Low Battery Supercharging - 0 Kw and 90 minute charge time

[hill]

You shouldn't plan to go below 10% anyway, because too many things can happen that can cause you to use more energy than panned. That's a 20-28 mile rated range buffer, depending on your model, or the equivalent of one gallon of gas in an ICE.

iirc, the exception to the General 20 mile buffer rule would be on the newer 60D Model S's. Someone may want to chime in who has one already (our comes in a couple more weeks) you should be good to go all the way down to 10 miles. That's because they're really 75's anyways just, bigger software manufacturered buffers. I'll give it a try 1st opportunity - to see what the cutoff is.
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[Saghost]

iirc, the exception to the General 20 mile buffer rule would be on the newer 60D Model S's. Someone may want to chime in who has one already (our comes in a couple more weeks) you should be good to go all the way down to 10 miles. That's because they're really 75's anyways just, bigger software manufacturered buffers. I'll give it a try 1st opportunity - to see what the cutoff is.
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All the data I've seen to date indicates the entire locked out region is at the top of the battery - I think 0 is still 0 and shouldn't be messed with, but 100% is ~80% and fine to be at.

 

[Rocky_H]

Thinking about this a bit: This is an engineering optimization problem. Everything in/on the car is intended to be fed from the battery. If the battery has a low-initial charge, you can't draw much from it (to heat the battery), so you must build up the battery charge at a slow-rate until it has enough so you can safely draw enough to heat the battery, to charge the battery at a fast rate.
If the battery-heating circuits were designed to draw power directly from an outside source (SC or AC charger) in addition to the connection from the battery, this situation could be improved drastically.

I'm pretty sure that is exactly what it already currently (ha!) does. I think it is pulling energy from the charging source to heat the battery, but there is not very much of a charging rate shown on the car's battery display because that energy is not going into charging yet.

 

[LovelyCarrot]

i guess i shouldn't go below 10% on long trips if I don't want to spend long at a supercharger.

Hi bush - yes it was cold, about 36 F. However Tech Support said it wasn't a temperature thing, it was a charge thing. Based on some other posts I'm guessing (unverified) that you'd see the same behavior in the summertime.

 

[LovelyCarrot]

I have never heard of this and it doesn't pan out with personal experience or any of the supercharging spreadsheets that exist. Search 'tesla supercharging spreadsheet' on google and check the first couple.

I routinely arrive at 4% or less (many times with 3 miles left) a few times a month and have never seen this myself. It is true that once you plug in it will do 0Kw, few Kw, 0 Kw and then ramp up but it is typically in the 100+ kW range by the end of one minute after plugging in.

I do this in 20-95F temperatures.

Well I guess your "mileage may vary" (guess we also need a new phrase heh). It happened to me at 3% and Tesla Tech Support verified it was expected behavior. Just wanted to put it out there as a PSA for folks in case they find themselves in the same situation and are wondering (like me) whether the Supercharger was broken. BTW I did try three separate superchargers all with the same effect before calling tech support. It *might* have been a cold thing, it was only 36 degrees, but the tech guy didn't seem to think that was the issue.

 

[LovelyCarrot]

BTW folks for those that feel this is a cold weather issue, see this thread where the same issue was experienced by someone in summer
HELP: Stuck at a supercharger and the car won't charge

 

[mikes_fsd]

This thread had me do a couple tests on this. Our climate here is moderate.

On 2 different occasions I went < 5 RM (0 and 2 RM respectively) and the supercharger did not have to wait for the battery to warm up.
So, for me, it seems like this is temperature related. I will keep monitoring as we go to the mountains and other road trips.

 

[hiroshiy]

This thread had me do a couple tests on this. Our climate here is moderate.

On 2 different occasions I went < 5 RM (0 and 2 RM respectively) and the supercharger did not have to wait for the battery to warm up.
So, for me, it seems like this is temperature related. I will keep monitoring as we go to the mountains and other road trips.

Was this a newer Silicon anode battery, like 70 or 90?

 

[mikes_fsd]

Was this a newer Silicon anode battery, like 70 or 90?

This was tested with the X90D

 

[Ciaopec]

This was never a problem in moderate weather. Trip to FL and back in October posed no problems and no lengthy charge times but temperatures were never below 60. Now that the temps have dropped, a charge from 30% to 80% was slated to take 60 minutes. Initially, the charge was at 30kw and ultimately peaked at 54kw after about 20 minutes before tapering off to 35 or so. Temperature last night was 25F. The battery had been sitting in a parking garage at that temperature for about 5 hours so I'm pretty sure it was cold soaked!

 

[Moonwick]

I'm not sure if this is a difference between the 75 and 85kWh packs (I really doubt it's a difference between MS and MX) but on my last major roadtrip in my 85D I rolled into a supercharger at about -2% (yes, dipping well past "0%" ) and I didn't encounter this. The charge rate immediately lept up to 115kW. Ambient temperature was probably in the low 40s.

 

[Maaz]

This is the case with the newer batteries. old batteries would charge super fast at a low state of charge and then taper off quicker, the newer batteries charge more at a steady rate and take a little time to ramp up at a low state of charge.

 

[Rocky_H]

This is the case with the newer batteries. old batteries would charge super fast at a low state of charge and then taper off quicker, the newer batteries charge more at a steady rate and take a little time to ramp up at a low state of charge.

That does seem to be the impression I was getting from these cases. I think it might be as @hiroshiy suggested, that this may just be a phenomenon of the newer kinds of batteries that got silicon added, which probably changes their charging characteristics. I never used to hear of stuff like this longer before, with people who had the older 60 and 85s.

 

[hiroshiy]

But @mspisars mentioned she tested with X 90D which is definitely a new battery, correct??

 

[Rocky_H]

But @mspisars mentioned she tested with X 90D which is definitely a new battery, correct??

Yes, the 90 is of the new battery type, but notice that in the test example, the temperatures were moderate, so it may be temperature related.