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Small nit: I can 'jump' (read: charge the battery of) other cars with my model X, as long as the other car is an ICE car. In the frunk there is a panel that pop

Small nit: I can 'jump' (read: charge the battery of) other cars with my model X, as long as the other car is an ICE car. In the frunk there is a panel that pops off and underneath there are (unlabeled) 12V and ground terminals that I can put jumper cables on. However, I have had to get my car towed a mile to a charging station before, I really deeply wish I could have received a jump then.

omgJustTest 3y ago
Have you tried it? My Tesla doesn’t keep the terminals charged unless the car has recently been in motion and shuts down in a few minutes. Also Tesla says not to do this, jumping in the conventional sense is more as you describe, charging the other battery and may require more than 20min to do it.
- blamazon 3y ago
  Yes, I have an unfortunate habit of leaving the lights on in my ICE vehicle, and I've used it to run an inverter many times in a camping type of scenario. My memory is that there's two 12v terminals in my frunk, one that turns off and one that does not. My car is older though, pre facelift.
Retric 3y ago
That is the exact use case where solar roofs on EV’s become very useful. However you can “jump” EV’s, supply power to their 12v system and then charge off of another cars 120v plug, or a portable generator etc.
- blamazon 3y ago
  Similarly, I've always thought it's a no brainer for any ICE car to have a solar roof. At a minimum it can keep a 12v battery from dying over long parking durations or high parasitic drain, and at best it could like, keep a container refrigerated or something.
  - Mawr 3y ago
    Concrete numbers you could expect (30-40W): https://youtu.be/usqSJ7zbTLQ?t=513 https://youtu.be/usqSJ7zbTLQ?t=513
  - runnerup 3y ago
    I’d rather pay $2,000 less for my Honda HR-V than get a solar roof. But I agree it seems like a very nice option for those willing to pay more for their vehicles.
    - deleted 3y ago
      [deleted]
    - Retric 3y ago
      2k is IMO a poor price point as it’s too much for the minimal utility but not enough for meaningful power. IMO solar roofs are useful at the low end for ~400$ ICE cars could top off their battery and run a solar fan to keep the temperature down when parked in the sun. Not a huge deal, but still a nice luxury feature. Or a significantly more expensive solar roof could add meaningful highway mileage per year. You both largely offset its cost via less charging and have the option for a low speed crawl to a charging station.
      - blamazon 3y ago
        It's worth noting simple solar 'trickle chargers' can be had for less than 100 bucks, today. They are awesome for such things like additional confidence while overlanding in a remote location, or for a trailer with a winch, or an electric boat lift on a dock without shore power.
      - runnerup 3y ago
        I'd be surprised if solar panels in the roof were less than $2,000. An android-auto enabled head unit is like $500. Heated seats are often $1000 and that's "just" resistive wire. A cover for your truck bed is like $700. Premium carpet mats are $250. Unlocking your tailgate using a remote beeper instead of a physical key costs $300. > IMO solar roofs are useful at the low end for ~400$ So I agree with this, but I don't believe that would be an option, at least without some DIY aspect.
- bdcravens 3y ago
  Solar roofs provide very little power, generating less than 5 miles a day in charge.
  - Retric 3y ago
    That’s to do to the tiny amount of solar added to most cars “solar” roofs which then exclude the hood of the car etc. It’s a lot more interesting on the ~8m2 roof of a van / full sized SUV than a ~1.5m2 center roof of a car.
amluto 3y ago
I would be cautious doing that. The analogous (I think) terminals hiding under the old Model S nosecone are not particularly thick, and you might fry something. Also, if they are fused (I don’t know whether they are) and you blow the fuse, then merely opening the doors of the car if anything else goes wrong with the 12V system becomes quite complicated.
- blamazon 3y ago
  Oh yeah, I take caution, but believe me, I'm no stranger to being locked out by an inoperable 12v system. Regarding the topic of the original post, it is infuriating to try to figure out which fuses do what in this car. It is information that is simply not provided.
  - starbase 3y ago
    It is provided at service.tesla.com. Wiring diagrams, service manual, etc. Sign in with your Tesla account to get the documents that match your VIN. It's free.
    - blamazon 3y ago
      > free Not for me, after signing in and prompting for my country, takes me to a page asking for 165 dollars for a one day access, 500 for a month, or 3,000 for a year. Edit: oops, despite what I said above, after browsing around I think I found what you're talking about? Nice! TY! This is awesome! There are wiring diagrams!
jefftk 3y ago
That's not normally what people mean by "jump": jumping an ICE car is using the battery of one car to power the starter motor of another to get it running (after which it doesn't need a battery to keep running).
- blamazon 3y ago
  For me it means "no longer stranded" but I get the point. To explain the semantic ambiguity in my head, I find that ICE vehicles needing a jump often have a voltage so low (or that the battery pack or donor vehicle I'm using is anemic enough) that they need to be charged the same way, or the dead battery disconnected to allow the other battery to turn the starter motor.
- shkkmo 3y ago
  That's being unnecessarily nitpicky. Anytime someone helps you get started when your starter battery is dead is close enough that people will call it a "jump". Not having jumper cables, I've "jumped" several people by hooking them up to my battery charger and getting enough charge into their battery to start their engine.
thayne 3y ago
> I have had to get my car towed a mile to a charging station before It really seems like EVs should have easily replaceable batteries, so that in situations like that you can just have roadside service bring you a charged battery and swap it out. Or for that matter, charging stations could pre-charge batteries, and you pay to swap your drained battery for a charged one.
- blamazon 3y ago
  In that case I was towing a U-haul trailer, which leads to another thing that probably should exist: trailers with supplemental EV batteries. Not sure if the extra capacity is made up for by the extra weight though. (For context my car uses maybe ~1.5 - 4.0 times as much power when pulling the various sizes of U-haul cargo trailers)
  - WaxProlix 3y ago
    Aerodynamics are at least as bad as weight when it comes to trailers iirc. And there are at least leisure trailers that come with battery packs in them. The Lightship and Boulder come to mind for instance. I suspect it's a matter of time for more utility trailers, if it's not already a thing. Batteries are expensive though.
  - fbdab103 3y ago
    Maybe it would be distasteful, but a trailer with an ICE engine that could charge the battery while driving. Might be a trick to make it so that the generator could supply more energy than is consumed per minute.
- foolfoolz 3y ago
  it’s been done https://en.m.wikipedia.org/wiki/Better_Place_(company) https://en.m.wikipedia.org/wiki/Better_Place_(company) they were probably 25 years too early
  - blamazon 3y ago
    It's today a popular and I think ubiquitous thing in Taiwan for scooters: https://youtu.be/87T6okeKu3A https://youtu.be/87T6okeKu3A https://www.gogoro.com/ https://www.gogoro.com/
rnk 3y ago
Some AAA services carry a portable charger to recharge your ev, with the goal to give it a small charge so it can go to a nearby charging station for a full charge. https://cleantechnica.com/2022/12/05/aaa-expanding-service-now-offers-mobile-ev-charging-electrifying-aaa-member-benefits/ https://cleantechnica.com/2022/12/05/aaa-expanding-service-n.... There's nothing magic about it, you have a regular j1772 plug on the end of a generator, or a battery to provide it. Also a few evs now have 120v or 220v AC outlets, that you could put a j1772 into and give another car a charge. Sadly there appear to be no direct DC charging systems available between cars at this moment.
- blamazon 3y ago
  That map is a lot more expansive than I expected, that's awesome! AAA was the roadside assistance provider I called in that instance I mentioned and they didn't offer this service at that time. (Although the driver did an incredible job dropping my car off in a difficultly placed charging stall!)
lelanthran 3y ago
> Small nit: I can 'jump' (read: charge the battery of) other cars with my model X, as long as the other car is an ICE car. In the frunk there is a panel that pops off and underneath there are (unlabeled) 12V and ground terminals that I can put jumper cables on. "Jump" isn't the same as "charging the battery" of other cars. You can charge a 12v car battery with as little as 4A if you're willing to wait. Jump starting requires between 45 and 60A, minimum. For a larger car engine, you're looking at 80A-100A, or even more. I don't think that the EV 12v terminals are able to provide that sort of current; I think those terminals are provided so that normal camping equipment (lights, winch, things like that) can be powered.
- blamazon 3y ago
  Another commenter already pointed that out about the word jump, you can reference that comment for my reply. On the second point, I can comfortably pull 50-100 amps for an inverter from those terminals. I believe the DC-DC is 2500W on my car - I have an early model X which is over specified in many regards. It does not take long to charge an ICE battery enough to be able to turn a starter.
  - blamazon 3y ago
    And to clarify: I don't try to start the ICE with my Tesla hooked up, mostly out of superstition. I don't see why it wouldn't work given there's also a regular old 12v sealed lead acid battery behind the frunk.

omgJustTest 3y ago

Have you tried it? My Tesla doesn’t keep the terminals charged unless the car has recently been in motion and shuts down in a few minutes. Also Tesla says not to do this, jumping in the conventional sense is more as you describe, charging the other battery and may require more than 20min to do it.

blamazon 3y ago
Yes, I have an unfortunate habit of leaving the lights on in my ICE vehicle, and I've used it to run an inverter many times in a camping type of scenario. My memory is that there's two 12v terminals in my frunk, one that turns off and one that does not. My car is older though, pre facelift.

Retric 3y ago

That is the exact use case where solar roofs on EV’s become very useful. However you can “jump” EV’s, supply power to their 12v system and then charge off of another cars 120v plug, or a portable generator etc.

blamazon 3y ago
Similarly, I've always thought it's a no brainer for any ICE car to have a solar roof. At a minimum it can keep a 12v battery from dying over long parking durations or high parasitic drain, and at best it could like, keep a container refrigerated or something.
- Mawr 3y ago
  Concrete numbers you could expect (30-40W): https://youtu.be/usqSJ7zbTLQ?t=513 https://youtu.be/usqSJ7zbTLQ?t=513
- runnerup 3y ago
  I’d rather pay $2,000 less for my Honda HR-V than get a solar roof. But I agree it seems like a very nice option for those willing to pay more for their vehicles.
  - deleted 3y ago
    [deleted]
  - Retric 3y ago
    2k is IMO a poor price point as it’s too much for the minimal utility but not enough for meaningful power. IMO solar roofs are useful at the low end for ~400$ ICE cars could top off their battery and run a solar fan to keep the temperature down when parked in the sun. Not a huge deal, but still a nice luxury feature. Or a significantly more expensive solar roof could add meaningful highway mileage per year. You both largely offset its cost via less charging and have the option for a low speed crawl to a charging station.
    - blamazon 3y ago
      It's worth noting simple solar 'trickle chargers' can be had for less than 100 bucks, today. They are awesome for such things like additional confidence while overlanding in a remote location, or for a trailer with a winch, or an electric boat lift on a dock without shore power.
    - runnerup 3y ago
      I'd be surprised if solar panels in the roof were less than $2,000. An android-auto enabled head unit is like $500. Heated seats are often $1000 and that's "just" resistive wire. A cover for your truck bed is like $700. Premium carpet mats are $250. Unlocking your tailgate using a remote beeper instead of a physical key costs $300. > IMO solar roofs are useful at the low end for ~400$ So I agree with this, but I don't believe that would be an option, at least without some DIY aspect.
bdcravens 3y ago
Solar roofs provide very little power, generating less than 5 miles a day in charge.
- Retric 3y ago
  That’s to do to the tiny amount of solar added to most cars “solar” roofs which then exclude the hood of the car etc. It’s a lot more interesting on the ~8m2 roof of a van / full sized SUV than a ~1.5m2 center roof of a car.

amluto 3y ago

I would be cautious doing that. The analogous (I think) terminals hiding under the old Model S nosecone are not particularly thick, and you might fry something. Also, if they are fused (I don’t know whether they are) and you blow the fuse, then merely opening the doors of the car if anything else goes wrong with the 12V system becomes quite complicated.

blamazon 3y ago
Oh yeah, I take caution, but believe me, I'm no stranger to being locked out by an inoperable 12v system. Regarding the topic of the original post, it is infuriating to try to figure out which fuses do what in this car. It is information that is simply not provided.
- starbase 3y ago
  It is provided at service.tesla.com. Wiring diagrams, service manual, etc. Sign in with your Tesla account to get the documents that match your VIN. It's free.
  - blamazon 3y ago
    > free Not for me, after signing in and prompting for my country, takes me to a page asking for 165 dollars for a one day access, 500 for a month, or 3,000 for a year. Edit: oops, despite what I said above, after browsing around I think I found what you're talking about? Nice! TY! This is awesome! There are wiring diagrams!

jefftk 3y ago

That's not normally what people mean by "jump": jumping an ICE car is using the battery of one car to power the starter motor of another to get it running (after which it doesn't need a battery to keep running).

blamazon 3y ago
For me it means "no longer stranded" but I get the point. To explain the semantic ambiguity in my head, I find that ICE vehicles needing a jump often have a voltage so low (or that the battery pack or donor vehicle I'm using is anemic enough) that they need to be charged the same way, or the dead battery disconnected to allow the other battery to turn the starter motor.
shkkmo 3y ago
That's being unnecessarily nitpicky. Anytime someone helps you get started when your starter battery is dead is close enough that people will call it a "jump". Not having jumper cables, I've "jumped" several people by hooking them up to my battery charger and getting enough charge into their battery to start their engine.

thayne 3y ago

> I have had to get my car towed a mile to a charging station before It really seems like EVs should have easily replaceable batteries, so that in situations like that you can just have roadside service bring you a charged battery and swap it out. Or for that matter, charging stations could pre-charge batteries, and you pay to swap your drained battery for a charged one.

blamazon 3y ago
In that case I was towing a U-haul trailer, which leads to another thing that probably should exist: trailers with supplemental EV batteries. Not sure if the extra capacity is made up for by the extra weight though. (For context my car uses maybe ~1.5 - 4.0 times as much power when pulling the various sizes of U-haul cargo trailers)
- WaxProlix 3y ago
  Aerodynamics are at least as bad as weight when it comes to trailers iirc. And there are at least leisure trailers that come with battery packs in them. The Lightship and Boulder come to mind for instance. I suspect it's a matter of time for more utility trailers, if it's not already a thing. Batteries are expensive though.
- fbdab103 3y ago
  Maybe it would be distasteful, but a trailer with an ICE engine that could charge the battery while driving. Might be a trick to make it so that the generator could supply more energy than is consumed per minute.
foolfoolz 3y ago
it’s been done https://en.m.wikipedia.org/wiki/Better_Place_(company) https://en.m.wikipedia.org/wiki/Better_Place_(company) they were probably 25 years too early
- blamazon 3y ago
  It's today a popular and I think ubiquitous thing in Taiwan for scooters: https://youtu.be/87T6okeKu3A https://youtu.be/87T6okeKu3A https://www.gogoro.com/ https://www.gogoro.com/

rnk 3y ago

Some AAA services carry a portable charger to recharge your ev, with the goal to give it a small charge so it can go to a nearby charging station for a full charge. https://cleantechnica.com/2022/12/05/aaa-expanding-service-now-offers-mobile-ev-charging-electrifying-aaa-member-benefits/ https://cleantechnica.com/2022/12/05/aaa-expanding-service-n.... There's nothing magic about it, you have a regular j1772 plug on the end of a generator, or a battery to provide it. Also a few evs now have 120v or 220v AC outlets, that you could put a j1772 into and give another car a charge. Sadly there appear to be no direct DC charging systems available between cars at this moment.

blamazon 3y ago
That map is a lot more expansive than I expected, that's awesome! AAA was the roadside assistance provider I called in that instance I mentioned and they didn't offer this service at that time. (Although the driver did an incredible job dropping my car off in a difficultly placed charging stall!)

lelanthran 3y ago

> Small nit: I can 'jump' (read: charge the battery of) other cars with my model X, as long as the other car is an ICE car. In the frunk there is a panel that pops off and underneath there are (unlabeled) 12V and ground terminals that I can put jumper cables on. "Jump" isn't the same as "charging the battery" of other cars. You can charge a 12v car battery with as little as 4A if you're willing to wait. Jump starting requires between 45 and 60A, minimum. For a larger car engine, you're looking at 80A-100A, or even more. I don't think that the EV 12v terminals are able to provide that sort of current; I think those terminals are provided so that normal camping equipment (lights, winch, things like that) can be powered.

blamazon 3y ago
Another commenter already pointed that out about the word jump, you can reference that comment for my reply. On the second point, I can comfortably pull 50-100 amps for an inverter from those terminals. I believe the DC-DC is 2500W on my car - I have an early model X which is over specified in many regards. It does not take long to charge an ICE battery enough to be able to turn a starter.
- blamazon 3y ago
  And to clarify: I don't try to start the ICE with my Tesla hooked up, mostly out of superstition. I don't see why it wouldn't work given there's also a regular old 12v sealed lead acid battery behind the frunk.