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Tesla Model 3 charging really slow at home?

davewill

Active Member
Feb 5, 2014
1,823
1,966
San Diego, CA, US
OP would get more help in the UK and Ireland subforum. I know that EU cars have three 16a modules in their chargers, allowing 3*16a=11kW charging on three phase power. That would imply that the best it could do on one phase is 16a (3.6kW), however I know that some of the older cars were able to connect two of the modules to the one phase and get 32a charging on single phase (7.4kW). I also know that some wall connectors were wired to put the single phase on multiple power pins, but this was dangerous and could damage non-Teslas and I think people stopped doing that.

I don't know for sure what the state of things are for Model 3 right now.
 
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DionG

Member
Jan 3, 2020
71
24
DFW
from what I have read in reviews, since no experience with jag ipac, i've read that you don't get anywhere near 290 that was claimed. so maybe that could be the case. ive seen numbers in the news where its more like 250. if your going based on percentages it would seem the jag is getting filled faster.
 

derotam

Member
Oct 31, 2018
825
697
Oak Hill, VA
At about 6-8 C, it’s not the battery preheating, that’s costing you. Even around freezing, and using my 120V charger, I barely lose about 10 minutes of charging time. There’s something else going on here. Just plug it in during the day and see what charge rate it’s giving you, it’s not gonna hurt your battery.

Just went out to grab something from my car. Garage is at 12C. Opening my car triggered a charging top off. Heard the coolant pumps spin up and the rear motor. Charging screen only showed 10 miles per hour of charging when it should be maxed at 23 on with 240/24A.

Opened up ScanMyTesla and confirmed battery preconditioning was active.

People underappreciate how much the car actually really wants to warm up the battery when it seemingly doesn't need to. Ohh and the target temp for the battery that the car wanted was 19C according to ScanMyTesla.
 

user212_nr

Active Member
Aug 26, 2019
1,407
741
US
"For optimum charging at home, you can install a recommended Jaguar wall box1. I-PACE is equipped with a 7kW single phase AC on-board charger2, which can fully recharge the vehicle overnight and deliver up to 35km (22 miles) of range per hour. When using a domestic socket, charging rates are slower than a wall box (up to 11km of range per hour), but are sufficient to cover the average daily commute of 60km (38 miles) if the vehicle is charged overnight."æ

"The home charging cable enables you to charge the vehicle using a domestic power socket. Ask your Jaguar Retailer for more information on using I-PACE in other countries."

Jaguar I-PACE | EV Charging Stations & Range | Jaguar

They use the word "wall box", however this term does not turn up many results in a search. It would seem that Jaguar does not have their own charger, and that they recommend others.

There is a company called "wallbox" and since the OP said single phase, 7kw, maybe they have something like this

Pulsar Plus Type 2 5m 7.4kW

I'm guessing that it is hardwired.

Additionally,

One thing that you will clearly notice about these units is that they separate the charging cord and wall-box (or socket). What this means is that the max current will possibly be limited both by the cable as well as the wall-box.

So maybe there is some need to check whether the cable that plugs into the wall-box can deliver 7kw.

Maybe the 7kw cable was sold with the Jaguar and the Tesla provided a lesser cable with similar ports (NOTE: I've got no idea about these cables).

This is different from North America where the home charging stations do not have removable cables, and in the cases where a socket is installed, we still have an electronic charging box with non-removable cable in between the socket and the car.
 
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RJUK

Member
May 31, 2019
58
8
United Kingdom
When you plug in, you should see the charging screen appear on the monitor. On the bottom line, the voltage, current and charge time is listed. What is it saying?
I need to check this the next time I charge, so will have a look and report back. I suspect this is the issue, but am baffled as to why it would be set to a lower amount than the maximum available.

Ok, so I I have a theory... You are using scheduled departure right, possibly with cabin preconditioning? If you are then the car is turning on the battery preconditioning feature to help warm the battery in an attempt to reduce any cold induced limited regen.

The noise you are hearing under the trunk is power being applied to the motor to create the heat, to warm up the coolant, to warm the battery. Battery preconditioning can use up to ~7kW split between the motors. It sounds like your car is deciding to only push power to the rear motor for preconditioning(up to ~3.5kW)

Even if you are NOT using scheduled departure, this still could be the issue.

Can you take a picture of your charging screen and post it for us to see. This can answer all kinds of questions for us very easily.
I'm not using scheduled departure, no. I just use the Tesla's "max charge" limiter to set when charging ends. (I set it to about 80%.)

At about 6-8 C, it’s not the battery preheating, that’s costing you. Even around freezing, and using my 120V charger, I barely lose about 10 minutes of charging time. There’s something else going on here. Just plug it in during the day and see what charge rate it’s giving you, it’s not gonna hurt your battery.
Thanks for confirming. Will do.

It's just your charger limitations and losses through adapters. Spouse's Model 3 charges at 48 amps with Tesla Wall Charger which is about 1.5 your rate. Did so new, does so now with ~6K on it. (48a x 240v >11 Kwh). 40% the purchase and install cost of Wall Adapter was rebated by our state (MD).
It's not my charger's limitations and no adapters are being used. The charger worked fine with the Jag and delivered power more quickly with that car. Same cable, same charger, no adapters being used, so can't be any losses from that.

I think your amperage is simply set lower than what it should be. 7kW is about 30A at 240V.

See screenshot below:
  1. Go to your charging screen by pressing the lightning icon (Red circle).
  2. Report back what the amperage setting is showing (Blue circle).
View attachment 506453
I think you're probably right. Thanks for the screenshot. That'll be useful.

OP would get more help in the UK and Ireland subforum. I know that EU cars have three 16a modules in their chargers, allowing 3*16a=11kW charging on three phase power. That would imply that the best it could do on one phase is 16a (3.6kW), however I know that some of the older cars were able to connect two of the modules to the one phase and get 32a charging on single phase (7.4kW). I also know that some wall connectors were wired to put the single phase on multiple power pins, but this was dangerous and could damage non-Teslas and I think people stopped doing that.

I don't know for sure what the state of things are for Model 3 right now.
I hope you're wrong. If the best the Model 3 can do on single phase is 3.6kW then I'm not gonna be pleased. I'll find out soon enough though...

from what I have read in reviews, since no experience with jag ipac, i've read that you don't get anywhere near 290 that was claimed. so maybe that could be the case. ive seen numbers in the news where its more like 250. if your going based on percentages it would seem the jag is getting filled faster.
That makes no sense. Regardless of how many miles I get from a charge, the Jag's battery is bigger. So if it charges at the same rate as the Tesla it should charge at less % per hour than the Tesla. What you're thinking of is measuring the charge in mph.

Just went out to grab something from my car. Garage is at 12C. Opening my car triggered a charging top off. Heard the coolant pumps spin up and the rear motor. Charging screen only showed 10 miles per hour of charging when it should be maxed at 23 on with 240/24A.

Opened up ScanMyTesla and confirmed battery preconditioning was active.

People underappreciate how much the car actually really wants to warm up the battery when it seemingly doesn't need to. Ohh and the target temp for the battery that the car wanted was 19C according to ScanMyTesla.
I would agree if I had the car charging for a short period, but it was charging for over 5 hours in the end. I'd be concerned if it took the car more than half an hour to raise the battery temp the few degrees required to get it to 19c, which would have left it with 4.5 hours or more at perfect charge temp. So it still should have charged way faster. Also, the Jag still has the same limitations and would also have had to warm its battery. I don't think battery warming is the issue in this case.

"For optimum charging at home, you can install a recommended Jaguar wall box1. I-PACE is equipped with a 7kW single phase AC on-board charger2, which can fully recharge the vehicle overnight and deliver up to 35km (22 miles) of range per hour. When using a domestic socket, charging rates are slower than a wall box (up to 11km of range per hour), but are sufficient to cover the average daily commute of 60km (38 miles) if the vehicle is charged overnight."æ

"The home charging cable enables you to charge the vehicle using a domestic power socket. Ask your Jaguar Retailer for more information on using I-PACE in other countries."

Jaguar I-PACE | EV Charging Stations & Range | Jaguar

They use the word "wall box", however this term does not turn up many results in a search. It would seem that Jaguar does not have their own charger, and that they recommend others.

There is a company called "wallbox" and since the OP said single phase, 7kw, maybe they have something like this

Pulsar Plus Type 2 5m 7.4kW

I'm guessing that it is hardwired.

Additionally,

One thing that you will clearly notice about these units is that they separate the charging cord and wall-box (or socket). What this means is that the max current will possibly be limited both by the cable as well as the wall-box.

So maybe there is some need to check whether the cable that plugs into the wall-box can deliver 7kw.

Maybe the 7kw cable was sold with the Jaguar and the Tesla provided a lesser cable with similar ports (NOTE: I've got no idea about these cables).

This is different from North America where the home charging stations do not have removable cables, and in the cases where a socket is installed, we still have an electronic charging box with non-removable cable in between the socket and the car.
This doesn't apply in my case. My charger has a tethered cable, so the same cable is being used for both cars and is rated to easily handle the 7kW of power that it can deliver. Same charger, same cable, same plug, no adapters.

I'll sit in the car the next time it charges and see if I can "crank it up" at all.

The only thing I can think is that the Tesla delivery center are cheapskates and turned the charge rate right down at delivery to ensure they didn't "give away" too much free power to customers. Perhaps it's therefore still at whatever they set it to, because I hadn't noticed. Car was handed over with only 45% battery, so could be it...
 

user212_nr

Active Member
Aug 26, 2019
1,407
741
US
OP would get more help in the UK and Ireland subforum. I know that EU cars have three 16a modules in their chargers, allowing 3*16a=11kW charging on three phase power. That would imply that the best it could do on one phase is 16a (3.6kW), however I know that some of the older cars were able to connect two of the modules to the one phase and get 32a charging on single phase (7.4kW). I also know that some wall connectors were wired to put the single phase on multiple power pins, but this was dangerous and could damage non-Teslas and I think people stopped doing that.

I don't know for sure what the state of things are for Model 3 right now.

Here's the Tesla guide for the UK (I was able to get it to load in the U.S. by adding ?redirect=no to the URL).

Home Charging Installation

It says, " Most homes in United Kingdom allow a maximum charge rate of 7.4 kW or 19 to 27 miles/hour. This is more than sufficient for overnight charging. An electrician can determine the available power at your home during a site visit and install your Wall Connector accordingly."

Since UK homes have single phase power, that would mean that the limit is 7.4kw.
 

user212_nr

Active Member
Aug 26, 2019
1,407
741
US
Home Charging Installation

Screen Shot 2020-02-02 at 6.45.44 PM.png


@davewill I think this is a definitive answer on the car's capabilities. Its from the New Zealand installation guide, but good enough.

A user also says he did 32A single phase on EU Model 3: AC charging speed?
 
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RJUK

Member
May 31, 2019
58
8
United Kingdom
OK, so I just got out of my car as I got home from work and as I was stepping out thought I could check the charge screen to see what it said. It was set to 16 amps, but wouldn't go any higher. I could set it lower, but not higher.

The car wasn't plugged in at the time though, so perhaps I need to plug the car in before it'll allow me to increase it?

At the moment I'm having issues with my charger (unrelated to this, before you say it!) but it means that I can only charge between my scheduled times whilst the company is developing the new app and firmware. As such, I can only mess around with the charge settings if I stay up into the middle of the night. I may do so tonight or tomorrow night, depending on when I next decide to charge the car.

Hopefully adjusting it upwards is possible once the car is plugged in.
 

RJUK

Member
May 31, 2019
58
8
United Kingdom
Just to keep this updated. I charged last night and checked the app as the car was charging. The app showed that the car was charging at 32 amps.

It still took from 11:47pm to 3:36am to charge from 46% to 81% which isn't all that quick. Quicker than the other night, but still not as quick as the Jaguar.

It was admittedly a bit cooler than the other night, but was still around 3 - 5C.

I'll continue to monitor things and see if I can work out why it's charging slow.
 

derotam

Member
Oct 31, 2018
825
697
Oak Hill, VA
Just to keep this updated. I charged last night and checked the app as the car was charging. The app showed that the car was charging at 32 amps.

It still took from 11:47pm to 3:36am to charge from 46% to 81% which isn't all that quick. Quicker than the other night, but still not as quick as the Jaguar.

It was admittedly a bit cooler than the other night, but was still around 3 - 5C.

I'll continue to monitor things and see if I can work out why it's charging slow.

What is the voltage showing on your charging screen? I know you are saying that it shows 32A, but what is the voltage as shown on the charging screen in the car?
 

brkaus

Well-Known Member
Jul 8, 2014
7,722
6,253
Austin, TX
OK, so I just got out of my car as I got home from work and as I was stepping out thought I could check the charge screen to see what it said. It was set to 16 amps, but wouldn't go any higher. I could set it lower, but not higher.

The car wasn't plugged in at the time though, so perhaps I need to plug the car in before it'll allow me to increase it?

At the moment I'm having issues with my charger (unrelated to this, before you say it!) but it means that I can only charge between my scheduled times whilst the company is developing the new app and firmware. As such, I can only mess around with the charge settings if I stay up into the middle of the night. I may do so tonight or tomorrow night, depending on when I next decide to charge the car.

Hopefully adjusting it upwards is possible once the car is plugged in.
For the US version, when it is unplugged it allows setting the maximum amps possible for the car (single phase). Once plugged in, it only goes down.
 

DaveRZ

Member
Nov 19, 2019
164
219
Murrieta, CA
Just to keep this updated. I charged last night and checked the app as the car was charging. The app showed that the car was charging at 32 amps.

It still took from 11:47pm to 3:36am to charge from 46% to 81% which isn't all that quick. Quicker than the other night, but still not as quick as the Jaguar.

It was admittedly a bit cooler than the other night, but was still around 3 - 5C.

I'll continue to monitor things and see if I can work out why it's charging slow.

This charging rate sounds about right to me, especially if you're out in the cold. I use about 40% of my battery daily (LR AWD) and it takes my 32 amp charger about 4.25 - 4.5 hours to replenish each night, and that's in my garage in southern California (so about 65F or 18C).

Plus, I'm using a 240 volt outlet whereas I believe UK uses 230, so at 32 amps my charging will be a little faster
 
Last edited:

derotam

Member
Oct 31, 2018
825
697
Oak Hill, VA
Just to keep this updated. I charged last night and checked the app as the car was charging. The app showed that the car was charging at 32 amps.

It still took from 11:47pm to 3:36am to charge from 46% to 81% which isn't all that quick. Quicker than the other night, but still not as quick as the Jaguar.

It was admittedly a bit cooler than the other night, but was still around 3 - 5C.

I'll continue to monitor things and see if I can work out why it's charging slow.

I will note also that these numbers support an average charge rate of ~6.87kW which matches your OP stating that you have a "7kW home charger". So according to your latest numbers, there is no problem.

46%-81% = 35%.
35% of a 75kWh pack is 26.25kWh
26.25kWh divided by 3.82 hours is 6.87kW

Looks good to me. So with that said, you have been able to get your full charging rate of ~7kW with your Model 3

Now as far as your OP goes, I still say that during that charging event, the battery was cold enough for the car to use some of the input power to warm up the battery.

All seems normal here.
 
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RJUK

Member
May 31, 2019
58
8
United Kingdom
Hmm, OK. Thanks for that.

Perhaps I'm over thinking this or something then. I was really expecting the car to charge at 10% or more per hour, based on the 9% an hour I was getting with the Jag with its bigger battery.

I think, although it's a 7kw charger it can actually put out 7.4kw or something like that.

The Tesla app said it was taking 7kw last night. The wife was pushing me to turn the light out, so I didn't have time to sit there and wait for the voltage to stabilise after it warmed the battery, so the voltage was still all over the place as I had only just started the charge.
 

derotam

Member
Oct 31, 2018
825
697
Oak Hill, VA
I was really expecting the car to charge at 10% or more per hour, based on the 9% an hour I was getting with the Jag with its bigger battery.

You can't make comparisons like that. It's simpler to just look at your charge rate. Both the Model 3 and Jag, no matter the battery size is able to accept the full ~7kW that you are trying to give it. The only thing that is going to affect how much is going to each battery is any normal power draws from the vehicle, and efficiency of the conversion from AC to DC. The conversion efficiency difference between the Tesla and Jag is not much I am sure.

You are kind of stuck because of your TOU electric rates. The only other thing you could do is get a Wall Connector on a 60A circuit and then you can get 48A or ~11kW into your car.
 

AlanSubie4Life

Efficiency Obsessed Member
Oct 22, 2018
9,425
11,327
San Diego
46%-81% = 35%.
35% of a 75kWh pack is 26.25kWh
26.25kWh divided by 3.82 hours is 6.87kW

Perhaps I'm over thinking this or something then.

Yep. The LR battery (when new) is ~78-79kWh, and the charging efficiency is about 88.4% (based on EPA results, probably using a 7.7kW UMC). This does include the final taper so the actual efficiency might be closer to 89% if you're not charging to 100%.

Between 0rmi and max rated miles (322 rated miles for you, or 299, but it doesn't matter for this), you have 95.5% of that energy available (the remaining 4.5% is in the buffer below zero).

So,

78kWh(DC)*0.955/0.89(AC->DC) = 83.7kWh AC to go from 0 to 100% (without actually going to 100% due to the taper reducing efficiency)

83.7kWh * 0.35 = 29.3kWh (46% to 81%)

29.3kWh/7.4kW = 3.96 hours (3 hours 58 minutes). (Actual result: 3 hours 49 minutes, 3.5% shorter)

Seems to be in the ballpark, given the precision on the % numbers here (up to 4% error), and possible droop resulting in slightly less than 7.4kW.

Incidentally, the charging screen will show that you've added ~27kWh (or 113 18" rated miles (or 105 20" rated miles)), while your battery energy will have actually increased by 78kWh*0.955*0.35 = ~26kWh (there is no way to see this without CAN bus access).

It doesn't look to me like the temperatures are affecting the charge rate at all. And they probably should not be at temperatures of 5C, with this relatively low SoC range (below 80%), and a low charge rate of 7kW. It just is not that much power to pump into the battery; it would get nowhere near the "regen dot limit" for that temp, even for a cold soaked pack, at these SoCs and temperatures.
 
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Rocky_H

Well-Known Member
Feb 19, 2015
6,127
7,129
Boise, ID
The app showed that the car was charging at 32 amps.
There. Just stop. You keep going from this into battery percentage hand waving between the two cars. That's all nonsense.

You are getting 32A with the Tesla. How many amps is the Jaguar drawing? If it is also drawing 32A from that same wall connector, then they are charging at the same rate. Period. They are getting the same amount of energy per second, and there is no such thing beyond that as "this one is charging quicker than that one".
 

sixela

Active Member
Apr 25, 2019
1,278
1,400
Boechout
, however I know that some of the older cars were able to connect two of the modules to the one phase and get 32a charging on single phase (7.4kW).

Same for a Model 3. It's capable of drawing 32A @240V on a single phase and to distribute it across the chargers (it could even do so with two chargers, as on the US Model 3). Even the Gen 2 UMC can do this --it's needed in the 'States, where 32A monophase charging is ubiquitous--, although you need an aftermarket adapter to a 32A CEE plug to do this.
 

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