EasyEVSE Build (part 2)

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Building and testing the 1kHz square wave oscillator and thinking about EVSE states of operation. Big thanks to Bernhard Walter for letting me share his AnalogEVSE project.
AnalogEVSE webpage and schematic:
www.analogevse.xyz/AnalogEVSE-...
www.analogevse.xyz/analogevse-...
Other datasheets:
en.wikipedia.org/wiki/SAE_J1772
omronfs.omron.com/en_US/ecb/p...
www.hlktech.com/en/Goods-14.html
www.ti.com/lit/ds/symlink/lm3...
e2e.ti.com/blogs_/archives/b/...
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Interested in my new garden workshop? Follow the entire build on Julian's Shednanigans:
/ @juliansshednanigans
Join me on Odysee/LBRY: lbry.tv/$/invite/@julian256:d
Octopus Energy referral link: share.octopus.energy/aqua-birch-918
(We each get £50)
#EasyEVSE
#ElectronicsCreators

[@romancharak3675]

Thank you for taking us along for this fascinating journey, Julian.

[@JulianIlett]

You're welcome :)

[@steveroberts1861]

Great to see you back doing this sort of progressive design / constrution video.

[@fredflintstone1]

Nice video things moving forward slowly and with you explaining every step is good🙂

[@andymouse]

Squeak!!!!!

[@JulianIlett]

It'll speed up in the next video (because I've just finished wiring it all up).

[@fredflintstone1]

@@JulianIlett Spoiler alert then🙂

[@JulianIlett]

Spoiler: It's looking good :)

[@fredflintstone1]

@@andymouse cauliflower Cheese!!!!

[@ncot_tech]

I now want to probe my PodPoint EVSE when the car is plugged in and not charging, just to see what's going on. My car has a delayed charge setting and some interesting relay clacking happens in both the car and EVSE when I activate that. There's also a setting in my PodPoint to activate charging at specific times if your car can't do that itself. I know the PodPoint has all the ground fault detection stuff in it, so it wouldn't surprise me by also detecting if its relays are stuck - possibly by bridging live/neutral with another relay/power transistor thing to trip the 30A breaker. Can't wait until you progress to building your own CCS charger from a bank of Lithium Iron batteries 😉

[@JulianIlett]

Bridging across live and neutral doesn't sound like a very good idea :/ CCS rapid charge is a very different animal. I won't be playing with the 400V battery :)

[@AJB2K3]

Even after watching you solder the electrolytic I still thought the 2caps and psu module was a duel connector!

[@followthetrawler]

I know literally nothing about EV charging and so am really liking this series. Isn't there a case where, for example you have a domestic power outage, the CP signal goes to 9V, your 'connected but no power' AB state indicates the vehicle cant draw power, but couldn't it 'supply' power if it supports vehicle to load? You wouldnt want the vehicle feeding back to the domestic supply. I know thats all rubbish, just letting my fingers do my thinking....

[@JulianIlett]

V2L (vehicle to load) and V2G (vehicle to grid) are very different. V2L requires just a simple inverter in the car that generates 240V AC from the car's battery. V2G requires an inverter that can match your house mains voltage, frequency and phase as well as having anti-islanding and other safety features. The latter is similar to a solar inverter.

[@edwardvanhazendonk]

Hi Julian, thanks for explaining the circuit and what it does. Isn't stage AB to let the car know it's connected but the mains is on standby? That way the car might not go into error because it cannot charge. (Also depending on how the car has implemented all circuitry and standards)

[@thomasvnl]

I think that's pretty much what Julian explained because he also explained why state A is actually a "non-state" or at most a prelude for that AB stage. As long as the EVSE supplies 12VDC, the resistance of the EV car makes it 9VDC. So State A only exists if the car is not connected but the outcome state, state AB, is the state that is interesting for that standby state you mention. I still think its interesting that electric cars use such an analogue way of communicating with any charger, but it seems pretty universal this way which is great, without serial protocols that can fail you (by losing bits). My only concern is the DC voltage applied at the pilot connectors as that leads to corrosion on the connector while no EV is connected, due to polarity and moisture in the air. But maybe I am exagerating because all these EVSE chargers almost always have some kind of flap/some cover over the connector. But I know of one person that lives in my neigbourhood who has a fixed cable (with the connectors exposed to the elements) so he might suffer from oxidation on the pilot connectors over time because of this DC state.

[@Pi-Tutorials]

State AB, could be where vehicle is plugged in, but the EVSE has a physical lock, such as home Pod Points to disable charging. It may also be used when a public charger is negotiating payment. What state is in place when the vehicle is in timer mode, does the vehicle disable the resistor so that charge does not commence? Is this then in state A?

[@TheEmbeddedHobbyist]

Not sure i like the mains relays being enabled and the circuit haing to provide a signal to turn them off. I think i would perfer the circuit to power up with relays in the off state and then driven on when a car is detected. not too bad as there is no uP controller which could fail and leave the outputs always enabled, i quite like a capacitor connected drive signal, so if the enable stops switching the output goes in to the safe state. a stable high or low with not hold it on. Still good to see the thinking behind design.

[@JulianIlett]

Well, it's all a matter of perspective. Now that the comparators are in circuit, the relays are held off most of the time. The relays turn on when a suitable resistor is put across CP and PE. I used a capacitor connected drive on a LED matrix project years ago. There were 7 rows of multiplexed LEDs being overdriven by a factor of 7x (about 100mA per LED). The capacitor connected row selector prevented the LEDs burning out if the multiplexer software had a bug.

[@TheEmbeddedHobbyist]

@@JulianIlett I think with a total hard wired logic is not much of an issue, but put some firmware in there and i would look for a form of fail safe.

[@neondawnfpsgaming]

can you do it Electronics start up kit video? like parts and equipment. if you do, please include search terms so we can buy the kit you make.

[@FireballXL55]

Hi Julian Could it not be that the car interface is powered from the 12/9V and has a diode and a capacitor off the 12V/9V square wave line to smooth its supply?

[@JulianIlett]

That wouldn't be possible as the 12V/9V is connected to the car through a 1k resistor, so it would only be capable of supplying a few milliamps (microamps if you didn't want to upset the voltage level signalling). Having said that, PP (the proximity pilot) is fed from the car through a 300ohm resistor - so that could possibly be used as a power source.

[@mrlithium69]

@17:35 you can see some of the empty solder holes flashing in strange patterns. What caused this ? Camera interference ? Trees blowing in the wind outside affecting the lighting?

[@wthornton7346]

That is weird isn't it. Maybe, as you suggest, it is a camera lens abberation?

[@JulianIlett]

There's a solar powered wind turbine (a toy one) on my windowsill which can cause flashing light effects on the desk.

[@David_11111]

yay

[@bobnorman1000]

Julian can you add a link to the oscilloscope your using please

[@JulianIlett]

All I can tell you is it's an Aarontek DSO Nano Pro. It may have come from Banggood, but I honestly can't remember.

[@andymouse]

Will EV's ever have a flap on the side with a self retracting cable and standard UK plug on the end so you just pull it out and plug it in the wall and thats it ?...cheers.

[@JulianIlett]

Yes, the Renault Twizzy and the Citroen Ami both have that :)

[@fredflintstone1]

Grated Cheese!!!!!!!

[@JulianIlett]

More like Pizza with multiple toppings!!!!!!!!

[@andymouse]

@@fredflintstone1 Squeak !!!!

[@nl1cat]

Pull down ? It's negative voltage so shouldn't it pull up ?

[@taranagnew436]

what's the osiloscope you have?

[@JulianIlett]

It's an Aarontek DSO Nano Pro. It may have come from Banggood, but I can't remember.

[@CollinBaillie]

Watching on an iPhone 8+. Pretty sure the oscilloscope showed Vpp 12.5v. Yet your "state" graph shows Vmax of 12v and Vmin of -12v. That's Vpp 24v. Do you need to match this?

[@JulianIlett]

Yes, the CD4060 is connected across +12V and 0V, so the square wave is 12V only. Now I need to add the comparators and the transistor driver to get a 10% 1kHz 24V waveform

[@ahmeddawood8847]

hmmmm

[@markhodgson2348]

Why are you bothering with this project

[@JulianIlett]

Why not?

[@BenjaminGoose]

What a weird question.

[@piconano]

This project is no good! No blinking LEDs anywhere!

[@JulianIlett]

Easily added :) In fact, I may add a couple of LEDs across the relay contacts to indicate when the relays are pulled in.

[@piconano]

@@JulianIlett I think you need an Arduino with a blink sketch to make it pop :)

[@michaeltempsch5282]

@@piconano This clearly needs a "supercomputer" LED board for proper blinkenlichten...

[@piconano]

@@michaeltempsch5282 even a better idea. He has one in the shed.