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Slow Charging Rates and Times

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We picked up our 2016 Model S 90D on March 31, 2016. In April we took a trip from Pittsburgh, PA to Atlanta, Ga and back using the Tesla superchargers. The trip and car were great. Around late summer we started to notice charging was taking longer and the the charging rate was significantly less than we had been experiencing. This got worse as the weather got colder. We got lots of "advice" on cold weather charging but having a degrees in Physics and Engineering I had serious doubts about the "advice" so I started logging remaining range mileage at the start of charging, start time and date, voltage, amps (old display data) temperature, charging station, # cars charging etc. Nothing seemed to supported the "advice" I was getting about charging strategies. After several emails and phone calls with Tesla support over the winter (Nov 2016 - Feb 2017) Tesla engineering finally said I had a bad battery coolant pump. After the replacement pump was installed the charging rate and times improved somewhat but were still significantly less than our initial experience. So I continued with my data collection and discussions until Tesla engineering finally figured out I had a bad fuse block. After the fuse block was replaced the charge rates and times improved dramatically!!! So here is my advice if you are experiencing reduced charging rates and longer charging times. Start a log like I did and bug the hell out of Tesla support until their engineers actually look at your car's data. My guess is you have one or more of the issues I had and it seems you do need to be a rocket scientist or at least an engineer to get Tesla to really look at the issue and not just feed you the company standard line.
 
It is difficult to compare because when we got the car (March 2016) the charging displays provided voltage and amps. Then the car display and eventually the APP display were changed to mi/hr and kW (worthless information to an engineer!)

Before the battery coolant pump was replaced we were seeing charging rates
started with 138 mi range initial charging 38 mi/hr / 11 kW (50 min estimated time to 90%)
started with 76 mi range initial charging 30 mi/hr / 8 kW (50 min estimated time to 90%) one hour later 36 mi/hr / 14 kW at 111 mi range (gain of 35 mi) still 50 min estimated time to charge

After battery coolant pump was replaced we were seeing initial charging rates in the 75-85 mi/hr and 50-70 kW. We also noted an improvement in how long it too for the energy restrictive bars to disapear.

After the fuse block was replaces we see 200+mi/hr / 100+ kW charge rates. We recently (35 F day) did a 200 mile charge (52 mi initial to 254 mi) in one hour!! just as we experienced when we first got the car. Also the energy restrictive bars disappeared during the charging (the battery actually warmed up as it was supposed to). Too bad it took me over 6 months to convince Tesla there was something wrong with the battery/charging system.
 
It is difficult to compare because when we got the car (March 2016) the charging displays provided voltage and amps. Then the car display and eventually the APP display were changed to mi/hr and kW (worthless information to an engineer!.
As an engineer, couldn't you just multiply your volts and amps data to compare it to the kW data you now see?
 
Thanks for the info! I was thinking about the battery temperature, but I monitor it closely and I don't see any difference from a few months ago when I got normal charge rates, compared to now when I get slower charge rates. The reports of getting slow charge rates are also so many that I doubt all those people have bad pumps or fuse blocks.
BTW, Teslafi.com logs every possible data in one minute intervals. No guessing, no writing down numbers. And it's easily exported into a spread sheet.