# [Tagging] charging station power output

Warin 61sundowner at gmail.com
Sat Mar 11 00:17:18 UTC 2017

```On 11-Mar-17 05:23 AM, lucas-osm at use.startmail.com wrote:

> Calculating the max. power is really easy. You just need to know the max. amperage (I), the max. voltage (U) and the number of phases (#np) the current is delivered in (do you say that?).
> p = square_root(#np) * I * U

Measuring AC has a few methods; peak, apparent, ...
but most people are interested in the root mean squared (RMS) values - these are equivalent to the DC effects.
Where the AC values contain no information on what measurement method is used it is usual to assume that rms has been used.

> So a normal Schuko socket would give us roughly square_root(1) * 16A * 230V = 3,7kW at best.

For RMS calculation; 16 V (rms) * 230 V (rms) = 3.68 kW (rms). [no square root required]

I'll ignore the rest until this

> What about adopting this scheme like charging_station:output=* to specify the max. power output of the whole station, distributed over all available sockets. And socket:[socket_type]:output=* to specify the max. power output of one specific socket.
>
> An example:
>
> charging_station:output=98kW
> socket:type2:output=43kW
> socket:type2_combo:output=50kW
>
> As far as I know, these values are always provided on the station itself. On the front to inform the user of it’s max. power per socket and on the back there’s a specification of the input of the whole station / max. output of all sockets.

Socket power:

Most sockets have a stated maximum for any installation no matter where they are installed (house, factory, charging station).

I think this will be the same for your charging stations? In other words - this does not change in a given distribution area (country).

From this you can determine the minimum recharge time - assuming the maximum socket power is available, an optimistic value.

Charging Station Power:

Where a charging station limits the total output power due to the number of sockets in use ...

You cannot determine from OSM how many are in use at the moment, nor
how many might be in use in an hours time nor their respective loads (and these may well change over time)

... so you cannot determine the charge time ... because of the variable number of sockets and their power requirements that are in use now and into the future.

So the information maybe of little very real value?

It might be used to determine the maximum charge time ...
assuming you get the minimum power possible from the charge station, this would be a very pessimistic value.

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I agree with using *:output=* for tagging .. but see little real world application?

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