Customer questioning his zappi EV charger.

[Jay1989]

Hi Everyone, before I start ill admit I have very little knowledge of EV chargers etc, I have had a question from a customer who has had a 7kw zappi installed and his wife has just bought an audi a3 tfsi e. This apparently will only charge at a max rate of 2.9kw as its a hybrid, hes concerned the 7kw zappi will damage this. To my very limited EV knowledge ive said the 7kw zappi will be fine as Its the car the holds the charger and it will only charge at 2.9kw. Is this correct?

Apologies for the inane question and appreciate any response.

Regards

 

[mainline]

Hi Everyone, before I start ill admit I have very little knowledge of EV chargers etc, I have had a question from a customer who has had a 7kw zappi installed and his wife has just bought an audi a3 tfsi e. This apparently will only charge at a max rate of 2.9kw as its a hybrid, hes concerned the 7kw zappi will damage this. To my very limited EV knowledge ive said the 7kw zappi will be fine as Its the car the holds the charger and it will only charge at 2.9kw. Is this correct?

Apologies for the inane question and appreciate any response.

Regards

The battery management system protects the battery from overcharge by slowing down the charging process as the battery nears 100% and then stops charging. Making it so you can't overcharge your electric car

 

[Jay1989]

Really appreciate your reply, many thanks.

 

[Julie.]

Hi Everyone, before I start ill admit I have very little knowledge of EV chargers etc, I have had a question from a customer who has had a 7kw zappi installed and his wife has just bought an audi a3 tfsi e. This apparently will only charge at a max rate of 2.9kw as its a hybrid, hes concerned the 7kw zappi will damage this. To my very limited EV knowledge ive said the 7kw zappi will be fine as Its the car the holds the charger and it will only charge at 2.9kw. Is this correct?

Apologies for the inane question and appreciate any response.

Regards

Correct.

The charge point merely informs the vehicle of the charge point's limit (7kW), and upon request from the vehicle, turns the power on.

It is in effect a fancy socket outlet.

The charger within the vehicle then charges at whatever is the lowest limit ( in this case the charger itself).

However it should be noted that this can change; all new charge points from July 2022 must be instructable. That means if the local utility decides it, they can instruct all charge points in a region to a different limit.

So the EVCP is 7kW, but the vehicle charger is 3.6kW - will charge at 3.6kW, however the utility decides it needs to limit load so instructs the EVCP to a limit of 2kW - the vehicle will now only charge at 2kW.

With zappi you can also configure it to charge at the limit of the solar panels or whatever, so if a solar array produces 2.8kW the EVCP will limit at 2.8kW, but 5 mins later a cloud passes over so this drops to 1.5kW , so the EVCP tell the vehicle the max is now 1.5kW etc - completely dynamically as the solar production changes each hour/minute/second.

EDIT

BTW, this is where terminology is important, there is a difference between a charger and a charge point.

The first clue is in the names being different

A charger does the charging - so connects essentially directly to the battery and charges at 50kW, 75kW....150kW etc - they are big bits of kit depending on how rapid they are.

This is completely different to an EVCP which is a fancy socket outlet, and uses the vehicle's internal charger, it facilitates charging, it doesn't charge.

It may sound petty, but the misunderstandings like the one your customer has, all stem from people calling it a charger.

If its a 7kW charger - then surely it would charge at 7kW - just like my 10A car battery charger charges at 10A.

So it's a fair and obvious question if the customer thinks they have a charger fitted to their house!

 

[Jay1989]

Correct.

The charge point merely informs the vehicle of the charge point's limit (7kW), and upon request from the vehicle, turns the power on.

It is in effect a fancy socket outlet.

The charger within the vehicle then charges at whatever is the lowest limit ( in this case the charger itself).

However it should be noted that this can change; all new charge points from July 2022 must be instructable. That means if the local utility decides it, they can instruct all charge points in a region to a different limit.

So the EVCP is 7kW, but the vehicle charger is 3.6kW - will charge at 3.6kW, however the utility decides it needs to limit load so instructs the EVCP to a limit of 2kW - the vehicle will now only charge at 2kW.

With zappi you can also configure it to charge at the limit of the solar panels or whatever, so if a solar array produces 2.8kW the EVCP will limit at 2.8kW, but 5 mins later a cloud passes over so this drops to 1.5kW , so the EVCP tell the vehicle the max is now 1.5kW etc - completely dynamically as the solar production changes each hour/minute/second.

Appreciate the reply, Its one of the aspects of our job I really need to look more into and push to get better at at.

 

[littlespark]

7kW into a 2.9kW car..

Does that mean it’ll go 2.4 times faster?

No?

 

[PeakSteve]

Hi Everyone, before I start ill admit I have very little knowledge of EV chargers etc, I have had a question from a customer who has had a 7kw zappi installed and his wife has just bought an audi a3 tfsi e. This apparently will only charge at a max rate of 2.9kw as its a hybrid, hes concerned the 7kw zappi will damage this. To my very limited EV knowledge ive said the 7kw zappi will be fine as Its the car the holds the charger and it will only charge at 2.9kw. Is this correct?

Apologies for the inane question and appreciate any response.

Regards

As far as I understand, the car takes control. If it can only charge at 2.9kW, that is all it will draw. The Zappi won't care.
If you wish, you can limit the Zappi: In the Advanced menu/Supply Grid/Device Limit, set it to 13 Amps.

 

[mainline]

As far as I understand, the car takes control. If it can only charge at 2.9kW, that is all it will draw. The Zappi won't care.
If you wish, you can limit the Zappi: In the Advanced menu/Supply Grid/Device Limit, set it to 13 Amps.

The charger is built into the car, the Zappi is just a charge point.

Edit : Read Julies post above

 

[slartybartfast]

Basics of electricity here....electricity is pulled not pushed. Your phone charger is plugged into a 13A (3KW) socket, yet draws a tiny amount of power, say 5V @ 2A (10W)...

 

[littlespark]

“electricity” in the form of electrons don’t get pulled or pushed. They are just there.

Your voltage, or potential difference just sits there in a conductor until a load or resistance is applied.
That resistance is sitting doing nothing til a voltage is applied.

Those two things together give you current flow… and from there, power in kW

It is not physical matter that can be pushed into a pipe like water.

 

[slartybartfast]

“electricity” in the form of electrons don’t get pulled or pushed. They are just there.

Your voltage, or potential difference just sits there in a conductor until a load or resistance is applied.
That resistance is sitting doing nothing til a voltage is applied.

Those two things together give you current flow… and from there, power in kW

It is not physical matter that can be pushed into a pipe like water.

yeah but "pulling" and "pushing" are great ways to explain it to a lay person... We colloquially refer to an appliance drawing current (hence pulling).

 

[mainline]

yeah but "pulling" and "pushing" are great ways to explain it to a lay person... We colloquially refer to an appliance drawing current (hence pulling).

What about DC ? How would you explain that to a lay person, would you say it's constantly pushing or pulling ?

 

[mainline]

“electricity” in the form of electrons don’t get pulled or pushed. They are just there.

Your voltage, or potential difference just sits there in a conductor until a load or resistance is applied.
That resistance is sitting doing nothing til a voltage is applied.

Those two things together give you current flow… and from there, power in kW

It is not physical matter that can be pushed into a pipe like water.

They don't just sit there, they move back and forth.

 

[Lucien Nunes]

yeah but "pulling" and "pushing" are great ways to explain it to a lay person... We colloquially refer to an appliance drawing current (hence pulling).

That is the colloquial way of describing it, yes, but unfortunately it's conceptually back-to-front. The supply provides a voltage (push) and the resistance of the load allows a certain amount of current through. Until the 1950s it was quite standard to refer to voltage or potential difference as 'pressure.' I will convieniently ignore the use of the word 'tension' with the same meaning.

I don't know why 'draw' and 'pull' became standard terms but I avoid them when talking to non-technical people as I don't like to promote the wrong idea. 'Draw' is not too bad because it has the general meaning of 'obtain' e.g. to draw (withdraw) money from an account, water from a well, etc. 'Pull' is an extension of draw that strays too far away from the concept of voltage as push.
I sometimes use 'take' e.g. 'The big motor takes twice as much current as the small one.'

There's the idea of 'demand' but that is more about what the user wants from the supply, rather than the detailed process of moving charge through a potential gradient.