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Charging issue

Charging issue

Sorry, just taken delivery of my Model 3, and so new to the forum, and I'm not sure how to search the forum to see if my problem is answered in previous posts.
I'm home charging and manage a rate of 25-20 ml/hr. After about 2 hours this drops to 6 ml/hr. The only way I can get back to the higher rate is to unplug from car and charger unit, then plug back in. I've tried stopping and re-starting charging without unplugging, but that doesn't work. Can anyone advise?
Thanks

derotam | September 20, 2019

Is there any error that shows on the screen in the car? When it goes down do you get any kind of notification from the Tesla app on your phone?

Are there any red lights on the mobile connector when the charge rate goes down?

It could be just about anything at this point without more info.

donharvey2323 | September 20, 2019

Are you using the charger that came with the car or something else?

d.sharma | September 20, 2019

No warnings nor notifications, no red lights. After it happened the first time, I've kept an eye on the app. Three time I've charged and it's happened each time. I'm using the cable supplied by Tesla and the charge point (eon) was installed by a Tesla recommended electrician, Thanks

TeslaTap.com | September 20, 2019

The drop off may be normal. As the car gets near 100% the charging rate drops. These charts show the taper for connected to a Supercharger, but the same thing happens with a home charger, but it's flat for the lower 90% or so: https://teslatap.com/articles/supercharger-superguide/#tapered

Tronguy | September 20, 2019

@d.sharma: Sorry to rag on you like this, but: You've got a new car. Read The Manual. I can kind of tell that you haven't, quite.
Look: A Tesla has a maximum charge rate. With a Supercharger, with the car at 20% or so of charge, at 150 kW one can get around 600 Miles of Charge per Hour (Call this MoCpH). That works until one is up around 50% of full charge at which point the car slows down the charge rate to keep the battery from overheating and becoming damaged. By the time it's at 80% the rate of charge is a lot less, I think around 80 MoCpH. (I forget, others will correct me, I'm sure.)
So: I charge at 250V@48A which results in a rate of 45 MoCpH. I'm pretty sure the car gets to the 90% of full charge that I routinely charge to at that 45 MoCpH rate. Going higher than that.. the max rate slows 'way down as one approaches 100% of full charge.
So, you're seeing a significant slow-down. I therefore deduce that you're charging to 100%. And this is why I know you haven't read the manual: The Manual, information on-line, and any number of the people here in the forum will tell you that routinely charging to 100% is a bad idea:
1. It wears out the battery.
2. You don't get any regen braking until the state of charge has dropped some percent.
3. The Manual says to go to 100% _only_ if one is about to go on a long trip.

I charge to 90%; Elon has said that's OK, but there's any number of the maddened crowd around here who will rush in and state that 80% or even 70% is better, for various arguments about battery longevity.

Finally: Was this really a Tesla-certified electrician? While there are people with Chargepoint wall connectors (they're not chargers: The charger is in the car, the box on the wall simply supplies 250 VAC and tells the car how much current it can supply, maximum. The car decides how much current to draw.), they're not wildly popular around here, mainly because a Tesla Wall Connector costs $500 and can do up to 100A with the right breakers. (Mind you, like I said, it's the car that decides what current to draw: SR cars do up to 32A max; LR and up can do up to 48A; and there's variants of the Model S that can do 100A). But the Chargepoints are either (a) less current or (b) more expensive than the TWC for the same current. So: sure about that electrician?

d.sharma | September 21, 2019

I read the manual more than any other - knowing that owning an electric car is very different. From the very first charge I set to 80%, largely for the regen braking. If this was simply a tail off as the battery reaches full charge, why would it happen at 50% charge, and be resolved by unplugging & re-plugging.

kevin_rf | September 21, 2019

Trying to diagnose over the internet without the full details is difficult, if not impossible.

Remember the car monitors the input voltage and will adjust the rate accordingly if there is an issue with your setup.

For instance if you are using the NEMA 14-50 adapter that come with the mobil kit, this may indicate something is not kosher with the outlet you are plugging into and it is getting very hot due to a loose connection. Or you have a ground issue. Actually dropping to 6mph sounds like one of the 2 phase 240v legs is dropping out.

I would get the wiring inspected.

Information that would be helpful:
What are you charging with, mobile kit, wall connector/charger and brand?
Outlet type?
Size of the breaker in the breaker box?
Are you using an extension cord?
What is the voltage and current you are seeing in the car when you start charging?
What is the voltage and current you see when the event occurs?
What is the light pattern on the charger port, the mobile connector?
Is anything getting hot or smoking?

Four instance the NEMA 14-50 should be reading about 240v 32amps 30ish mph while charging. 24-25mph indicates low voltage or current limiting right out of the gate. When at 6mph if a phase dropped out, it might read something like 120v 20ish amps. Will the car even allow that, it just error out?

Get that wiring inspected.

peter.watson51 | September 21, 2019

I wonder if it could be that electrical circuit. Is the receptacle NEMA 14-50? When you first plug the car in, take note of the Voltage as well as the current??

d.sharma | September 21, 2019

Thanks Kevin, that's helpful. I was trying to figure out where to start: connector, lead or car - sound like I need to look at the electrics first. I did contact the installer on Thursday and I'm waiting for them to get back to me. It has reached up to 30 mph when first plugged in: 240v & 32A, current drops off when the rate slows, but I think the voltage stays the same. Nothing feels hot when I unplug. It sounds about right that pehaps the car is protectively dropping the current because of a build up of something that is released when the lead's unplugged. I presume the installer would have checked the house's wiring was OK for the wall connector - but shouldn't presume anything!
I'm not using an extensionI'll look to get more detail next time: light patterns etc. It's an EO Mini Pro connector using a Type 2 connector.
I'll see if I can access a public charger to see if this is associated with any problems to try and isolate the issue to the home unit.
Thanks again

rob | September 21, 2019

It could be as simple as the air conditioner coming on. When I charge my car at work I get about 22 mph. But if it gets hot, the AC will come on and the charge rate will drop to about 5-6mph.

kevin_rf | September 21, 2019

Based on what I can find on the eo mini pro, I assume you are in the UK.

There are some significant differences between the US and UK charging setup. Specifically, it sounds like the Type 2 is an UK Ev specific equivalent of what we in the US use the NEMA 14-50 for.

So one would assume you are going from the car to the eo mini pro with the Tesla type 2 cable. So, no adapters in between.

I like the idea of trying a different charging location, and seeing if it repeats.

d.sharma | September 21, 2019

Thanks Rob, charging in the evening, so it's cool - no overheating problems in Scotland! Thanks again Kevin. If I get to the bottom of things I'll post again for others. Can I ask how you find posts - there doesn't appear to a search function on the forum?

d.sharma | January 12, 2020

Finally worked out how to find this post to update it. The issue was that the charger was sensing the car was in a deep sleep after two hours and seemed to reduce the chaging rate (eo mini pro charger, using the JuiceNet app). The solution was to let the app think the car was a Tesla Model S!

rehutton777 | January 13, 2020

Wow - - that sounds weird to me. Has anyone out there heard of a car eventually (after a period of time) reducing the charging speed because of "the charger sensing the car was in a deep sleep"? My Model 3 has NEVER displayed that sort of activity. It sounds strange because the car "knows" it is being charged and is presumably awake during the process (it continuously reports out the charging status) - - why would it slow the charging rate down?

rehutton777 | January 13, 2020

I agree that, using a level 2 charger, the charging rate will slow down as the battery is close to capacity, but I charge routinely to about 90% using the level 2 charger (240 V at 32 A), and my charging rate NEVER slows down from 32 miles/hr prior to shut-off. The characteristic stated by OP just strikes me as very strange.

volfanwes | January 14, 2020

when installing the wall charger at home, can this be accomplished by using a 240v plug or must it be hard wired? I have sent emails and messages to Tesla on this with no response. Any perspective or insight is appreciated.

stingray.don | January 14, 2020

volfanwes,

You can have a nema 14-50 Installed and, with the adapter, you can use the provided mobile connector.

CharleyBC | January 14, 2020

"when installing the wall charger at home, can this be accomplished by using a 240v plug or must it be hard wired?"

The Tesla Wall Connector (https://shop.tesla.com/product/silver-wall-connector) is hard-wired, if that's how you choose to go. That allows you to put it on a 60A circuit, charging the car at 48A (assuming you have a LR battery).

Otherwise, see what stingray.don said just above. That's what I use at home.

Passion2Fly | January 14, 2020

@volfanwes
Yes, it can absolutely be done. Go to Home Depot and buy a 14-50 dryer power cord. Use it to connect your wall charger to the 14-50 outlet. It must be installed correctly. Also, make sure that you program the wall charger to 40 Amps max.

Coleman Cable 90468808 50-Amp 4-Wire Range Power Cord, 6-Foot, 6', Black https://www.amazon.com/dp/B0002YURAW/ref=cm_sw_r_cp_api_i_C7MhEbKFCMKFP

Passion2Fly | January 14, 2020

@d.sharma
“ The solution was to let the app think the car was a Tesla Model S!” Are you trolling or are you for real??

iammikeb | January 14, 2020

I bought my Tesla just over a month ago and recently noticed that the Wi-Fi stopped working. I assume it was a promo and I need to now pay for it. What do I need to do?

iammikeb | January 14, 2020

Does the Tesla have AM radio?

Earl and Nagin ... | January 14, 2020

@mikeb,
WiFi should always work. If you're sure it isn't get it to a Service Center.
There's no AM radio on the Model 3. Some (like me) wish there was, others gloat because they think they're too cool for AM. I know I'm not cool and I know what AM is good for.

rehutton777 | January 14, 2020

Iammikeb: Why are you asking wi-fi and radio questions on a thread discussing "charging issues"? Start another thread. And NO, Tesla does not have AM radio!

Big_Ed | January 14, 2020

"I know what AM is good for."

Receiving secret messages in morse code from the KGB?

jallred | January 15, 2020

The juice net app has a way to set current and maximum charge level. This isn’t necessary. For model 3. But it could be useful for other cars. Our leaf charges until full. My wife uses the juice net app to limit the leaf charging to 80/90 %. If I plug the 3 in and don’t change the car in the app, the charger stops when it thinks the leaf would be at 80%. Tesla app says charging interrupted.

This could be your issue.

volfanwes | January 15, 2020

thanks all

Scrannel | January 15, 2020

AM radio is incredibly useful, if annoying. During the Wolsey fire everything was down -- power, cell service etc., for over a week. To get any idea of where the fires were, AM Radio was the best.