so that if someone is paying well north of the 100k for thier sports cars they have income levels that would indicate they have a garage or storage area of some sort for the vehicle, that would not be in direct sub freezing temps for the most part... and the lithium can handle sub freezing for a little while, and they expect it to be on a charger... so they feel they are safe from that.

I have taken several Cars up to going snowboarding for a few weeks and we are in sub freezing temps for several weeks, but never experianced a frozen battery.... and we aren't driving daily, sometimes the cars will sit several days. We take up a Diesel Truck and also a SUV and both have no issues whatsoever on our long term stays.

Mike818

Thanks for chiming in. Typically you do see a low temp cutoff for LFP, but in a starting battery that means it won't work below freezing. That's not really acceptable in a starting battery. So other than that it sounds like we are just doing a lot of hoping. Hoping the battery doesn't actually freeze, hoping that the car is kept in temperature controlled environment, hoping internal resistive heating will uniformly warm the battery up to operating temp, no matter the starting temp, etc.. Not really confidence inspiring to be honest. It hit -1F or 33 below freezing in Tahoe during my trip this last winter.

Max141949

I was wondering if you could help me with my situation? I have a 2020 992 with a lithium battery. I have successfully stored this car car for the winter using the Porsche battery maintainer.
I have recently moved to a condo with heated garage and NOPOWER for my maintainer.I take the insurance off and the roads are full of snow therefore no topping up the battery.
Was wondering what your thoughts are about a battery power pac(EcoFlow) to power the maintainer and thus allow me to plug into my car?
I realize that I would have to do this periodically,
Any suggestions would be appreciated! M

KM20Turbo

If you’re not able to drive it, wouldn’t it be cheaper to put it in winter storage? Or pull the battery and put it on a battery maintainer in your home.

Stephen Shi

it’s exactly what i do every winter, bring the battery upstairs and charge it at home. It’s lighter battery so much easier to do so. Also, i have parked the car for almost a month now and the battery is still at 90% charged. It’s the lifepo battery btw.

Max141949

First of all thanks for getting back to me.
Regarding pulling the battery will there be any problems in the spring when I put the battery back in? Will all the settings be the same or will I have to bring it in for service. Thanks, M

Stephen Shi

you may lose some settings such as long press window button to automatically send window all the way down. Nothing big will happen to the car.