Battery Leak

[Ogre]

I really appreciate the super helpful info shared in quite digestible fashion. That brings another question: This probably wouldn't apply to CT but on current Teslas, would replacing the 12V battery with a lithium ion battery require any software adjustment so that main pack does not over charge it? or these batteries are responsible to protect themselves with their own circuits? and simply replacing the old battery with 12V lithium ion is safe?

I know this isn’t an answer to your question… but even so.

Elon Musk recently described the Cybertruck as “Intentionally An Insane Technology Bandwagon”. This makes me think Tesla is going to cram as much new stuff into it as they can see possible. My assumption is if you’ve heard Musk talk about it… it’ll happen.

That means a 48v lithium ion battery is highly likely.

As for existing owners and their dinosaur cars with “12v so called batteries”… Tesla has hinted a Lithium Ion upgrade part is in the works for those to. Not sure when… but who cares, we’ll have 48 volts before they figure that out.

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[Diehard]

I know this isn’t an answer to your question… but even so.

Elon Musk recently described the Cybertruck as “Intentionally An Insane Technology Bandwagon”. This makes me think Tesla is going to cram as much new stuff into it as they can see possible. My assumption is if you’ve heard Musk talk about it… it’ll happen.

That means a 48v lithium ion battery is highly likely.

As for existing owners and their dinosaur cars with “12v so called batteries”… Tesla has hinted a Lithium Ion upgrade part is in the works for those to. Not sure when… but who cares, we’ll have 48 volts before they figure that out.

That was my sneaky way of asking if I end up with one of the other dinosaurs (Rivian or Lightning) can I fix them safely? I already have replaced batteries for a motorcycle and an scooter with Lithium Inon and loved the results; nothing blew up and they have performed very nicely over time. But they are old school and don't have too many smart parts in them to get mad at each other.

 

[CyberGus]

Tesla now uses a 12v lithium pack, with its own circuitry and a unique connector.

 

[Ogre]

That was my sneaky way of asking if I end up with one of the other dinosaurs (Rivian or Lightning) can I fix them safely? I already have replaced batteries for a motorcycle and an scooter with Lithium Inon and loved the results; nothing blew up and they have performed very nicely over time. But they are old school and don't have too many smart parts in them to get mad at each other.

There are drop in lithium ion batteries for RVs (and regular cars I think). If it uses a normal 12v system should be fine. I’m not sure what the 12v system in older Model 3/Ys is like.

 

[kraal]

For any battery:
V=Vemf-IRi
So, because of internal resistance (Ri), the batteries will totally drain for t->infinite (sometimes it is a very short infinite!)

 

[Crissa]

There's two basic things that are the major sources of charge loss:

1. Cell rebound
2. Vampire loads

Cell rebound is the natural affect of the charge state un-fixing itself. As the voltage from charging is released, not all of the electrons stay fixed to one side. They naturally want to wander back to the other. The amount of this varies by cell chemistry, temperature, temperature variation, etc.

This is most apparent right after a charge, but tapers down with more time. So my bike will lose a percent a day for the first week, then... Nada. Doesn't matter if it's at 90% or 30%. Although, depending upon where you left it, it might just 'phantom charge' instead of 'phantom drain'.

This can also make it 'seem' like you've lost charge without actually doing so - like if the battery gets really cold. Then it looks like it's lost charge, but it really hasn't. It just needs to heat up to release it. But internal resistance or battery heating can use up your charge to heat up the battery and give you access to the remainder. But just sitting in the sun and warming up will do the same. (Do that in a hot summer and a different kind of charge loss - capacity loss - happens)

That brings us to the vampire loads. Things like lights, security systems, clocks, battery management, thermal management, communication... All these things are a drain. They're controlled by what you're having it do. Most EVs will fall into a storage mode after a period of inactivity - even mine - and cut these loads down to a minimum.

At any rate, both of these effects vary wildly by cell type, ambient temperatures, electronics... so it's hard to say without doing any empirical experiments what any particular EV will do.

-Crissa

 

[Tinker71]

I know this isn’t an answer to your question… but even so.

Elon Musk recently described the Cybertruck as “Intentionally An Insane Technology Bandwagon”. This makes me think Tesla is going to cram as much new stuff into it as they can see possible. My assumption is if you’ve heard Musk talk about it… it’ll happen.

That means a 48v lithium ion battery is highly likely.

As for existing owners and their dinosaur cars with “12v so called batteries”… Tesla has hinted a Lithium Ion upgrade part is in the works for those to. Not sure when… but who cares, we’ll have 48 volts before they figure that out.

I hope you are right. That might also be an efficiency gain with smaller wires etc. What do you think the odds of the whole vehicle going to 800V. That many batteries in series makes me nervous, one bad 4680 would be worse at 800V than 400V correct?

 

[Diehard]

The amount of this varies by cell chemistry, temperature, temperature variation, etc.

This can also make it 'seem' like you've lost charge without actually doing so - like if the battery gets really cold. Then it looks like it's lost charge, but it really hasn't. It just needs to heat up to release it. But internal resistance or battery heating can use up your charge to heat up the battery and give you access to the remainder. But just sitting in the sun and warming up will do the same. (Do that in a hot summer and a different kind of charge loss - capacity loss - happens)

The problem with giving great info is that I want more.

1 - I don’t have a garage. Does keeping CT outside in winter vs in a garage means only using more energy to warm up the battery when I want to use the vehicle? Or it has to constantly use energy to keep a minimum temp while sitting? Do you keep your bike outside in winter?

2 - If for some reason the System can not take care of the battery in the cold, does that mean permanent damage or capacity loss? Or heat is the only enemy?

 

[Tinker71]

The problem with giving great info is that I want more.

1 - I don’t have a garage. Does keeping CT outside in winter vs in a garage means only using more energy to warm up the battery when I want to use the vehicle? Or it has to constantly use energy to keep a minimum temp while sitting? Do you keep your bike outside in winter?

2 - If for some reason the System can not take care of the battery in the cold, does that mean permanent damage or capacity loss? Or heat is the only enemy?

My understanding is charging while cold is bad. <45F degrees. So in theory if you let your battery pack go to 0F degree it would be fine as long as you didn't charge them until they warmed up. I am not sure how you would do that other than getting in a heated garage.

This is assuming they are cold and charged. I think you will just want to keep your truck plugged in. If your charger is set to turn off at 70% state of charge, just leave it plugged in every night in the winter.

 

[Diehard]

My understanding is charging while cold is bad. <45F degrees. So in theory if you let your battery pack go to 0F degree it would be fine as long as you didn't charge them until they warmed up. I am not sure how you would do that other than getting in a heated garage.

This is assuming they are cold and charged. I think you will just want to keep your truck plugged in. If your charger is set to turn off at 70% state of charge, just leave it plugged in every night in the winter.

Are you saying if I leave it unplugged, the battery gets cold and when I plug it in, the system wouldn’t heat up the battery first before starting to charge? And if I leave it plugged in, it always uses power to keep the battery warm? That sounds like such a waste and like I should either get a garage or an ICE. Did I misunderstand how it works?

 

[Klaxon]

I really appreciate the super helpful info shared in quite digestible fashion. That brings another question: This probably wouldn't apply to CT but on current Teslas, would replacing the 12V battery with a lithium ion battery require any software adjustment so that main pack does not over charge it? or these batteries are responsible to protect themselves with their own circuits? and simply replacing the old battery with 12V lithium ion is safe?

Litium batteries have a bit different charging pattern than lead acid batteries. They have specialized charge controlling chips. Probably simple swapping may not be recommended

 

[Tinker71]

Are you saying if I leave it unplugged, the battery gets cold and when I plug it in, the system wouldn’t heat up the battery first before starting to charge? And if I leave it plugged in, it always uses power to keep the battery warm? That sounds like such a waste and like I should either get a garage or an ICE. Did I misunderstand how it works?

No the vehicle will maintain a healthy temperature for the battery to accept a charge at the expense of range.

I don't know why you would ever want to allow your batteries to go cold. Maybe a long term parking situation, but they will still drain slowly so you would not want them to go below 10%.

I don't know the optimal temp the vehicles keep the batteries at (maybe 50F), but they are protected from wind and moisture, with a little insulation. I would guess 200 watts or so to keep them warm on a 20F night.

 

[Tinker71]

No the vehicle will maintain a healthy temperature for the battery to accept a charge at the expense of range.

I don't know why you would ever want to allow your batteries to go cold. Maybe a long term parking situation, but they will still drain slowly so you would not want them to go below 10%.

I don't know the optimal temp the vehicles keep the batteries at (maybe 50F), but they are protected from wind and moisture, with a little insulation. I would guess 200 watts or so to keep them warm on a 20F night.

I think chargers are really smart now days as well. They will start charging slowly which heats the battery and then increase the charge when conditions are optimal.

My DIY EV bus was not getting driven much in the winter. I wanted to keep it outside but not destroy the batteries. My 26kWhr battery pack is stuffed in the back. I insulated the battery compartment and wrapped some heat tape around some copper pipe and placed that mess under the batteries. I monitored the temperature and was able to keep the batteries from freezing when in the lower 20s. This winter I am just going to take the batteries out and park it outside. It is too much to worry about.

 

[Diehard]

No the vehicle will maintain a healthy temperature for the battery to accept a charge at the expense of range.

I don't know why you would ever want to allow your batteries to go cold. Maybe a long term parking situation, but they will still drain slowly so you would not want them to go below 10%.

I don't know the optimal temp the vehicles keep the batteries at (maybe 50F), but they are protected from wind and moisture, with a little insulation. I would guess 200 watts or so to keep them warm on a 20F night.

For a tool which it’s primary function is to move, it is hard to imagine going green by using energy for just sitting there. I guess it is all matter of how much energy it waste. Any Canadian or New England EV owners in the house? What is your real life experience, keeping your battery warm in winter? Any idea how much extra juice you use in winter to keep your battery warm?

My DIY EV bus was not getting driven much in the winter. I wanted to keep it outside but not destroy the batteries. My 26kWhr battery pack is stuffed in the back. I insulated the battery compartment and wrapped some heat tape around some copper pipe and placed that mess under the batteries. I monitored the temperature and was able to keep the batteries from freezing when in the lower 20s. This winter I am just going to take the batteries out and park it outside. It is too much to worry about.

Impressive. It is easy to bring my lawnmower battery in for winter but CT battery pack is a different story.

 

[Tinker71]

For a tool which it’s primary function is to move, it is hard to imagine going green by using energy for just sitting there. I guess it is all matter of how much energy it waste. Any Canadian or New England EV owners in the house? What is your real life experience, keeping your battery warm in winter? Any idea how much extra juice you use in winter to keep your battery warm?



Impressive. It is easy to bring my lawnmower battery in for winter but CT battery pack is a different story.

In comparison an ICE car needs to warm up before you can really defrost. Lots of pollution in the first couple minutes and that energy is mostly wasted.

The CT in your driveway will have a core temp of 50F. It would be interesting to see what defrost faster, your Oldmobile or the CT. Stick around and tell us.

I am pumped for the low guilt precondition function. I am going to drive you in 5 minutes. Get ready.

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