Using your Cybertruck as a home charger -- battery life concerns?

[dalton108]

My ranch house was built in 1969, and though it’s been remodeled over the years, its electrical panel is overloaded. Until I can get this rectified, I’m unable to install the two wall chargers I brought with me from my previous home.

In the meantime, we need to rely on Superchargers as a routine backup to keep our small fleet of 3 Teslas going. Fortunately, there are two 250 kW chargers within about two miles, both east and west of my home, so it’s not too bad—though the situation is less than ideal. There’s nothing like waking up to a fully charged car in your garage or driveway (1-3 mph on 120v is NOT IT!). So …

Yesterday, I charged my CB to 95%, planning to finally get out with my ’21 TigerMoth trailer and see what kind of range I could get on a test run. The day got away from me, and I had to scrub the mission. So now, I’m sitting with my Cybertruck at 95%, which I know isn’t great for the battery, and I didn’t want to drive it just to drain it.

At this point, I realized my wife’s Tesla needed a charge, and my Plaid needed one as well, so I decided to charge both from the CB. This worked great—I killed three birds with one stone. MY charged from 60% to 80% at 28 mph (1hr 20mins), and the MS Plaid charged from 51% to 80% at about 23 mph (3hrs or so). The CB went from 95% to 55% state of charge. Super!

Now, my question is this: I know that we can do this, and I’ve watched just about every Cybertruck video on YouTube (Kyle, Zak, Jesse, and everyone in between) showing what can be done, but I haven’t seen anyone discuss whether using your Cybertruck as a charger impacts battery longevity. Is there any reason I should be concerned about making this a routine practice—at least until I get upgraded panels at my house? (Because one trip to the Supercharger is certainly better than three!). Thoughts?

*The images are screenshots from the Stats app.

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[mongo]

My ranch house was built in 1969, and though it’s been remodeled over the years, its electrical panel is overloaded. Until I can get this rectified, I’m unable to install the two wall chargers I brought with me from my previous home.

In the meantime, we need to rely on Superchargers as a routine backup to keep our small fleet of 3 Teslas going. Fortunately, there are two 250 kW chargers within about two miles, both east and west of my home, so it’s not too bad—though the situation is less than ideal. There’s nothing like waking up to a fully charged car in your garage or driveway (1-3 mph on 120v is NOT IT!). So …

Yesterday, I charged my CB to 95%, planning to finally get out with my ’21 TigerMoth trailer and see what kind of range I could get on a test run. The day got away from me, and I had to scrub the mission. So now, I’m sitting with my Cybertruck at 95%, which I know isn’t great for the battery, and I didn’t want to drive it just to drain it.

At this point, I realized my wife’s Tesla needed a charge, and my Plaid needed one as well, so I decided to charge both from the CB. This worked great—I killed three birds with one stone. MY charged from 60% to 80% at 28 mph (1hr 20mins), and the MS Plaid charged from 51% to 80% at about 23 mph (3hrs or so). The CB went from 95% to 55% state of charge. Super!

Now, my question is this: I know that we can do this, and I’ve watched just about every Cybertruck video on YouTube (Kyle, Zak, Jesse, and everyone in between) showing what can be done, but I haven’t seen anyone discuss whether using your Cybertruck as a charger impacts battery longevity. Is there any reason I should be concerned about making this a routine practice—at least until I get upgraded panels at my house? (Because one trip to the Supercharger is certainly better than three!). Thoughts?

*The images are screenshots from the Stats app.

,
Battery cycles are battery cycles whether a result of driving or charging other cars.
That said, the 32A mobile connector charge rate is only 1/3 of the power draw you get when driving 60 MPH, so it is more gentle on the discharge side of things.
Additionally, the warranty calls out an exclusion for "Using the vehicle as a permanent or long-term power source with signs of unreasonably high energy throughput that may be inconsistent with the mileage driven;"

Your current house power doesn't support use of the mobile connector at 240V?

 

[dalton108]

,
Battery cycles are battery cycles whether a result of driving or charging other cars.
That said, the 32A mobile connector charge rate is only 1/3 of the power draw you get when driving 60 MPH, so it is more gentle on the discharge side of things.
Additionally, the warranty calls out an exclusion for "Using the vehicle as a permanent or long-term power source with signs of unreasonably high energy throughput that may be inconsistent with the mileage driven;"

Your current house power doesn't support use of the mobile connector at 240V?

Thanks a lot! Kind of what I thought about the battery cycles. I really reviewed the warranty carefully, so thanks for that important catch.


As far as the 240v, the only 240 outlet is inside of the house where the laundry hook up is and since it’s not in or really near our garage there’s no convenient way to decouple the dryer or put in a splitter and run 240 to reach any of the vehicles.

Considered running something from the house across the breezeway through the garage off of the same circuit but it wouldn’t be cheap even with my cut rate handyman and it would only be an interim solution.

 

[flyinglow]

There has been a lot of research showing that charging to 65% or less will extend battery life significantly. I wish I still had the link but, if my memory serves me correctly, there was one study in Australia that showed the kind of lithium ion cells used in the Cybertruck would last 6500 cycles charged to 65% vs 3000 cycles for 80%. Don't worry about the number of cycles quoted since we seldom fully cycle our vehicle batteries. Instead, what is important is that charging to a lower level dramatically extends your battery life.

Based on all of that, consider the the number of miles you expect to travel and charge enough to give you those miles plus whatever buffer you are comfortable with. For example: if you drive 50 miles a day and are averaging 2.5 m/kWh, that means you need 20 kWh plus, conservatively, a 10% SOC buffer of 12 kWh for a total of 32 kWh. That is roughly 30% SOC so you would only charge the battery to 30% on a daily basis and only charge higher when you expect to travel a longer distance.

Now, 30% is probably way more conservative than most of us will feel the need to be in terms of battery life. However, you can see that you can comfortably make 50 or 65% your daily "top up" charge level and avoid significant battery deterioration.

 

[Woodrick]

My ranch house was built in 1969, and though it’s been remodeled over the years, its electrical panel is overloaded. Until I can get this rectified, I’m unable to install the two wall chargers I brought with me from my previous home.

In the meantime, we need to rely on Superchargers as a routine backup to keep our small fleet of 3 Teslas going. Fortunately, there are two 250 kW chargers within about two miles, both east and west of my home, so it’s not too bad—though the situation is less than ideal. There’s nothing like waking up to a fully charged car in your garage or driveway (1-3 mph on 120v is NOT IT!). So …

Yesterday, I charged my CB to 95%, planning to finally get out with my ’21 TigerMoth trailer and see what kind of range I could get on a test run. The day got away from me, and I had to scrub the mission. So now, I’m sitting with my Cybertruck at 95%, which I know isn’t great for the battery, and I didn’t want to drive it just to drain it.

At this point, I realized my wife’s Tesla needed a charge, and my Plaid needed one as well, so I decided to charge both from the CB. This worked great—I killed three birds with one stone. MY charged from 60% to 80% at 28 mph (1hr 20mins), and the MS Plaid charged from 51% to 80% at about 23 mph (3hrs or so). The CB went from 95% to 55% state of charge. Super!

Now, my question is this: I know that we can do this, and I’ve watched just about every Cybertruck video on YouTube (Kyle, Zak, Jesse, and everyone in between) showing what can be done, but I haven’t seen anyone discuss whether using your Cybertruck as a charger impacts battery longevity. Is there any reason I should be concerned about making this a routine practice—at least until I get upgraded panels at my house? (Because one trip to the Supercharger is certainly better than three!). Thoughts?

*The images are screenshots from the Stats app.

The Model Y and to a slightly lesser extent, the Model S, will happily charge off of a 120V 15A outlet (as long as there are no other major loads on it).
I've been doing that with my Model 3 and Model Y by alternating them plugging into the 120V outlet for a few years. The Model Y will get about 60 miles in 12 hours.
You'll then be using much cheaper energy than Supercharger rates.
The Cybertruck charges much slower, because of the fact that it uses basically twice the power to go a mile.

It would be much better if you just took each vehicle to the Supercharger when it needs to be filled and not charge them from the Cybertruck (if you can't charge off of 120V).
If you keep the vehicles charged down low, below 50-60%, then you should have plenty of range to do what you probably need to do, but as you come back home, only a 5 minute stop will add about 50 miles to the cars.

 

[DaBagBoy]

Similar issue -
I ended up allowing a carpenter to store his saws and stuff in my garage while I was away at work with the Model Y. When I got home I realized the cord couldn't reach the garage wall charger with the Y in the driveway.

Ended up charging the Y from the CT for 3 days while charging the CT after I left for work in the Y.

As others have said that will complete a battery cycle on the CT, but I think I'll be OK with 3,000-6,000 charge cycles.

But I respectfully disagree with @Woodrick as Supercharger charging will wear out the batter much more quickly than 48amp charging from the garage or 30amp charging in the driveway.

 

[Woodrick]

But I respectfully disagree with @Woodrick as Supercharger charging will wear out the batter much more quickly than 48amp charging from the garage or 30amp charging in the driveway.

Supercharging wearing out the battery has been completely disproved.

Matter of fact, the cars with the most mileage are essentially Supercharged multiple times daily, often to 100%.

Even Tesla has indicated that Supercharging does absolutely no harm to the battery.

 

[DaBagBoy]

Supercharging wearing out the battery has been completely disproved.

Matter of fact, the cars with the most mileage are essentially Supercharged multiple times daily, often to 100%.

Even Tesla has indicated that Supercharging does absolutely no harm to the battery.

OK - TBH I don't really know nor have the data myself.....so I asked Grok -

Does a Tesla battery degrade more with supercharging or Level 2 charging?


The degradation of a Tesla battery can be influenced by various factors, including charging habits, but it's primarily about how often and how deeply the battery is charged, rather than the specific method of charging (Supercharging vs. Level 2).
Here's a breakdown:

1. **Frequency and Depth of Charge**: - **Supercharging**: Typically, Superchargers are used for quick top-ups, which means you might not charge to 100% as often. However, if you frequently supercharge to high percentages, especially from low levels, this can contribute to battery degradation over time due to the heat generated and the stress on the battery. - **Level 2 Charging**: Usually done at home or work, often overnight or for long periods. Charging to 100% regularly, regardless of the charging speed, can lead to degradation. However, Level 2 chargers generate less heat during charging, which might be gentler on the battery in terms of thermal stress.

2. **Heat**: - Both types of charging can produce heat, but Superchargers deliver a much higher current, thus generating more heat. Heat is one of the primary factors in battery degradation. Tesla's battery management system (BMS) is designed to mitigate this by limiting supercharge speeds in certain conditions, but heat remains a concern.

3. **Tesla's Software and Battery Chemistry**: - Modern Tesla vehicles have software that optimizes charging patterns to minimize degradation. For instance, it might slow down the charge rate as the battery approaches full to reduce stress. - Tesla uses different battery chemistries over time, and newer chemistries (like those in the Model 3 and Y) are designed to handle more charge cycles and potentially less degradation compared to older models.

4. **Usage Patterns**: - How the car is driven also matters. High-speed driving, frequent fast acceleration, and heavy use of features like Autopilot can contribute to battery wear, independent of charging method.

**In summary**: - **Supercharging**:
More frequent supercharging, especially to high percentages from low, can contribute more to degradation due to thermal and electrical stress. However, occasional use is generally not a major concern. - **Level 2 Charging**: If you frequently charge to 100% with Level 2, this can also lead to degradation, though typically at a slower rate due to less heat generation.

**Best Practices**: - Avoid charging to 100% unless necessary. Keeping the battery between 20% and 80% can significantly extend its life. - Use Supercharging for long trips or when necessary, not as the primary charging method. - For daily charging, especially overnight, Level 2 charging at home is generally better for battery health. Tesla advises that their batteries are designed for longevity and can handle many charge cycles, but like any battery, how it's treated impacts its lifespan. If you're concerned about battery health, balancing between charging methods and keeping an eye on battery temperature and charge levels is key.

 

[eswimm]

I'm actually surprised that Tesla's battery warranty on the CT doesn't specify a ceiling for power delivery vs. driving. The reality is that the 30% degradation coverage is just there to make people feel better. There's almost no conditions where you would experience 30% degradation in the warranty period and not also experience a covered battery failure.

 

[Woodrick]

OK - TBH I don't really know nor have the data myself.....so I asked Grok -

Here's one source.
Tesla battery longevity not affected by frequent Supercharging, study says | Electrek

 

[REM]

Good questions, and ultimately the best answer is going to be charge and discharge according to your actual needs or convenience since the system is designed to be extremely robust.

I don't think you will see any measurable degradation over the next few years (or maybe even decade) if you use your CT to infrequently charge another EV or run backup circuits in your house. The best thing you can do for your battery is get into the habit of trying to keep your SoC near 50% most of the time.

But! If you need to charge up to 100% while traveling or when a bad storm is approaching, then absolutely do it! You won't harm it. Most people cause degradation when they too frequently allow full or (near full) discharge or overcharge (charging up to 80% or more every day when they don't actually need that amount).

How quickly can you get that circuit installed? We talking couple of weeks/months, or more than half a year?

 

[dalton108]

Good questions, and ultimately the best answer is going to be charge and discharge according to your actual needs or convenience since the system is designed to be extremely robust.

I don't think you will see any measurable degradation over the next few years (or maybe even decade) if you use your CT to infrequently charge another EV or run backup circuits in your house. The best thing you can do for your battery is get into the habit of trying to keep your SoC near 50% most of the time.

But! If you need to charge up to 100% while traveling or when a bad storm is approaching, then absolutely do it! You won't harm it. Most people cause degradation when they too frequently allow full or (near full) discharge or overcharge (charging up to 80% or more every day when they don't actually need that amount).

How quickly can you get that circuit installed? We talking couple of weeks/months, or more than half a year?

it’s been tedious I had a couple of fall starts with contractors that didn’t follow through and there has been a well known backlog and getting permits. And frankly I haven’t been all that aggressive about it but my house is absolutely overloaded and a whole new panel is required. So the answer to your question is I expect to have it done within the next six months.

I’m not gonna make a daily habit of it my wife usually charges her own car as needed and we plug-in at home but even on her model Y we get no more than 3 mph charging so that’s enough to top off for her commute which is about 4 miles round-trip and my commute is only a mile round-trip. I get to choose where my office is, and I always keep it close to my house. ? (I can literally see my house from certain angles in our tower and the view from the other side ain’t too bad either as you can see.)

I generally keep my cars between 80% and 50%. I do have to remind my wife to not let her car go down to below 20% on a fairly regular basis. But I keep a close eye on that situation, as well.

this thread has produced some great feedback and I’m really glad that I asked the question. Bear in mind though this was just a unique circumstance where I charged up the CB to way more than I needed it because I was planning on doing a towing test and then needed a way to get rid of all those extra electrons.

it just got me thinking about could this be a time saver and I think I might do it once in a blue moon if the circumstances call for it.

Much obliged!

 

[dalton108]

Forgot attach image, again

 

[REM]

it’s been tedious I had a couple of fall starts with contractors that didn’t follow through and there has been a well known backlog and getting permits. And frankly I haven’t been all that aggressive about it but my house is absolutely overloaded and a whole new panel is required. So the answer to your question is I expect to have it done within the next six months.

I’m not gonna make a daily habit of it my wife usually charges her own car as needed and we plug-in at home but even on her model Y we get no more than 3 mph charging so that’s enough to top off for her commute which is about 4 miles round-trip and my commute is only a mile round-trip. I get to choose where my office is, and I always keep it close to my house. ? (I can literally see my house from certain angles in our tower and the view from the other side ain’t too bad either as you can see.)

I generally keep my cars between 80% and 50%. I do have to remind my wife to not let her car go down to below 20% on a fairly regular basis. But I keep a close eye on that situation, as well.

this thread has produced some great feedback and I’m really glad that I asked the question. Bear in mind though this was just a unique circumstance where I charged up the CB to way more than I needed it because I was planning on doing a towing test and then needed a way to get rid of all those extra electrons.

it just got me thinking about could this be a time saver and I think I might do it once in a blue moon if the circumstances call for it.

Much obliged!

I suppose you live in the city, or at least suburb, but maybe the power company can run a temporary connection for you while your panel rework is quoted and built out?

I live in the countryside, so such a thing would be a simple phone call away and they would be out probably the next day or two.

Do you have the "PlugShare" app? It has been tremendously helpful over the past few years with finding alternative charging opportunities. Maybe there is one very close by that you can use in the meantime? Can you not charge at work? Check the app, you may be surprised how close a free charging site is located.

 

[Woodrick]

it’s been tedious I had a couple of fall starts with contractors that didn’t follow through and there has been a well known backlog and getting permits. And frankly I haven’t been all that aggressive about it but my house is absolutely overloaded and a whole new panel is required. So the answer to your question is I expect to have it done within the next six months.

I’m not gonna make a daily habit of it my wife usually charges her own car as needed and we plug-in at home but even on her model Y we get no more than 3 mph charging so that’s enough to top off for her commute which is about 4 miles round-trip and my commute is only a mile round-trip. I get to choose where my office is, and I always keep it close to my house. ? (I can literally see my house from certain angles in our tower and the view from the other side ain’t too bad either as you can see.)

I generally keep my cars between 80% and 50%. I do have to remind my wife to not let her car go down to below 20% on a fairly regular basis. But I keep a close eye on that situation, as well.

this thread has produced some great feedback and I’m really glad that I asked the question. Bear in mind though this was just a unique circumstance where I charged up the CB to way more than I needed it because I was planning on doing a towing test and then needed a way to get rid of all those extra electrons.

it just got me thinking about could this be a time saver and I think I might do it once in a blue moon if the circumstances call for it.

Much obliged!

Are you using the Tesla Mobile connector? It should provide 4 mph as you plug it in and then 5 mph a few minutes later as the car starts go to sleep. Do you have Sentry Mode turned on?

What are the current and voltage numbers that are showing. It should be 12/12 and close to 120V.

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