Minimalist Electric Car Charger

[@pintokitkat]

You could always ask Electroboom to test your power bank mains theory!

[@JulianIlett]

I'm tempted to try it myself :/

[@mikeselectricstuff]

I suspect some cars may throw an error if it sees voltage there when it shouldn't be due to lack of relays. Some cars also do an earth loop impedance check, so if N is not tied to PE then they won't charge. The response time to PWM is defined in the IEC62763 standard as 5 seconds max, though I'd expect most cars to react faster, especially now solar is more common.

[@JulianIlett]

That earth loop check would be different in America wouldn't it? Doesn't their 240V have two live connections with a grounded centre tap?

[@McTroyd]

@@JulianIlett Not an EV owner, but in the US the most common 240v connection type I've seen is two lives, a neutral, and ground (4 conductors). They are most often used for high-power applications (like the clothes dryer in our house). Smaller 240v plugs can be two lives and a ground, but those are less common, and (as Mike said) aren't compatible with EVSEs (especially Tesla).

[@denisouellet6518]

@@JulianIlett In Canada (same as USA), we effectively use the central tap as a Neutral and only bond with the Ground at the main panel. The Ground (or PE) and Neutral are kept separated everywhere else. However, when we use EVSEs made for Europe (I have a couple of those), we simply connect our L1 to your Live (Brown wire), L2 in place of your Neutral (Blue wire) and our Ground to your PE (Yellow/Green wire). There's no verification in those EVSEs that the Neutral is tied or not to the Ground/PE, but the EVSE always check that the Ground is available by leaking some current from the Line. I believe those checks are internal to the EVSE. I have no idea if the embedded charger performs similar checks.

[@denisouellet6518]

@@McTroyd The Neutral from Nema 14-30 (clothes dryer) and Nema 14-50 (range) plugs is never used for EV cars (no idea why Tesla prefers this connector), but the Nema 14-50 is also frequently used for camping VR / camping sites to connect 50A 240V split-phase service (2x 120Vac Lines , 1 Neutral and 1 Ground/PE). Many people over here in Canada/USA can simply use Nema 6-20 (3 prong 20A 240V, no neutral) and Nema 6-50 (3 prong 50A 240V, no neutral) to connect their EVSE (Tesla even offers adapters for those too, but they are less popular).

[@McTroyd]

@@denisouellet6518 Duly noted! Thank you.

[@aaronmdjones]

As a UK electrician, at 2:00 you are correct; coming into contact with any one conductor of an isolated output is safe, whether it's line or neutral. You are also correct that "neutral" doesn't really mean anything on an isolated output; it isn't neutral after all (it isn't referenced to Earth) and only serves as a current path with the other conductor's potential swinging about in relation to it. If you do come into contact with one of the conductors (line or "neutral") of the isolated output, all your body would be doing is forming an equipotential bond between that conductor and true Earth. No current would flow, because there's no complete circuit through that true Earth back to the power supply. This is why we use isolation transformers in bathroom shaver sockets; same principle.

[@aaronmdjones]

Something that just came to mind though, is if you have some class 1 equipment plugged into the power bank as well, and it is sitting on the ground (or you can simultaneously reach that equipment and the line conductor) then that will form a possible return path, making the line conductor suddenly dangerous.

[@edc1569]

@@aaronmdjones this is why you really shouldn’t go connecting Earth to neutral to convince powerbanks to charge cars

[@nexpro6985]

@Julian Ilett it is good to see high current circuits built onto a flammable substrate just like the old days. 😁

[@davidcoates4852]

My 7kW EVSE has a current transformer on my meter tail to prevent the EVSE from drawing more current than the main fuse is rated for. Self regulating, as household demand goes up EVSE consumption goes down.

[@JulianIlett]

Your house fuse should be rated way higher than your car charger. My house fuse is 60A - that's one reason I'm limiting my EVSE to 3.6kW (16A).

[@denisouellet6518]

today's EVSEs implement overcurrent protection, ground fault protection and a thermal protection. your EVSE is like a smart extension cord which self test itself before connecting the mains, for safety reasons. as Julian just demonstrated, the car will still charge with fewer protections.

[@ncot_tech]

The timing and sequencing of the pilot and mains must be pretty relaxed. My PodPoint evse has a schedule timer in it where I have it programmed to start charging at half midnight and then stop at half four (guess which energy supplier I use 🐙). The car has no clue what’s going on and just sits there waiting for the mains to come on.

[@NiHaoMike64]

For measuring response time, you could connect one channel of a sound card to the PWM signal through an attenuator and the other channel to a current transformer. (Or use a scope if you have one, but even the good scopes often aren't too great with slow timebases.)

[@wthornton7346]

Educational and entertaining. Thanks!

[@pr3tty0bnoxious35]

Can you please do a "how to" tutorial on how to make chargers for electric vehicles ?

[@NickNorton]

Decking timber is just what I need for slicing bread. With the routed grooves, you'd get proper through cut slices.

[@gufc6147]

Can you share circuit diagram and program for arduino. I just got my charger blown up and it is expensive here

[@deslomeslager]

So you want MPPT for charging your car? I think it can be done with several NE555 chips. If you use the right 'feedback' (which is in fact the voltage drop over a known resistor, which equals the amps / power) it may be doable. (not saying it will be easy, but I did see an MPPT circuit build with a 555). Maybe it just cannot be done that way, in any case, I am just brainstorming.

[@chuxxsss]

Was thinking the same thing.

[@pohlr1]

You may of mentioned this but the signal is a 1 kHz square wave at ±12 volts making sense for the 12v batteries

[@restfulplace3273]

There are digital potentiometers to use with arduino. Then wifi connection to the arduino. Control the arduino over wifi, or program it with other inputs.

[@flagpoleeip]

It's good that you're willing to sacrifice your electric car to science.

[@JulianIlett]

More of a good workout than a sacrifice!

[@flagpoleeip]

@@JulianIlett I chose my words carefully😀

[@Okurka.]

He's testing out that 7 year warranty.

[@corentinoger]

I'm surprised your car accepts charging with floating neutral, When I got my Zoé, it would refuse charging (both EVSE & granny cable) because my house had bad earth. I could trick it to charge by putting N and PE together in my house (just as a test, of course I installed proper earth). As for the car's reaction time to PWM change, I can confirm it's fast, my Wallbox has the "powerboost" accessory which is remote meter restricting charge to available power (I have a 7kW charger but my mains trips at 9kW). The car always throttle down before the mains trips, even when I tried switching on two 2kW heating fans simultaneously while the oven was on The house meter maxed at 9kW. Clouds can't be that fast, shadow from a low flying fighter jet, maybe.

[@JulianIlett]

The car doesn't seem to care whether PE is connected to N or not. The EVSE is much more concerned about all that earthing stuff. After all, it's not the car that will electrocute you, it's the charger.

[@corentinoger]

@@JulianIlett I assumed it was the car, but as you said, it might have been the Wallbox and granny cable not liking my house electrics.

[@jl9816]

Use a 555 instead of microcontroller for 1khz

[@JulianIlett]

Yes, an EVSE could be as simple as a 555 and two optos :)

[@nightshadelenar]

with this done and working, this could be neat to have riding the electricity cost, where the car would charger at 13A at night, and say, 8A during the day. Or 32A at night and 13A during the day, depending on if it's H/W in or just a plug on the wall.

[@SaSaaVirus]

my evse does 6A to 16A (@240v) 1200-3600 Watts specially bought that one because most campsite have a 8a fuse here in europe. and as a bonus I can charge it with my deltaflow mini (for like 4kilometers of range)

[@m1geo]

My Tesla does not like mains power being present immediately. It reports a charger error.

[@alankingvideo]

Electricuted yourself once when 12 years old, started me thinking. I'm an engineer and have been all my life, and admittedlyelecruted myself with 240v across various parts of my body quite a few times as a child, and probably less as an adult. I have in fact lost count, and only realy remember the ones with burns specifically. altogether must be 50 of more times. and a couple or monitor discharges, and 1 monitor HT cable. Now I know im an idiot, but is this disregard for safety common? I now only work on live equipment with an isolation transformer and rubber gloves, but thats only the last 10 years.

[@asiw]

Fascinating

[@andymouse]

Realy coming together now, great stuff !....cheers.

[@fredflintstone1]

Cheese!!!!!!!!!!!

[@andymouse]

@@fredflintstone1 SQUEAKYPOO'S !!!!

[@fredflintstone1]

@@andymouse I have had a few of those in my time :-)

[@andymouse]

@@fredflintstone1 LOL !

[@stal5861]

I've built my own EVSE after being inspired from your projects. CEE-plug 400V 16A, three phase, with relays. Worked fine when mounted on a wooden board, but now after I put it in a sealed plastic box it overheats and car says "communication error". Works fine when pulling ~5A, but not at 16A. Not easy to fix really.. I want to be able to have it outside in the rain still, so fans and holes is not a great solution.

[@pratikbhagat9028]

Can you kindly guide how are you able to detect stateA stateB stateC as you are using optocoupler. It seems pc817 alike optocoupler. This galvanically isolates the cp pwm from microcontroller to car. But then even if car pulls cp pwm to 9volt stateB how are you able to detect the stateb

[@cagcos]

I just want to simulate a car being plugged in to my charger, would I only need 2.7k resistor between cp and gnd?

[@madprofessor9423]

I am watching your testing and progress with interest. I am planning on making a similar diy EVSE using ESP32 or modify an existing EO Mini Pro 2 as it uses an raspberry pi for it's brain, in conjunction with home assistant that we already use for real-time ish monitoring of energy production and consumption.

[@jay114212]

Awesome work! Would you please share the schematics and ardunio source code?

[@M0LHA]

I wonder how hard it would be to build a basic EVSE tester? Could be useful for projects like this without risking nuking your car

[@Sylvan_dB]

Probably could have used a 555 or even a pair of flip flops for the 1khz :)

[@denisouellet6518]

Always wanted to know if the relays in the EVSE were required... but you should insure switching off the live wires before plugging/unplugging to prevent damaging the connector pins by arcing.

[@JulianIlett]

The relays aren't needed from a functional point of view, but are required to implement safety features.

[@Jlbullivant]

It shouldn’t arc when plugging in as it’s not drawing a current. For unplugging, my car lowers its usage to 0.5kw before unlocking the mechanism to allow the plug to be pulled, so similarly minimal arcing if any should occur. Still not a bad idea to turn off the mains I suppose

[@pepecrisostomo357]

​@JulianIlett very staightforward setup, liked it. What kind of communications protocol are you using with the car, is this the standard in the US?

[@raytry69]

Do you have a clamp current meter? With that you could easily capture a video about the pulse width mod and amperage draw of your car.

[@vernepavreal7296]

Interesting project I am interested in putting a few solar panels and a very small. House battery system on any electric campervan do you think an even more reduced system would be practical? I’d like to avoid repeatedly cycling the vehicles chargingcontactors so as to avoid wear and tear of course Cheers

[@TroyFletcherKeyboards]

Those pens were may favorite, and jlcpcb stopped sending them. Where do you get yours?

[@Friendroid]

They go for over $100 on ebay nowadays, highly collectible

[@TroyFletcherKeyboards]

@@Friendroid Unreal

[@JulianIlett]

No way are they selling for $100! I'd be a thousandaire if they were :)

[@chilledoutpaul]

hi Julian, I think Mike of mikes electrical stuff has got an electric car and in the past has been buying or coming by various electronic modules to take apart and explore. You probably know but if you didn't i thought i would give you a heads up.

[@paulwright5440]

Man you're intelligent

[@edc1569]

I suspect German, Japanese and Korean cars will all behave differently with differences between generations too!

[@joeabad5908]

Nice priject

[@eliotmansfield]

you can of course buy smart solar sensing chargers - so is this just an exercise in trying to do it yourself?

[@JulianIlett]

That's what we do here :)

[@flashback9966]

Looks like a diy Zappi is on the way! But seriously I'm interested to know, what is the PWM relationship to power drawn? My Zappi has a minimum of 1.4kw. Can this be set lower or is it set by the EV?

[@nightshadelenar]

good question, i think its the EVSE that is the limiting factor at high current charging, EVs won't charge at less than 6A minimum. 1.4kW is 6A @ 240V, which makes sense.

[@flashback9966]

@@nightshadelenar Maybe I need a lithium charger, charging a 'slave' lithium battery. Then when it''s cloudy I can charge this battery slowly and then dump this energy in 6A steps. Could be useful in winter when solar is low.

[@volkhen0]

My car has 3 setting for charging current which works independently of EVSE. Minimum I can set is 500W. It’s 6 amps on EVSE and “minimum” in the car settings.

[@brianfrancis7145]

Can you decrease the wattage to 500 watts. This would allow charging on a cloudy day without drawing anything from the grid.

[@nightshadelenar]

minimum is 1.4kW, so likely a cloudy day will see some grid draw.

[@benetra]

@@nightshadelenar The minimum shown in the video is indeed 1400W. In my experience however, the minimum is 10% pulse width, which corresponds to 5A, which at 240V equals 1200W. I have no idea if in practice the EVSE can "convince" the car pulling less by further decreasing the PWM. Maybe some cars may be pull even less than 5A with a pulse width less than 10%... or they will stop charging altogether if pulse width is below 10%.

[@LaserFur]

The EV connector is not rated for inrush current during connection. So connect to the car first.

[@fredflintstone1]

Nice video so a good cheap system, does this mean your EasyEVSE is redundant ????? :-)

[@JulianIlett]

When I start using house mains, the relays will be needed for safety. They need to cut the mains if there are CP signal irregularities or ground faults.

[@JamieJones1985]

Does the car care if the 1khz has the -12v part? I've DIY'd an EVSE but used an ATX for 12v and -12v. I've DIY'd the car too, but never thought to check if the OBC I used would work with just 0-12v on the CP. I have a similar aim with the excess solar on the next iteration, will also be using your isolated DCDC idea to get -12v to make it smaller.

[@JulianIlett]

I'm told the Nissan Leaf doesn't require the -12V part of the signal. As for other vehicles, I don't know.

[@tasmedic]

Couldn't you make things cheaper and simpler by using a 555 timer (or even 2 transistors) configured as an astable multivibrator?

[@twotone3070]

He wants to be able to dynamically alter the mark-space ratio, so I don't know if that is possible.

[@georgemorris8766]

You didn't have a cloudy day because you were not working with your solar panels!

[@Markus_V7755]

Is that waterproof?

[@JulianIlett]

No

[@nickruddle1528]

LInk?

[@JulianIlett]

Done!

[@PhoneVidoes]

Still seems a very overly complicated way of doing things when I do it all very simply with a Viridian EPC and a variable resistor on the IC connction.

[@David_11111]

Yay any magic smoke ???

[@JulianIlett]

Not yet :)

[@dougle03]

Where would that come from exactly? The mains is passed straight through....

[@hunter00047]

Without ref to ground, does that mean a rcd would be useless? ⚡⚡👍😄

[@mikeselectricstuff]

Yes.

[@hunter00047]

@@mikeselectricstuff Thanks sometimes I think we would be better off without earthing and make everything double insulated, except for lightning protection. 👍

[@Sylvan_dB]

No vehicle has a ground reference. Some attempt to deduce a ground reference by checking voltage and/or current with the ground pin.

[@hunter00047]

@@Sylvan_dB it will have ground reference if you touch the vehicle?? ⚡

[@Sylvan_dB]

@@hunter00047 you are not a reference, but merely a potential path. A reference is a known source of truth.

[@Fran55on]

Hi! I usually like Julians videos a lot, but this time I had to down vote it due to showing a dangerous circuit. DO NOT EVER MAKE A EVSE THAT CAN PUT POWER ON THE VEHICLE PLUG WHEN IT IS NOT CONNECTED TO THE VEHICLE!!! (Aka without any relays.) I will report this video to KZbin as a dangerous video.

[@JulianIlett]

With that logic, any video about anything remotely heavy is dangerous - because you might drop it on your foot.

[@Tekwyzard]

Hopefully you'll also report every youtube video that features the use and/or construction of electrical extension cords, because that's exactly what Julian made, albeit a fancy one with some extra conductors for control signals, but it's just an extension cord, like many millions of others, all without any relays to control the pass-through of the electricity. About the only real danger (like with any other extension cord) is 'Darwin Award' candidates sticking screwdrivers and such into the fully shrouded socket.

[@denisouellet6518]

He's possibly missing few disclaimers here and there (e.g. DON'T TRY THIS AT HOME), but there's still valuable teaching out of this video. Go watch some ElectroBOOM videos before reporting Julian.

[@Okurka.]

KZbin won't even remove videos featuring microwave transformers.

[@dougle03]

Not in the business are you? Your reaction is little over the top. This video is entirely in keeping with the content on Julians channel. Also, the EVSE plug is designed to protect the terminals from both humans and damage, so where is the great risk you refer to?