Charger Issues During Extreme Cold Weather

Hi iKhalid, I have had numerous problems with cold weather charging, and have had an electrical engineer, plus several master electricians and Tesla engineers look at the situation, and finally a solution. I also park the car (90% of the time outside) - as my garage is essentially my dining room and a messy car is usually unwelcome there! There are many possible causes. First and foremost is that I find even the tiniest film of ice or condensate on the inside of the charge port or adapters can cause problems, especially after a wash in colder temperatures. Tesla, after all of their investigations, had noted that voltage fluctuations caused drops in amperage allowed, and if these continued, outright stoppage of charging. This was experienced repeatedly with both my UMC & 40amp outlet, and at a few SC CS90 outlets (outdoor). This happened more frequently in colder weather. The master electrician hired by Tesla concluded after substantial testing (they were here all day, switching on and off loads, maxxing out my system on a 200amp panel) - two findings; a) that my pole-mounted transformer was too far away from my panel (by a good 150' or so), and b) that the guage of my underground service wire was too light for the run of just over 400' from the transformer. I heard their argument, but was still skeptical. None of my computers, boiler, induction stove had a problem with these 'voltage fluctuations' - so why was the car being so fussy? The car itself was subsequently inspected on a few occasions, and no faults were found - 6 months later my precharge system went on permanent strike and bricked my battery, which has been replaced after flatbedding to MTL, but presumably this is unrelated

I asked Tesla whether a HPWC or CS90 may be installed - just as something different to try, but all parties insisted that the HPWC would make no difference and amperage would step down no matter what. Still skeptical, I purchased a HPWC and had it installed. I mounted it a good 5' away from my panel in the case that some back-induction from my boiler or panel may have been causing an issue. Now despite all gospel truths about the quality of my infrastructure, the car charges at 80amps (92km/hr) consistently, and steps down only to 69amps on the rare occasions that my 100amp boiler, stove, and charger are all in use at the same time. The nice thing about the HPWC is that it is smart enough to reset to 80amps when it can, and/or it allows the interface on the car's console to be dialed up to 80amps again, whereas with the UMC it would lock into 30amps, and cite 'bad wiring or extension cord used' warnings. Apparently I had a ground fault issue at my panel at one point also - but I really think that this all has to do with an over-sensitivity of the software to take offence when my voltage drops from 254 on plugging in, to a low of 233 in some cases. In any case, the HPWC has been a huge improvement, and one that is not really endorsed or understood by Tesla, IMHO. The speed or recharge with the HPWC has also been extremely welcome - I can plan back-to-back trips with less downtime, and precharge (battery and cabin warming for max. regen & console boot time reduction) before a trip now takes minutes where it used to take even an hour or more.

The explanation (offered to me by Tesla's electrician) for the larger fluctuations in Voltage during the colder weather, is that the overhead lines physically contract/tense up, and this causes a difference in the voltage. I scratch my head. It would therefore seem that a stretched/hot wire would be subject to a greater drop as the cross-sectional area may be reduced. Either way - it sounds like a bit of voodoo. My recommendation would be to see if you can borrow a HPWC from Tesla to see if it fixes your problem, and make sure you blow-out all moisture with a hair dryer before you take a longer trip. Does that help? A question for you - do you find your charge port door sticky in cold weather - as in needing an occasional pry open - or failure to magnetically latch sometimes?

iKhalid said:

I read somewhere that ClipperCreek is the current maker and supplier of Tesla chargers (I don't recall the source but correct me if I'm wrong, it could be ClipperCreek's video) so it could be that the operating temperature of their equipments is stated wrong.

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I think you're confusing the Roadster's HPC and the Model S HPWC. The Roadster HPC (aka "TS-90") was a rebadged Clipper Creek CS-90.

I've understood Norway has special electric system and it has maybe contributed to problems. How often this happens in Canada? If I buy Tesla, I have to charge it outdoors and weather will also sometimes be -20 C or colder here.

iKhalid said:

Just for the purpose of scraping my theory, who makes the HPWC and who makes the UMC?

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I haven't opened my UMC but I remember that one posted pictures of the internal in these forums, but in the other hand the HPWC has all TESLA internal electronic circuits, I'm pretty sure they are made in-house or designed in-house and then built elsewhere.

Hi! Sorry to see you're having issues. We've had our dual charger S85 for just about a year (dec 2013) and the car is outdoors all year. We're at 58000 km so far and have an HPWC @ 80 amps. This morning, while answering a post on Tesla Motors' forum about charging during cold snaps, I realized that our HPWC is the northernest one in Canada east of Winnipeg. Other than having the HPWC's cable change during the summer due to the known button problem (corrected since then), our HPWC is doing great outside. In my opinion dual chargers and HPWC should be standard in Canada as we have a lot of high amp outlets thanks to Sun Country's network as well as EV owners that understand the importance sharing at this stage of the game. Also the electricien that did our install mentionned that the nearest pole transformer might be a bit far so we called Hydro Québec and they did install one on the pole in front of our house. Great service by all involved : Hydro, Tesla and my electricien. We are very happy Tesla owners. Good luck. I'm certain you will find a solution.

My HPWC is outside also, and I agree, it should be standard in northern climates. The UMC was a big waste of time for me...