Future charging stations are going to be easier to install - FreeWire

  • 11 December 2020
  • 7 replies

Userlevel 7
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EV charging stations from polar (now BP Pulse) is about to be easier to install without grid upgrades!


CleanTechnica: FreeWire Slides Into UK.


Worthy read!

7 replies

Userlevel 7

Tagging some peeps in case this is of interest @D10hul @Leo Moran @sylm_2000 @ArundaleP @NinjaGeek @Stephen Bell :blush:


FreeWire charger looks cooooooool

Userlevel 6

The new grid serve site is probably the best example, it’s good tech but can almost be as expensive as a 3 phase connection then there’s maintenance etc etc etc, but it will have a place even so to capture renewable and prop up the grid as well as charge EVs 

Userlevel 7
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Hmmm…. this needs further discussion here.

I’ve checked the specification for the Freewire charger. Ignore the American voltages which are at the end of the article, and let’s stick with the kW figures.

The charger outputs a maximum 120kW to one or two EVs, whilst drawing 20kW or 27kW from the Distribution Grid (depending on which paragraph you read on the spec page!).

It does this by using an internal 160kWh battery, which takes 8 hours to fully recharge from empty. So that must be approximately 45A  3-phase.

It is effectively characterised as presenting a 150kW loading to the Grid, which is the same as the Tesla 3-phase Fast chargers that have been around in the UK for a few years now. Ie that’s the grid-loading specification which permits it to be connected in the UK.

What we aren’t being told is what happens if the internal battery is already spent before you plug in. Is the 150kW loading because that’s what it takes if there’s no stored charge to supplement it?


A site about 8 miles from me installed a bank of five 150kW Tesla Fast Chargers, which was achieved by them paying the Distribution Network Operator to install an additional 1MW transformer on the 11kV line supplying the town/village.

Doing the maths suggested that they could install a 6th Tesla charger (6 x 150kW = 0.9MW). However, the surge currents take the sub-station loading too high, so it would trip out. This needs to be factored into the calculations for any charging system of course. It’s not indicative of poor design by Tesla!


Now that all seems fine until I tell you that I spent Thursday morning last week in my local substation with an engineer from my DNO. The transformer there had been installed as part of a system upgrade just 2 years ago, and is rated 500kW.

This is typical of the majority of the ground-mounted substations in this region, each of which serves around 100-200 homes through 3 or 4 separate 440v Feeds.

So to operate five of these wonderful Freewire chargers is going to require a transformer twice as large as is commonly used in my local area!


And that’s not even the most critical factor. The underground “Triplex” cables used to send the 440v feeds to our houses are rated such that they are permitted to get hot during the evening peak. The subsequent lower overnight usage allows them to cool down again before the smaller breakfast-time peak.

If/when we start putting 7kW (32A mcb) chargers on our own properties, it doesn’t take too much to realise what’s going to happen if we want to charge overnight.


So if we then add in a few nice shiny new Freewire chargers into the locality, and even if they get de-rated to 50kW each (which is an option), just how can it be claimed that they alleviate the need for costly infrastructure upgrades?

Userlevel 5

As always thanks @Transparent for reminding us of the things they don’t tell us. I was aware of the cables cooling overnight….and then my brain starts thinking about something else…..ground source heating….if when we lay new cables then run water pipes alongside the cables this could have the dual effect of helping to cool the cables whilst at the same time helping to contribute to heating our water and central heating systems. It’s all well and good installing bigger cables, bigger transformers, more battery storage and more solar panels and turbines….but we need to think outside the box...which is what Apple have done with their new M1 chip.

Traditionally computers run PCUs, GPUs, RAM, Drives and all sorts of cable between the two. The bigger the parts the more power is needed and the more heat is generated…..requiring fans to cool them and using more power. Apple have condensed all the parts onto one chip and in doing so not only made the chips faster but run on much less power, generating less heat and, in the case of the MacBook Air, eliminating the fan completely, something unheard of in computers.…

So if we have to install newer equipment and as we’re banning domestic gas boilers from 2022, surely we can kill two birds with one stone. Cool the cables and help to heat our water….all whilst protecting the environment….Just a thought.

Userlevel 7
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That’s true @Leo Moran … and I’ve already discussed with my DNO the possibility of adding GSHP coils above electricity cables whilst the trench is open.

There are two main issues:

  • Who gets to install the actual heat-pump and therefore benefit from the energy released?
  • Safety regulations require changing, which means protracted negotiations with ENA and Ofgem.


Userlevel 7

Not bad news at all:


Electric car batteries with five-minute charging times produced

Userlevel 7
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It’s really bad news if you’re seeing this from the viewpoint of a DNO.

The UK Distribution Grid is derived from a strategy which evolved mid-19th century. It simply can’t support this level of energy transfer.

The site I referred to above with five Tesla fast-chargers needed to bring in a fresh 11kV feed and install their own 1MW substation.

That’s twice the size of transformer as the one supplying my house and almost 400 others.

Just how do you think a DNO is going to deliver sufficient energy for a cluster of five StoreDot chargers? An entire 1MW substation for each one perhaps?