[Macbrief]

So I've tried numerous formulas, multiple reference websites and cannot figure out this charging speed malark.

When I charge at home on 3 pin I get 4mph max, when I charge at my works 22kw charger I get 23mph with the Polestar cable and 16mph with a third party 32a cable (both consistent through the whole cycle).

None of these numbers match up to me and I'm really confused. Every website I check tells me different numbers to this. Can someone please explain if there's something potentially not right with the work charger? Or in fact I am a total dingbat and should just stand in silence in the corner.

Thanks.

 

[polerad]

So I've tried numerous formulas, multiple reference websites and cannot figure out this charging speed malark.

When I charge at home on 3 pin I get 4mph max, when I charge at my works 22kw charger I get 23mph with the Polestar cable and 16mph with a third party 32a cable (both consistent through the whole cycle).

None of these numbers match up to me and I'm really confused. Every website I check tells me different numbers to this. Can someone please explain if there's something potentially not right with the work charger? Or in fact I am a total dingbat and should just stand in silence in the corner.

Thanks.

I’ve no idea how Polestar calculates the charging speed in mph. But it should output voltage and amps you’re getting.
What do those show in each place?

And should note the polestar max takes in 11kW for AC charging. Only with a DC fast charger (and CCS connection) would you get >11kW.

 

[Honken]

It knows the average consumption. Based on the ambient temperature and the amount of power that's going into the battery it calculate the charging speed in mph

 

[Macbrief]

It knows the average consumption. Based on the ambient temperature and the amount of power that's going into the battery it calculate the charging speed in mph

Does it though? Those numbers havent changed since day 2 of owning the car.

I’ve no idea how Polestar calculates the charging speed in mph. But it should output voltage and amps you’re getting.
What do those show in each place?

And should note the polestar max takes in 11kW for AC charging. Only with a DC fast charger (and CCS connection) would you get >11kW.

So great question because this is where I get SO puzzled. With the Polestar cable at my work charger it's 16a 230v at 22/23mph. with the 32a cable it runs 32a (can't remember voltage) but only gives me 14/15mph....

But CCS 50kw gives me 90-125mph.

 

[GDank]

It knows the average consumption. Based on the ambient temperature and the amount of power that's going into the battery it calculate the charging speed in mph

It doesn't use your consumption values ... it uses a generic default number. So if you was getting 70khw/100mi or 20kwh/100mi it would still show 20-22mph at 7kWh

When I charge at home on 3 pin I get 4mph max, when I charge at my works 22kw charger I get 23mph with the Polestar cable and 16mph with a third party 32a cable (both consistent through the whole cycle).

On ALL the following the assumption will be that the charger is delivering near to it's max output.

Using the 16A or Higher Three Phase Cable on an 11kw or 22kw : You should be getting close to 30+mph - This is because the car is maxed out at 16A on each of the 3 Phases.
Basically if it's a 3 Phase Supply and a 3 Phase Cable, then you'll get the 30+ mph.

Using a 32A Single Phase Cable on an 11kW : You will only be getting around 10+ mph ... because you are now limited to a Single 16A Phase - so half that of a 7kW charger.

Using a 32A Single Phase Cable on a 22kW : You should be getting around 20+ mph ... because now you are getting 32A on a Single Phase, the same as a 7kW


Each Single Phase can deliver 3.6kW of charging at a max 16A. You put 3 Phases in you get 3x16A (3x3.6kW). You put a Single Phase in at 16A it can only use one transformer, so 3.6kW max. If you put 32A Single Phase, it can split them to 2x16A to deliver 7.2kW. (for Americans you can get Single Phase 48A which is then split 3 ways)



I suspect the charger the 22kW charger at work has 2 Sockets on it? Therefore each socket could be limited to less than 22kWh or the Pole/Box/Unit is maxed at 22kW however has to share that between two plugged in cars. So each car gets 11kW unless one is using less power.

Was there another car plugged in?

My last guess is that because you are not getting 30+ mph when using the 3P 16A cable (11kWh) ... I would guess your work charger isn't delivering all the power it can which is throwing off your figures. So it's not delivering 32A per phase ... hence numbers are low.

 

[polerad]

So great question because this is where I get SO puzzled. With the Polestar cable at my work charger it's 16a 230v at 22/23mph. with the 32a cable it runs 32a (can't remember voltage) but only gives me 14/15mph....

But CCS 50kw gives me 90-125mph.

Seems like you're getting about the volts/amps and therefore kW you expect at each place.
The confusing thing is the mph calculation, which is likely linked to the GOM, which has been established as a tool of Satan.
I'd just ignore the mph calculation, just like I'd advise ignoring the GOM, unless you like the weather in the 7th circle of Hell.

 

[Atticman]

I've done quite a few runs with Seb's app (thanks @seb ) and the figures recorded in the app seem to correspond directly with the charger screen (both instantaneous and averaged out over the full charge) - in all the cases the mph figure was 2.5 times the kw.
Even with short charges on 50kw CSS ones, i can stare at the screen and get a pretty good idea what the kw number will be at the end

This may change when the warmer weather comes as it may just be taking the GoM number of 250 miles and dividing by 100, but it is less than a midge's baw hair away at the moment

 

[dave]

less than a midge's baw hair away

In the midlands we call it "a gnat's cock".
Let's put the global nature of this forum to real use. In your city/country, what do you call a tiny amount?
eg- that was a close race. Who won, I can't tell? There was only a gnat's cock between them.
Let's help make the world a better place.

-

 

[Macbrief]

In the midlands we call it "a gnat's cock".
Let's put the global nature of this forum to real use. In your city/country, what do you call a tiny amount?
eg- that was a close race. Who won, I can't tell? There was only a gnat's cock between them.
Let's help make the world a better place.

-

I'm with attic, regardless the creature it's a baw hair. Might just be local dialect tho.

I've done quite a few runs with Seb's app (thanks @seb ) and the figures recorded in the app seem to correspond directly with the charger screen (both instantaneous and averaged out over the full charge) - in all the cases the mph figure was 2.5 times the kw.
Even with short charges on 50kw CSS ones, i can stare at the screen and get a pretty good idea what the kw number will be at the end

This may change when the warmer weather comes as it may just be taking the GoM number of 250 miles and dividing by 100, but it is less than a midge's baw hair away at the moment

This is actually really useful info. Will keep this in mind! Thanks. By this sum means I'm getting around 9kw out of a 22kw dual point charger even when there's only one car plugged in.

 

[ProfessorCook]

A hair
A smidge
A titch

You lot have more entertaining expressions.

 

[Atticman]

I'm with attic, regardless the creature it's a baw hair. Might just be local dialect tho.



This is actually really useful info. Will keep this in mind! Thanks. By this sum means I'm getting around 9kw out of a 22kw dual point charger even when there's only one car plugged in.

must be a glesga thing (unless you are one of these east coasters)

Remember the 22kw charger is probably AC and the AC limit in the P*2 is 11kw - so getting 9kw out of 11kw (especially if the car is cold) is not too far away

 

[GDank]

By this sum means I'm getting around 9kw out of a 22kw dual point charger even when there's only one car plugged in.

Remember the 22kw charger is probably AC and the AC limit in the P*2 is 11kw - so getting 9kw out of 11kw (especially if the car is cold) is not too far away

Well the cold will be an issue if you have a high SOC, however if charging below 60% SOC I would assume you would get the full 11kW even if really cold. If above 80% and it's really cold (like -5deg C) then I could see not getting the full 11kW to be possible.

I personally think it's the charger isn't out putting enough amps if you are saying you this happens when only you are plugged in ... therefore I ask the question ... do you know the other person who is plugging in? Can you ask them what they are getting in kW or Volt+Amps, or even mph?

I do not suspect it's a problem with your car or cables.

 

[dave]

By this sum means I'm getting around 9kw out of a 22kw dual point charger even when there's only one car plugged in.

I have a single point tethered 22kw Zappi at work. The charger & app both tell me 11kw is going in until I get above 80% where it eases back to 7kw and lowe for the last bit

 

[2RatsElop]

You put 3 Phases in you get 3x16A (3x3.6kW).

This is likely not correct, technically speaking. You get square root of three times the overall power if you use three phases instead of one.

 

[krheinwald]

You get square root of three times the overall power if you use three phases instead of one.

The OBC uses all three phases to ground in parallel in a star configuration which yields 3*3.6kW.

 

[2RatsElop]

The OBC uses all three phases to ground in parallel in a star configuration which yields 3*3.6kW.

I see, thanks! My wall charger spec says that it delivers 400V * 16A * root3 (because 3-phased supply) = 11kW
That was probably the source of my confusion.

 

[krheinwald]

In the end it's the same. Theroretically, you could also build a 400V OBD which would use 16/sqrt(3)=9.2A per phase and still deliver 3*400V*9.2A=11kW. In the end, it boils down to practical reasons, as it's easier to use the 3 OBC-channels in parallel for single phase operation with higher currents.

 

[GDank]

I see, thanks! My wall charger spec says that it delivers 400V * 16A * root3 (because 3-phased supply) = 11kW
That was probably the source of my confusion.

This got me early too ... there isn't one 3 Phase transformer in the car .... there are 3 x Single Phase Transformers, one per "phase".

So each phase is transformed on a single phase bases then all 3 added back for the DC.

Where normally you just the 3 phases into one multi-transformer and get one DC supply out the other side.

When you put 32A via a 7kW home charger in the UK the car splits the 32A to between the two of the 16A transformers.

 

[pbrady999]

And the knee bone is connected to the thigh bone. You do the hokey pokey (kokey for those brits here) knee bend.

and then you charge slower than you want to....

 

[whiteco3]

@2RatsElop , @krheinwald , @GDank. You're all correct! I like the collective level of knowledge our forum exudes. I feel we could go up against the Tesla forum in a University Challenge or West Side Story/Jets and Sharks style and kick ass.

@dave I've heard of a "a gnat's cock" but never @Macbrief / @Atticman "midge's baw hair away". But you can all be correct too.