Here are the videos I watched. Since you are the one with the EE TECHNOLOGY degree. You can figure out if they are right or wrong. Anyway, I for one am not spending over 1000 on a battery charging at 1 to 2 miles.
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Etiquette for stranded fellow Tesla
- Thread starter Shaddeau34
- Start date
Here are the videos I watched. Since you are the one with the EE TECHNOLOGY degree. You can figure out if they are right or wrong. Anyway, I for one am not spending over 1000 on a battery charging at 1 to 2 miles.
dbldwn02
Active Member
Yea, in the first video it worked. Jumper the neutral to the ground. Not the best solution but still safe since it's your first point of disconnect. Nice! Buying it for sure now. Experticity has one for 30% off!
dbldwn02
Active Member
Oh, and I was totally making fun of my own degree, hence the emphasis on the TECH part. As any real EE would tell you, it ain't worth the paper it's printed on. Lol
> It's in there, you just cannot get access to it. (photo) [aesculus]
Not a Tesla photo (!) unless maybe a Roadster which has inverter inside the PEM box. Tesla 4 doors all have inverter attached to the opposite end of the motor from the differential.
Re charging Tesla from portable generator:
I purchased a Honda inverter genset 2.2kw and tried to charge MS and also Roadster using their respective portable charge cords. Even hooked up the 1 watt resistor but was unable to charge either Tesla. I think the Honda puts out a fairly clean waveform so ???
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Not a Tesla photo (!) unless maybe a Roadster which has inverter inside the PEM box. Tesla 4 doors all have inverter attached to the opposite end of the motor from the differential.
Re charging Tesla from portable generator:
I purchased a Honda inverter genset 2.2kw and tried to charge MS and also Roadster using their respective portable charge cords. Even hooked up the 1 watt resistor but was unable to charge either Tesla. I think the Honda puts out a fairly clean waveform so ???
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No this is not 'crazy' and there is no magic here. Think about what is actually happening during this towing test (and it was a very good test from a scientific viewpoint): The Tesla was towed at 18 mph but the Hybrid was expending much more energy than that which would be needed to propel that same Tesla at that same speed. The Hybrid was really working, unfortunately we cannot see how tight the tow strap was during that pull. Also of course the Hybrid is a powerful car; it could have easily towed the Tesla even faster. So during the pull much more energy was going into the battery than was being expended just to move the Tesla itself, by a factor of from 4 to possibly 10 depending on how you might accurately make such an estimate. In the MS you have two regen settings which will make the pulling harder or easier for whatever speed you choose to tow the car. And 15 to 18 mph is generally a safe speed to choose. But if you select TOW MODE you will get NO regen charging at all, just a much easier pull. So if you are rescuing a Tesla that could not quite make it to a supercharger the prudent choice would be to use TOW MODE since 'why haul coal to Newcastle'.
This test was the same as if you descended a steep mountain grade for the same distance, one mile. Try it with your Tesla. My favorite was a 26 mile downgrade in the Rockies where I ended up with the same (or more) battery capacity.
> Jumper the neutral to the ground. [dbldwn02]
Unfortunately we don't see into this outlet box so we don't know if a resistor was used or??
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Top of Mt Washington:
Bottom of the Mountain:
Notice, 8 miles added to the trips. 22 miles *added* to the range.
Keep in mind, the car adds range in three or four mile blocks, not by the single mile like it goes down.
haha, it barely worked. He got 2 miles total from the battery! It's 50lb and takes all night to charge. Plus $1800, that's like 10 tow truck cost. (btw, i pay $5 a year for road side assistant from my ins that comes with towing). To me it's just not worth it. The second video had better result, but too much trouble and at the end, they still don't recommend it.
gigawatt1010
Member
With the number of superchargers available, plus the number of destination chargers, plus the number of other non-Tesla EV chargers, plus the big screen that tells you how much you have left (not to mention the Navigation that calculates your SOC and if charging is needed or not for your trip) - there's almost no excuse to run out of charge. With the exception of an inherent failure of the batteries, running out of charge is practically self-inflicted.
Yeah I think this thread has disclosed that the best thing to do is not to drive till you run out of charge.
Stop before you run out and are stranded on the side of the road.
If that does happen, call a tow truck and get dropped at the nearest Supercharger.
Stop before you run out and are stranded on the side of the road.
If that does happen, call a tow truck and get dropped at the nearest Supercharger.
Just like charging to 100%, battery degradation accelerates if you go much below 10%.
With three hundred plus miles of range to work with, why take chances and push the limits?
7.6 miles in 25 minutes on the image makes the average 18.2 mph, which fits my subjective 15-20.
Didn't know if the pictures were taken at the actual beginning and end of the run, but thanks for the info. I see you averaged -1078 wh/mile. With your average speed of 18.2 mph, that's a regen of 19.6 kw. So this is a lot less than the 60 kw you might generate if you towed the car at a higher speed and didn't control regen with the accelerator.
Would you say this is a steep grade?
4,723 feet gained in 7.6 miles, meaning an average of about a 12% grade, and it was actually more consistent than I expected.
Not the steepest I've ever climbed, but certainly close, and I don't think I've done anything steeper for anywhere close to as long.
dbldwn02
Active Member
I do Pikes Peak and Mt. Evans a couple times a year. 8000 foot elevation gain. I gen about 10-20 miles on the way down plus my brakes are ice cold when the ranger checks them at the mid-point. Always so proud when that happens! Heat is not an issue at all for the battery, even on warmer days.
Definitely not what I'm buying it for. Just a nice plus that it works.
The one I'm buying is 3 times bigger (weight: 68lbs) than the one in the video, so I can hook it up to my house in case of a power outage. Charge with 3-4 panels during the day. (Only during power outages) Use it at night for lights and refrigerator...oh, and WiFi! Can't live without that of course. And it's great for off-grid camping! Heated blanket at night is niiiiice.
$2100 for a 3kWh portable battery isn't a bad deal.
Pikes Peak is 6715 feet (7400 to 14115) over 19 miles of road, so not nearly as steep.
I'm really struggling with Mount Evans. Lots of sites claim either 7000 feet or "over 7000 feet" of gain, but none give an exact number that I can find.
The road appears to start in either Idaho Springs (7526 elevation) or Bergan Park (7798 elevation), and go to 14260. Neither option gives even 7000 feet, let alone 8. And over 28 miles, so not as steep as Pikes Peak.
With the Raven's higher regen, I only touched the brakes once coming down Mt Washington - and that was only because the idiot in the Kia in front of me decided to jam himself right into the narrow spot before yielding to climbing traffic.
This won’t work in the described situation. Once your Tesla shuts down at zero miles of range, there’s no regen available. So if in the OP scenario you do try to tow a low/zero SOC Tesla there won’t be any regen. Towing with a tow strap just to relocate the car may work, but only so long as the 12v battery holds on to provide electrical power steering. Braking may be severely compromised though causing the low-SOC Tesla to rear-end the tow vehicle.
In the end your best options are a 240v generator and UMC or just wait for a flatbed tow truck to take you to a Charger.
Just the general idea you can tow the car to charge it. Yes, that’s technically possible if the car is already above a minimum SOC and regeneration functions, but I can’t see a use case for it unless you’re in the Australian outback trying to go 500 miles between charges and have a buddy with lots of gas to pull you. If you’re planning to use towing to charge then you should just trailer the car or bring along a 240v generator.
I just cannot see any situation where charging by towing is feasible and safe.
OK. But I wasn't advocating charging by towing. I was disputing how many miles they claimed they added by towing in the video.
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