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Chargers being turned off

Posted: Thu, 22 Oct 2020, 13:58
by Paul9
Hi people,

I thought I could remember someone on these forums mentioning that battery chargers do not like being turned off when they are charging at full pace. I checked with Phil Gel from Gelco Services and he confirmed the above.

I have had to turn chargers off when they are charging at full pace and have had nothing go wrong. That may have been just good luck!

I have both a Residual Current Device and overload protection for my chargers but they don't protect against me turning the charger off or the brief blackouts that my place experiences occasionally.

Could there be anything I could put/wire between the power source and the charger that could protect the charger against blackouts or times when I need to turn the charger off?

Thanks in advance
Paul

Re: Chargers being turned off

Posted: Fri, 23 Oct 2020, 10:52
by coulomb
Paul9 wrote: Thu, 22 Oct 2020, 13:58 Could there be anything I could put/wire between the power source and the charger that could protect the charger against blackouts or times when I need to turn the charger off?
There is nothing you can put in the EVSE; the damage occurs internal to the charger, as far as I know.

If you need to turn off charging: if you have a type 1 (J1772) plug, you can press the button, which will safely ramp the charge current to zero, and either then turn off the supply, or unplug the vehicle. Alas, type 2, now by far the most common system, doesn't have the button. [ Edit: however, most type 2 vehicles (certainly the Zoe) would have a "plug release" button somewhere on the car which achieves the same purpose. ]

If the vehicle can terminate the charge, then that will also ramp the current to zero safely. Sadly, I'm not aware of any easy facility for doing that (but I don't know type 2 vehicles very well).

Some EVSEs allow you to change the charge current to different values with a button or similar; changing to the lowest charge current possible will presumably minimise any potential damage.

Finally, if all else fails, you just have to switch off the supply (or in the case of a blackout, supply will be cut and you can't do anything about it), and trust in the design of the On Board Charger. Sadly, the on board chargers of early models (iMiEV, Leaf) have known problems with small capacitors blowing up, which may be exacerbated by frequent supply interruptions. Hopefully, manufacturers have learned from these mistakes and are designing more robust, generally and in particular in response to the supply being suddenly cut off.

All the above refers to AC charging. DC charging really has to be terminated by the charger (which in the case of DC is in the external charger, possibly in an equipment room separate from the charger unit with the charge handle. In the case of supply interruptions during DC charging, hopefully the DC charging equipment is designed for industrial robustness, and can absorb the prodigious energy that would be stored in the magnetics of a potentially very powerful charger.

Re: Chargers being turned off

Posted: Fri, 23 Oct 2020, 14:23
by antiscab
on my zoe, pressing the plug release button on the car shuts down charging gracefully

given latching the plug is part of the type 2 standard, this should be common to all cars that take a type 2 plug

Re: Chargers being turned off

Posted: Fri, 23 Oct 2020, 17:52
by shallowal
CCA2 uses a similar signalling protocol to type 1 chargers. A simple NC (normally closed) switch across a 330ohm resistor in series with the pilot signal from the vehicle will cause the vehicle charger to shut down and the security latch to disable so that the plug can be removed safely when the switch is opened (ie pressed).
ref: https://en.wikipedia.org/wiki/SAE_J1772 ... ircuit.gif

The security latch prevents the plug being removed until the vehicle allows.
Tesla chargers have a 'soft' switch incorporated, I dont know why it is not a standard fitting for all CCS2 charging handles.

Re: Chargers being turned off

Posted: Sat, 24 Oct 2020, 08:58
by coulomb
shallowal wrote: Fri, 23 Oct 2020, 17:52 CCA2 uses a similar signalling protocol to type 1 chargers.
If you mean CCS2, CCS stands for Combined Charging System (i.e. DC as well as AC). Type 2 AC ports use a similar signalling system yes, but the proximity pin has a different use.
A simple NC (normally closed) switch across a 330ohm resistor in series with the pilot signal from the vehicle will cause the vehicle charger to shut down and the security latch to disable so that the plug can be removed safely when the switch is opened (ie pressed).
The "proximity" pin is different, and on type 2 is used to indicate the current carrying capacity of the charge cable (which is usually not tethered).
That reference is for J1772 (type 1). This page is for type 2: Type 2 connector. They mention a proximity pilot (PP) on one pin, but there is no detail. There are tables of the resistors required for various cable currents, e.g. https://canze.fisch.lu/resistors-is-charging-cables/ .

Re: Chargers being turned off

Posted: Sat, 24 Oct 2020, 09:00
by coulomb
antiscab wrote: Fri, 23 Oct 2020, 14:23 on my zoe, pressing the plug release button on the car shuts down charging gracefully

given latching the plug is part of the type 2 standard, this should be common to all cars that take a type 2 plug
Brilliant! I'll edit my post to include that.

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 06:32
by 4Springs
Paul9 wrote: Thu, 22 Oct 2020, 13:58 I have had to turn chargers off when they are charging at full pace and have had nothing go wrong. That may have been just good luck!
Me too.
Lately, I've been turning power outlets on and off with a timer to charge during off peak times. I've done this with an Outlander EVSE, a Gelco EVSE (both type 1), a Kona EVSE (Type 2), a TC Charger charger and an older Chennic one. I'm cycling power daily, and have been for some time.
I've also advised others to go to the Time of Use electricity tariff and install a timer. My reasoning is that this makes it very simple to use off peak electricity. When you plug your car in to charge, plug it into the off-peak outlet. Or if you want to charge NOW, plug it into the other outlet, which is powered all the time. But perhaps I should be advising that people use the timer in their car (when one exists). I have avoided using this myself, as it is complicated to use. At least in the Kona, which is the only car we own that has one.

Paul - what charger are you using? Is it on your conversion?

I'd be interested to know whether the advice to not turn a charger off 'at the wall' applies when they are delivering lower current. For instance when my TC Charger is in its final charging stage, which takes quite a few hours but delivers very little current.

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 09:13
by coulomb
4Springs wrote: Mon, 26 Oct 2020, 06:32I'd be interested to know whether the advice to not turn a charger off 'at the wall' applies when they are delivering lower current. For instance when my TC Charger is in its final charging stage, which takes quite a few hours but delivers very little current.
The main problem is the energy in the PFC ("Power Factor Correction") stage. Its current varies as a sine wave of course (very close to the AC input current), but the peak value depends on the load (i.e. it's close to proportional to the charging current).

So I would say that the risk is proportional to the charging current. The lower charging current, the lower the risk is.

[ Edit: the energy stored in an inductor is ½LI², so it's proportional to the square of the current. So lower current is much lower risk. 10% of maximum current means 1% of maximum stored energy. ]

BTW, Elcon/TC chargers are renowned for their spectacular arcing when the power lead is disconnected under load. I believe that protective devices slowly degrade with each under-load disconnection, so the risk of failure increases over time.

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 09:50
by Paul9
Thanks to Mike, Matthew, Allan and Christopher.

You guys talk about proximity switches or buttons and soft stops but unfortunately this problem is on my Swift conversion. No buttons etc here!

98% of my charging is done at home. To put it in highly technical terms (highly technical for me anyway!) extension lead is plugged into timer which is plugged into power point. RCD and circuit breaker thingy is plugged into extension lead. Charger is plugged into RCD thingy (told you it is technical). This is when I have the occasional problem with blackouts. The blackouts may only last 10 seconds but sometimes longer.

To answer Christopher's question I am using a KPES 2000 charger. Well, actually, I have two of them - one in the boot and one under the bonnet.
The one in the boot:
water-cooled-charger.jpg
water-cooled-charger.jpg (1.45 MiB) Viewed 1647 times
The square can just to the right of the charger in the picture is a highly technologically advanced water cooling system I invented (patent pending). When I first installed these chargers I noticed they don't get hot uniformly over their surface. While the charger is charging, the right hand side gets much hotter than the left hand side or the top surface. I filled the can 80% full of water and placed a thermometer with a probe in it to ensure I would measure the temperature of the water not the can. On the day of the test, the air temperature was 16C and the temp of the water was 13C. The charger then spent two hours charging. When it finished charging, the temp of the water had gone from 13C to 28C.

When I am charging at a public station I use both chargers through a double adapter. One double adapter for J1772 stations and one double adapter for Tesla Destination chargers or Type 2 chargers. I assume Type 2 adapters won't work in CCS2 charging stations?

Tesla Destination double adapter:
Destination charger.jpg
Destination charger.jpg (1.27 MiB) Viewed 1647 times
Looks like I will just have to keep my fingers crossed when charging at full pace. I believe that when the charger is in Constant Voltage stage and amps are decreasing, then the risk of damaging the charger is significantly decreased when the power is turned off.

Thanks for your advice guys.
Regards
Paul

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 10:16
by jonescg
So the other pins are live when plugged in?!

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 10:29
by coulomb
jonescg wrote: Mon, 26 Oct 2020, 10:16 So the other pins are live when plugged in?!
? Those would be sockets, as in any extension cord. Sockets are designed to be safe when live.

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 10:31
by coulomb
Paul9 wrote: Mon, 26 Oct 2020, 09:50 I assume Type 2 adapters won't work in CCS2 charging stations?
Yes. Only the control pins of the AC part are used. They probably don't even have holes for the phase pins, so you couldn't even plug in an AC type 2 plug.

Re: Chargers being turned off

Posted: Mon, 26 Oct 2020, 12:03
by jonescg
Oh good - couldn't tell from the picture

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 06:32
by shallowal
coulomb wrote: Sat, 24 Oct 2020, 08:58
shallowal wrote: Fri, 23 Oct 2020, 17:52 CCA2 uses a similar signalling protocol to type 1 chargers.
If you mean CCS2, CCS stands for Combined Charging System (i.e. DC as well as AC). Type 2 AC ports use a similar signalling system yes, but the proximity pin has a different use.
You're right, I find the term "type 2" to be a very indistinct means of discussing EV plugs so normally use the CCS label.
A simple NC (normally closed) switch across a 330ohm resistor in series with the pilot signal from the vehicle will cause the vehicle charger to shut down and the security latch to disable so that the plug can be removed safely when the switch is opened (ie pressed).
The "proximity" pin is different, and on type 2 is used to indicate the current carrying capacity of the charge cable (which is usually not tethered).
The proximity pin seems to have the same function in the type 2 protocol. I modified my own Type 2 plug with a switch and resistor and it works very well in shutting down the charge current and releasing the security latch on the connector.
ref: https://en.wikipedia.org/wiki/SAE_J1772 ... ircuit.gif
That reference is for J1772 (type 1). This page is for type 2: Type 2 connector. They mention a proximity pilot (PP) on one pin, but there is no detail. There are tables of the resistors required for various cable currents, e.g. https://canze.fisch.lu/resistors-is-charging-cables/ .
The usual way the charge current is determined is by way of a PWM signal on the Control Pilot line, rather than resistors on the Proximity Pilot line. There is a good explanation on page 18/19 here:
https://www.researchgate.net/publicatio ... cal_Report

The switch works well on my OpenEVSE and Tesla M3 setup.

The brief discussion on page 21 of the P1901 powerline communications standard is perhaps the reason so many non-Tesla have trouble with the current Tesla HPWC wall chargers.

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 07:13
by brendon_m
I thought that the type 1 AC connector (commonly called J1772) has the exact same control interface as the type 2 AC connector (commonly called mennekes).
They both use the J1772 standard (which is for communication not plug shape).

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 07:57
by coulomb
shallowal wrote: Tue, 27 Oct 2020, 06:32 The proximity pin seems to have the same function in the type 2 protocol. I modified my own Type 2 plug with a switch and resistor and it works very well in shutting down the charge current and releasing the security latch on the connector.
Huh. I find a fixed resistor in my type 2 to type 1 adapter cable (I have a type 1 Leaf). I wonder if any sudden change in the resistance will trigger a termination of charge.
ref: https://en.wikipedia.org/wiki/SAE_J1772 ... ircuit.gif
That reference is for J1772 (type 1). This page is for type 2: Type 2 connector. They mention a proximity pilot (PP) on one pin, but there is no detail. There are tables of the resistors required for various cable currents, e.g. https://canze.fisch.lu/resistors-is-charging-cables/ .
The usual way the charge current is determined is by way of a PWM signal on the Control Pilot line, rather than resistors on the Proximity Pilot line.
The control pilot signal (which is the only pilot signal for type 1) specifies the current capability of the EVSE and its wiring. The proximity pilot (as it's called in type 2) indicates the current capability of the charge cable. In type 2, the cable is usually not tethered (Tesla is an exception), so the cable might be lower current capability than the EVSE. So in type 2, they seem to take the lower of the two limits, and work with that.
There is a good explanation on page 18/19 here:
https://www.researchgate.net/publicatio ... cal_Report
At a quick glance, that doesn't seem to address the type 2 differences. A lot of publications are US-centric, where they have only type 1.
The switch works well on my OpenEVSE and Tesla M3 setup.
I'll admit that this surprises me. But pushing the switch presumably increases the resistance from the proximity pilot pin to earth, which would indicate a lower cable current capability. Perhaps the Tesla stops if the resistance is greater than a certain amount (220 Ω corresponds to 32 A, for example). Or maybe Tesla got that part of the specification wrong too.

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 11:45
by shallowal
coulomb wrote: Tue, 27 Oct 2020, 07:57
Huh. I find a fixed resistor in my type 2 to type 1 adapter cable (I have a type 1 Leaf). I wonder if any sudden change in the resistance will trigger a termination of charge.
I dont think the 'change' is the trigger, it's the resultant voltage levels that are measured.
ref: https://en.wikipedia.org/wiki/SAE_J1772 ... ircuit.gif
That reference is for J1772 (type 1). This page is for type 2: Type 2 connector. They mention a proximity pilot (PP) on one pin, but there is no detail. There are tables of the resistors required for various cable currents, e.g. https://canze.fisch.lu/resistors-is-charging-cables/ .
The signalling is the same between the 2 plug types (1 & 2).
The control pilot signal (which is the only pilot signal for type 1) specifies the current capability of the EVSE and its wiring. The proximity pilot (as it's called in type 2) indicates the current capability of the charge cable. In type 2, the cable is usually not tethered (Tesla is an exception), so the cable might be lower current capability than the EVSE. So in type 2, they seem to take the lower of the two limits, and work with that.
Yeah, that makes sense in an environment where the cable may not be part of the chargers equipment, eg non-tethered. so both the cable and the charger can limit the charge rate to suit their capabilities.
I have visited a lot of chargers in the NSW/ACT region since I bought the car last year, and have never come across an untethered charger. Admittedly the vast majority of chargers are Tesla ones, but chargepoint and others all seem to be tethered.
There is a good explanation on page 18/19 here:
https://www.researchgate.net/publicatio ... cal_Report

At a quick glance, that doesn't seem to address the type 2 differences. A lot of publications are US-centric, where they have only type 1.
It seems to me that the only difference between type 1 and 2 chargers is the shape of the plug and that Type 2 supports 3 phase. As I mentioned before, I wonder whether the problem with the newer Tesla AC chargers not supporting non-Tesla's is that those other vehicles are not supporting the P1901 protocol. The earlier Tesla AC chargers had the 'legacy' mode switch which allowed the older voltage sensing protocol to work.
The switch works well on my OpenEVSE and Tesla M3 setup.
I'll admit that this surprises me. But pushing the switch presumably increases the resistance from the proximity pilot pin to earth, which would indicate a lower cable current capability. Perhaps the Tesla stops if the resistance is greater than a certain amount (220 Ω corresponds to 32 A, for example). Or maybe Tesla got that part of the specification wrong too.
It's yet to be proved in any sense that Tesla has got anything wrong. All the M3's in Australia/UK/Europe happily work with anyones AC charger, The reverse does not seem to be as certain and I for one would love to know why this is so.

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 14:00
by coulomb
shallowal wrote: Tue, 27 Oct 2020, 11:45 I have visited a lot of chargers in the NSW/ACT region since I bought the car last year, and have never come across an untethered charger. Admittedly the vast majority of chargers are Tesla ones, but chargepoint and others all seem to be tethered.
Some of them have a cable provided, but the cable isn't fixed to the charger (what I mean by tethered). So the cable can be removed; this is good, because I need to remove the cable for my type 1 Leaf. (I don't want to butcher my type 2 socket, by sawing off 11 mm of plastic.) For example this one at Toombul shopping centre, Brisbane:



[ Edit: I'm pretty sure that all the AC chargers on the Queensland Electric Super Highway are non-tethered. Example: Gold Coast Air Port below. ]


It seems to me that the only difference between type 1 and 2 chargers is the shape of the plug and that Type 2 supports 3 phase. As I mentioned before, I wonder whether the problem with the newer Tesla AC chargers not supporting non-Tesla's is that those other vehicles are not supporting the P1901 protocol.
By P1901, do you mean the ethernet over power lines protocol, per this Wikipedia article? That doesn't seem to be relevant to this discussion.

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 16:11
by shallowal
coulomb wrote: Tue, 27 Oct 2020, 14:00
By P1901, do you mean the ethernet over power lines protocol, per this Wikipedia article? That doesn't seem to be relevant to this discussion.
Yeah, it does seem strange when you call it ethernet over powerlines, but if you expand your thinking to data transmission over powerlines it starts to make more sense. It was proposed as a standard for CCS charging in 2012, but I cant find any positive confirmation anywhere as to whether it is actually used or even ratified for use.
It would be really useful to have access to a charger and EV from the power network for monitoring and control both for personal use and for the wider electricity network to assist in managing the network.

Re: Chargers being turned off

Posted: Tue, 27 Oct 2020, 19:24
by coulomb
shallowal wrote: Tue, 27 Oct 2020, 11:45 It seems to me that the only difference between type 1 and 2 chargers is the shape of the plug and that Type 2 supports 3 phase.
I've had a bit of time to read the article you linked to, and I'm starting to agree with you. The two values type 1 uses for the switch (150 and 480 ohms) seem to be carefully spaced between values used to indicate the current capability of the charge cable (150 Ω is between 100 and 220 Ω, and 480 Ω is between 220 and 680 Ω). Maybe the cable current capacity even works for type 1 on-board chargers (if they bother to implement the full specification). But my guess is that type 1 chargers only implement the switch functionality.

So you could be correct in claiming that the Tesla EVSE is correct to respond to the switch as you have found. Though it should also respect the current capacity "data" if the measured resistance falls near the appropriate values (100 / 220 / 680 / 1500 ohms, and perhaps also open and short (<50 Ω) circuits (in the latter case, if it's capable of drawing more than 63 A AC).