I’ve been at the top of Saddle Road on the Big Island with 12 mi left in the battery and 40 miles to home. I got home with 32 miles showing. That’s 40 mi travelled plus 20 mi gained. Check Polywog on the Hawaii thread. I think his current record Is approx. 50 miles travelled and over 50 mi added coming down Haleakala. You can add a lot even on a relatively short downgrade.
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Etiquette for stranded fellow Tesla
- Thread starter Shaddeau34
- Start date
When going down a mountain use what’s appropriate for the grade.
You can always have it set to Standard and just apply a little pressure on the accelerator pedal to vary the amount of regen for the situation
Too many parameters for a simple universal answer. Regen is at best ~90% efficient, so you're leaving energy on the table. But higher speeds kill range because of the squared term in aerodynamics.
And in most cases, the needs of safely traversing the roads at a pace that gets you to your destination in a comfortable time without angering your fellow drivers would prevent you from optimizing your strategy anyway.
I have a 12v to 115v ac inverter my son gave me that could be hooked to another cars 12v battery with 1000w output. I am guessing that that is about 8 amps. I wouldn’t plug it into a cigarette lighter tap because the terminal lugs on the inverter are hefty. I would use car battery jumper cables. My Volt used to charge 38 miles easily overnight at 12 amps 115v in maybe 6 hours. At 8 amps I think it would get 3 or 4 miles in an hour. So a guy with a regular car battery and jumper cables with 30 minutes to spare might have worked if the person were carrying a 1000w inverter and only had 1/4 mile or so to go. If I weren’t packed to the gills on a long trip I might carry the inverter. It might help to get me to a place to plug in to 115v outlet. I almost ran out on a trip when a road closure that I couldn’t bypass added 30 miles to my trip at night. Scary, I Barely made it to another supercharger.
I didn’t see the answer to question of where would you hook up safely on a M3 to tow someone else?
Volts x Amps = Watts
12v x ?? Amps = 1000 watts
1000/12= 83.3 amps
83 amps is more than most car alternators. Maybe in a diesel pickup, RV, etc as those tend to have bigger alternators.
I believe you’ll kill the donor car’s 12v battery pulling anything more than about 50 amps, which is only 600 watts. 600 watts @ 120v means you’re only going to get the equivalent of 5a at 120v. That’s maybe 1-2 miles per hour of charging.
You mentioned your Volt pulling 12a@120v, which is similar to a Tesla UMC on a standard 15a plug (it only pulls 12a).
120v x 12Amps = 1,440 watts.
I wouldn’t pack a 2,000 watt inverter as safety equipment. It’s just not worth the effort and extra space and weight, plus hoping someone will just park their car for 1-2 hours while you trickle charge.
Just pay for AAA or get roadside assistance through your car insurance and call for a flatbed if you’re ever stuck
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Of course you are right but I dont like the idea of my M3 going on a flatbed I have seen cars get damaged because of the entry angles. With the M3 being so low....... This was, I think an exercise in what’s possible. I thought I read somewhere that the car should not be charged with a generator. I don’t know if the Tesla would accept an inverter. Supposedly the Tesla charging system is reactive to what’s trying to charge it and the manual says if there is too much load on the house circuit it throttles back it’s load demand. I would not want to try any thing unknown for fear of damaging the cars systems. If the car already won’t drive, dont you have to go to a special setting to tow it? I am guessing that regen would not work in that towing setting.
Saghost - I agree there are many variables to consider. But wouldn't the car be able to figure it out and give you an idea of the optimum speed? At least give you something to shoot for. When it becomes self driving, maybe it will be able to make decisions based on efficiency, road and traffic conditions.
Regarding alternator size: My 1977 VW Scirocco had a 65A alternator. My 2011 F150 has (I believe) a 250A alternator. Primarily because power steering. Still an inverter on an ICE is not a great idea but OK I guess as a last resort.
Regarding alternator size: My 1977 VW Scirocco had a 65A alternator. My 2011 F150 has (I believe) a 250A alternator. Primarily because power steering. Still an inverter on an ICE is not a great idea but OK I guess as a last resort.
For those of us who experience seriously cold weather, having a "jumper cable" between two Teslas could be a lifesaver. As a driver up here in Canada, these things have happened to me on separate occasions: severe cold rapidly diminished driving distance; the route to a charger was unexpectedly closed due to a traffic accident; a promised tow truck took 2 hours to arrive. Why is this a big deal? Because when the battery goes dead, drivers may make the fatal decision to abandon their vehicles, thinking they will find heat somewhere. Yes, people have died this way (not driving a Tesla, I hope). BTW, according to one of the service people at the Toronto Tesla shop, 120V charging in cold weather can actually drain the battery, because too make energy is required to heat the cells. I know Tesla has a lot on its plate these days, but it sure would be great if they could spend some time focusing on cold weather issues, including making a jumper cable possible. Of course, the jumper cable scenario only works if another Tesla driver pulls over to help. Maybe we would also need a special beacon 
Wow. Great find.
It's massive though and no price. Wish they also had 120V AC and USB outlets so you can use it for camping and other uses besides emergency Tesla charging.
dbldwn02
Active Member
Not that this matters much but 7400ft is the gate to Pikes Peak Highway. It's another 1000+feet down Hwy24 to the valley. So, 8000 is a pretty good estimate.
dbldwn02
Active Member
Their business model looks horrible! It doesn't look like they sell it to individuals, only companies who do roadside emergency stuff. "Order a charge from Alexa while you're grocery shopping"??? And then a guy in a van shows up to plug in a portable battery to your car??? That sounds like the stupidest thing I've heard this year.
Just get a Goal Zero 3000 Lithium. Half the size and will add 6 or more miles of range before it dies.
For both BMW and Tesla "M3" there is a front tow eye you can use to tow in reverse, and you can add the rear tow hitch to tow going forward. Neither are outfitted to tow in the back without the added tow hitch but both have a screw in tow eye for the front. Most cars will be the same; sedans rarely come with a rear tow hitch stock but almost all have them available. A front tow hook adapter is on nearly every car.
Yep. But they keep winning "innovation awards"...probably from people who don't drive EVs.
That's why I follow them, to see if my initial assessment (which was "WTF?") was valid. I can see AAA buying a bunch, but what is the total addressable market there? And assuming its a quality product and lasts for 10 years or more, not too many replacement orders either. And if it isn't a quality product, not too many replacement orders either.
The device is 'stackable' so one can add more storage in cooler sized increments, at the expense of it not being "portable" anymore. It has J1772 (Level 1,2 AC) and CHAdeMO (Level 3 DC), so there's that going for it.
Great advice! Safety first, and even a quick stop to see what help is needed would be welcomed.
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