Isn't one of the problems getting a Li-ion 12V battery that will be happy at -20F? Lead-acid is good for that.
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12v battery issue, Tesla unsatisfactory response
- Thread starter Tjhappel
- Start date
android04
Active Member
LiFePO4 is good for that too. They have reduced capacity at colder temps (just like lead acid, but at higher cold temps) but you don't need a lot of battery capacity to turn over an engine like you would in an ICE car. Ohmmu and EarthX LiFePO4 batteries (two of the options to replace the OEM Model 3 battery) have been tested in sub-zero temps and in Canada with no issues.
Daniel in SD
(supervised)
I'm not a battery expert but I think they only lose available capacity at cold temperatures? It's not clear to me why you couldn't put the 12V battery in the main pack so it would benefit from the thermal management.
One issue I can think of is that Li-Ion batteries might not have the proper cell voltage for 12V automotive parts. At very cold temperatures the voltage drops to 3.3V under load which would only be 9.9V for three series cells, might be out of spec for airbags or what not. Part of the issue could be that Tesla uses many of same parts as everyone else and they're all designed for lead acid voltage ranges.
Just for some concern trolling, I wonder if LiFePO4 batteries would really work to maintain power steering and airbags if the main pack blows up while driving in extremely cold weather? It doesn't take much current to "start" a Tesla, high current from the 12V battery is only used when something goes wrong.
sure all these batteries have reduced capacity, but I thought the real problem was charging in the cold... which ruins a Li-ion, no?
Pic? I have mine in the cabin since the windows supposedly auto roll down
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this is a key issue. Most tow truck drivers won't know how to do "surgery" to get the battery. I wonder if there's a way to OTA fix this to auto-unlock the hood if the 12 V dies (just like the windows dropping).
and to the naysayers about security stop storing valuables in the frunk!
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There has to be a better way . . . there are far too many "hacks" in how to solve this problem.
These 12-volt nightmares need to be in "past" chapter of Tesla's history ASAP.
Fix it Elon; this ain't rocket science!
These 12-volt nightmares need to be in "past" chapter of Tesla's history ASAP.
Fix it Elon; this ain't rocket science!
My model 3 has a large rectangle door on the bottom. I don't have a tow hitch it's just a lot of empty space when I open the door. I think they started putting the doors in end of 2019 builds.
The jump starter isn't sold anymore. It was a gift. It looks like all the other small jump starters. It came with a case that hold it and the clamps. Nothing amazing there's a lot of them on Amazon.
The door is a good place to hide things if you have it.
I didn't know about this. If that's the case glove box makes more sense.
How does it know to roll the windows down? Some people say their battery died while the car was asleep and they didn't even get a notice. If it knew the battery was low wouldn't it just charge it continuously.
RayK
Active Member
Assuming that the windows do roll down when the 12V dies (I really don't like this: what happens if it's raining?), how are you going to get into the glovebox? You do know that it opens with a button on the screen? In an accident it's supposed to automatically open but I don't think it's going to do the same thing when 12V power is lost.
android04
Active Member
The Ohmmu and EarthX batteries have a BMS to preserve the battery. It will not allow charging if below freezing. Just drawing power from the battery will cause it to warm up. Also, the BMS has resistors to balance the cells and probably uses that to warm them up too. I would have no qualms about using either the Ohmmu or EarthX batteries in my Model 3. My OEM battery is still going strong after 2.5 years and 47,500 miles though.
I pulled my battery out yesterday just to see what all the fuss is about. What I learned is it's the same as every other car battery I've pulled out except it's tiny. You can take this thing out in 5mins assuming you can get to it.
Don't pay tesla $200 to do this. Just buy the battery for $80 and put it in.
Don't pay tesla $200 to do this. Just buy the battery for $80 and put it in.
the battery doesn't cost $80... you forgot to add a 1 before that...
you also need to disconnect main battery pack under rear seat on passenger side... so "just like every other car"
Ok if you decide to do that it takes 5mins 5seconds.
I am not sure why that is needed. If the battery already died it shouldn't even matter. I've seen videos of people doing it with and without. When you disconnect the 12v you hear the high voltage disconnect activate. If you have power.
When you unplug that connector in the back you hear the high voltage disconnect activate if you have power.
Someone posted in another thread that tesla sold them the 12v battery for $80.
Yes for sure. When I built my RV I had to use AGM batteries since lithium ion have protectiona to prevent them charging when too cold.
Well, almost. There are a couple of differences. The Tesla battery is an AGM, deep cycle battery. This battery class is not the same as the typical ICE battery which is designed to provide a huge amount of cranking amperage to start the car.
But as long as you make sure that you get a deep cycle AGM battery of the correct size, you should be good to go.
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