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Discussion Starter #1
Hi there,
I’d be interested to hear if anyone has a MyEnergi Zappi charger and if they have had any charging issues.
We have a Zappi (and PV Solar) and use it to charge our Smart forfour EQ.
If you don’t know the Zappi, it essentially allows you to charge the car on the excess energy from a renewable source that would otherwise be going out to the grid.
It has various charge modes, one of which (eco +) allows you to charge from the excess solar only, so if the sun goes in and the excess drops below a certain level (defined in an industry wide charging spec) the charging is paused.
Our Smart doesn’t seem to like this pause, reports an error on the dash, tells us to take it to a workshop and will not start for ~15 mins. Mercedes have had it on their diagnostics and tell us nothing is wrong with the car.
We don’t have any issues in the other charging modes offered by the Zappi (a 7kWh ‘fast’ and an eco where the PVs are boosted by the grid when the sun goes in so charging is not paused).
The good people at MyEnergi tell me they have not seen a problem with the cars they have tested with (Jag, Renault, Nissan, Tesla).
Mercedes/Smart don’t seem to be interested in having a dialog about the problem which is inexcusable given we have just bought a new car off them – it sound from the only response that we have had from them that they just don’t understand the problem and seem to think I have some heath-robinson system where I’ve directly connected the car to the PV panels!
They have now said the problem is closed and they are not willing to talk further – terrible customer service.
I’d be interested in hearing any experiences of others, positive or negative in this area.
Many thanks,
Chris
 

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We have just got a Hyundai Kona and I got a Zappi.

I have the Zappi on eco + with a boost timer set to run at 01.30 for 7 hours.

It worked fine last night, but before I left it I cycled through Fast & eco which paused the charging and it didn't serm to cause any issue.

We are in the process of getting solar & battery storage and will probably set the car to charge during the day with the excess generation after the battery storage is charged.

My impression of Zappi is that it works well. Sounds like a car issue.

Hope you get it sorted out.
 

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Discussion Starter #3
Thanks very much chromium.

I suspect it's the Smart at fault too, obviously I know nothing about the charging software on there but it seems to stop talking to the Zappi after a few pauses (because of breaks in the sun) - I suppose Smart/Mercedes thinking is that if this happens x times in y period of time then the charger could be faulty and I'm locking down to protect myself.
I suppose you must have used eco+ on days that are less than 100% sunshine this time of year, so yes that's another car that doesn't have this issue.

Anybody else?
 

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Mercedes dealer probably has no useful option open to them to alter the software, you can try pushing the problem further, but essentially you probably have to live with what you have got.

You can adjust the Zappi settings so that it switches off with variable amounts of solar power and various lengths of time. In summer I run at nearly 95% solar, but in spring and autumn I reduce down 50% and longer duration with less solar power.
 

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I've built an EVSE that does much the same as the Zappi, and ran into the problem you are describing when trying to charge my Prius Plug-in. The issue seems to be that the Zappi (and my home brew EVSE) may be trying to do something that isn't documented in the J1772 protocol, continuously vary the duty cycle of the Control Pilot in order to vary the charge current from its 6 A minimum up to the maximum allowable from either the installation or the car charger.

I got around this by using a switched approach, where the charger initially turns on when exporting more that 1500 W, at the minimum charge rate of 6 A. It stays at this charge rate unless the export changes to import when it turns off, killing the Control Pilot signal which causes the car charger to turn off safely. If the export again increases to 1500 W the charge point turns on again at 6 A, and if this isn't enough to use the excess PV generation it shuts down, increases the charge current by 2 A and starts up again. It will continue to briefly shut down and restart at a new current with any significant change in excess generation. Mine does this check and cycle every ten minutes, simply because I found that to be a reasonable compromise between getting the best use from the excess PV generation in variable conditions, not importing too much grid energy and keeping the car charger happy.

I've now got a BMW i3 and this seems to work OK with this charging profile, but I may go back to my original code that allowed a continuously variable duty cycle on the Control Pilot, as I've been told that the i3 charger will change current on the fly, unlike the charger in the Prius. If this works I'll report back here.

I suspect that it's very much down to the interpretation of the J1772 signaling protocol by each manufacturer. As far as I could tell, the charger in the Prius only checked the Control Pilot duty cycle once, when first starting to charge. I believe the Zappi relies on the car charger checking the duty cycle continuously throughout the charge, something that doesn't seem to be documented in the specification for the charging interface as far as I can tell.
 

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Discussion Starter #7
Hi Jeremy,

I’m an EV novice so just starting to put this together from things I’ve read and what has been said here.

I don’t think changing the duty cycle/current is our issue as when charging on Zappi’s eco mode (i.e. varies current based on how much excess energy there is but never allows it to go below the minimum, taking this from the grid if needed) we have never had an issue. It’s only when the charging is paused in eco+ mode, multiple times I think, we have the issue with the Smart.

It seems that others Zappi owners I’ve talked to don’t have any problems when charging in eco+ mode.

Many thanks.
 

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The issue seems to be both a lack of clarity in J1772, regarding the signalling protocol, plus differences in the way that the protocol has been interpreted by different manufacturers, I believe.

J1772 wasn't ever envisaged to enable on-the-fly charge current changes, although it's a happy accident that some implementations of it do allow this without a hitch. The sequence of events to initiate a charge is broadly this:

The EVSE measures the resistance between the Proximity Pilot terminal and PE to determine the charge cable current capacity (if the charge point has a socket). The value of this resistor inside the Type 2 connector determines the maximum current that the EVSE will make available.

The EVSE puts a 1 kHz signal, at +/- 12 V on to the Control Pilot terminal, with a duty cycle that sets the maximum current that the EVSE can deliver (this can vary from a minimum of 6 A up to a maximum of 80 A, although few charge points exceed about 30 A in practice).

The vehicle senses the duty cycle of the 1 kHz Control Pilot signal and does two things in the first instance. It will load the Control Pilot positive going signal with a resistance of 2.74kΩ and it will load the negative going signal with a diode to limit it to ~ -0.7V. The EVSE interprets these conditions as being that the vehicle is plugged in and that the cable integrity is OK (that's what the diode shorting the negative going bit does - just for safety).

Next the vehicle will measure the duty cycle and set its internal charger to not demand more current than the EVSE has signalled.

When the vehicle is ready to charge, it will load the Control Pilot positive going signal with a resistance of 882Ω, to signal to the EVSE that it is ready for power. The EVSE will detect this and turn on the contactor to supply power to the vehicle charger.

If the Control Pilot negative going signal increases (in a negative direction) beyond about -1 V, the EVSE will turn off the contactor, and flag up a cable fault condition (this indicates that the Control Pilot isn't being correctly loaded, and protects against something like the connector being dropped in a puddle, where both the positive and negative going parts of the Control Pilot would be loaded more or less equally by the conductivity of the puddle).

If the Control Pilot positive going loading changes from 882Ω to 2.74kΩ the EVSE will interpret that as a request to end the charge, and will turn off the contactor and remain in the vehicle connected condition. Under this condition the connector can be unplugged as there will be no current flowing through it.

I've left out the connector lock functionality, but that's implemented by the vehicle and/or the the EVSE when the charge commence condition is detected. For Type 1 connectors there is also another switched resistance on the Proximity Pilot, at the vehicle end, that is generated by the release catch and signals the vehicle to terminate the charge immediately.

From the above it's pretty clear that there isn't a requirement to continuously monitor the duty cycle of the Control Pilot, only a requirement to measure it at the initiation of the charge. That seems to have been the original intent behind using this method of single wire signalling, but it's clear that some vehicle chargers (probably most of them now) do continuously measure the Control Pilot duty cycle and can vary the charge current on-the-fly.

All vehicle chargers should be OK with the EVSE stopping the charge and then restarting it. What they should do is detect the loss of charging current, but keep the request for charge load (882Ω) between the Control Pilot and PE, provided that the Control Pilot signal is still present. If the Control Pilot signal is lost, then the vehicle should shut down its charger and wait for it to come back up, whilst loading the Control Pilot terminal with 2.74kΩ for the positive going part and with a diode to PE on the negative going part. This then signals to the EVSE (when it comes back up) that a vehicle is safely plugged in, with no cable faults and is ready to accept a charge. From then on the vehicle charger should just go through the normal charge start sequence.
 

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From the above it's pretty clear that there isn't a requirement to continuously monitor the duty cycle of the Control Pilot, only a requirement to measure it at the initiation of the charge.
J1772 has such a requirement in clause E.1(j):

The pilot signal shall be monitored, and charge current adjusted accordingly, continuously during the charge process.
If pilot signal is lost or the pulse width goes outside of the allowable range, the EVSE must terminate the charge
process by opening the main contactor and turning off the pilot oscillator. The EVSE should also display the fault
condition.


Then in clause E.2, Table E.1:

Transition: 11
Initial Condition: State=C or State=D OSC=on
EVSE response time:
EV/PHEV response time: 5s max.
Condition: Change in pilot duty cycle


(I am quoting the 2012 edition).

The same 5sec response time appears in EN61851-1 (2010) in Table A.7. for manufacturers who claim conformance to European rather than SAE standards.

Quite likely it wasn't in the very earliest J1772 versions, but any recent EV should be doing this.

Stopping and starting the charge on the other hand is more tricky. It's quite clear that the EVSE is allowed to terminate the charge, and there's this in J1772 Table E.1 Note 14:

14. State B1 is used by the EVSE to indicate that the EVSE is not ready to supply energy. State B1 may be used by the
EVSE to maintain the current charge session during load management, fee transaction, or other events. This state
may last for an extended period of time. The EV/PHEV may enter a sleep mode during this state and wake upon
detection of the EVSE turning on the oscillator and entering State B2.


However, there's nothing to say that the car has to start charging as soon as the EVSE offers it power - the car is certainly entitled to require a manual start, to apply its own timer, decide it doesn't actually need a charge etc. But putting up a fault message in the dash in this condition is, IMO, not correct.
 

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I'm surprised that Zappi says it works with the Renault ZOE, IIRC my ZOE wouldn't restart without intervention if a charge was stopped. I'm not surprised that some cars can't.
The Zappi has known issues with the Zoe, and a specifica compatibility mode to allow it to work. This is listed in the manual and would be worth trying for the smart car as well.

I think what it does is keep the charging session open, but with no current allowed rather than stopping and starting the session, but that's purely based on what the manual implied when I read through it.
 

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Discussion Starter #12
I have an update on this issue if anyone is interested ...

We recently had another example of the Smart refusing to start/dashboard warning which caused my wife a great deal of inconvenience, so we booked it into the Smart/Mercedes dealer again.

This time they tell us they have found a Battery Management related fault code (P0AF81C).
They say it wasn't apparent last time it was on the diagnostics as it needs to occur several times before its flagged up as an issue.
They tell us that they need to get some specific tools in to allow them to detach the HV battery in order to fix the issue.

So it ‘looks’ like they have admitted to or found an issue with the Smart – but they are unable to give me any real specifics – I'll post again with any progress.
 

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I have just had a \Zappi installed. Works exactly as expected in Fast and ECO mode. However in ECO+ mode there seems to be a problem. If I plug my Renault Zoe (ZE40 R110) in when there is cloud and generating less than 1.4KW the Zappi says "waiting for surplus" as expected. It starts up OK when the surplus is greater than 1.4KW so no problem. However when the cloud comes back and generation fall below 1.4KW or lower the charger just tops up with the grid to maintain 1.4KW and never pauses. I have had to basically stop the charge and pull out the plug to get it back into "waiting for surplus" again. Additionally if I stop the charge and don't pull the plug out the charger says "waiting for EV" and immediately restarts even if the generation is say 0.5KW.

Is this a known issue or is it me ?? If it is an issue is there a fix anyone knows about. I have a call into MyEnergi but the response is very slow !!
 

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It depends on what the % is set to if 100% it should not take any grid, if set any lower some of the grid will be used depending on the % setting
I had it on 100% green so it wasn't the problem. After more fiddling it seems it was the delay setting. When installed it was set to 30secs. I tried increasing it but eventually found it only worked correctly when I reduced it to the minimum 5secs. Now the charger pauses and goes into "waiting for surplus" correctly.
 

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Thanks very much chromium.

I suspect it's the Smart at fault too, obviously I know nothing about the charging software on there but it seems to stop talking to the Zappi after a few pauses (because of breaks in the sun) - I suppose Smart/Mercedes thinking is that if this happens x times in y period of time then the charger could be faulty and I'm locking down to protect myself.
I suppose you must have used eco+ on days that are less than 100% sunshine this time of year, so yes that's another car that doesn't have this issue.

Anybody else?
Hi, have an issue with my egolf.."pilot problem" error message or "unknown cable", in any mode charging mode ..
....again Zappi mentions it is the car whereas VW doesn't think theres an issue. What's confusing is that the car charges with other chargers...would be good to get it sorted...
Thanks very much chromium.

I suspect it's the Smart at fault too, obviously I know nothing about the charging software on there but it seems to stop talking to the Zappi after a few pauses (because of breaks in the sun) - I suppose Smart/Mercedes thinking is that if this happens x times in y period of time then the charger could be faulty and I'm locking down to protect myself.
I suppose you must have used eco+ on days that are less than 100% sunshine this time of year, so yes that's another car that doesn't have this issue.

Anybody else?
Hi, I seem to have compatibility issues with my eGolf. Keep on getting the following error messages, regardless of the charging mode "pilot problem", or "unknown cable". Zappi is implying it's because of the car battery setup whereas VW says the is fine. The car obviously charges with 3.6 kw chargers...would be nice to get it sorted.
 

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Hi, have an issue with my egolf.."pilot problem" error message or "unknown cable", in any mode charging mode ..
....again Zappi mentions it is the car whereas VW doesn't think theres an issue. What's confusing is that the car charges with other chargers...would be good to get it sorted...


Hi, I seem to have compatibility issues with my eGolf. Keep on getting the following error messages, regardless of the charging mode "pilot problem", or "unknown cable". Zappi is implying it's because of the car battery setup whereas VW says the is fine. The car obviously charges with 3.6 kw chargers...would be nice to get it sorted.
Have you called myenergi tech support and been told its the car?
My e-Golf chargers ok in fast mode and with the boost timer. Most F the time its fine in eco+ as well, but now it's autumn I'm only using fast mode overnight.
There are a few issues I've read about with the e-Golf but not with a pilot problem that I remember.

Myenergi are saying that the car manufacturers aren't sticking rigidly to the protocol and it is causing them all sorts of issues.

In the Zappi V1 firmware the VW cars were OK. They did have to make some changes but they got it sorted. When myenergi upgraded their firmware to version 2 there were many issues introduced. The e-Golf is one of the last cars they are working on and I'm expecting they will get it running smoothly at some point.

Is your local VW garage being helpful? Mine were very good when we had issues early on and checked for updates, checked with VW UK etc. It might be worth pressing them for any updates. We have had surprising things occur that needed a software update, the sos system flashing up and speaking error messages repeatedly while driving along was the one I remember clearly.
 

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No, the installer has been liaising with Myenergy....I may call them myself. From VW's perspective I am still waiting for a response
 

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Have you called myenergi tech support and been told its the car?
My e-Golf chargers ok in fast mode and with the boost timer. Most F the time its fine in eco+ as well, but now it's autumn I'm only using fast mode overnight.
There are a few issues I've read about with the e-Golf but not with a pilot problem that I remember.

Myenergi are saying that the car manufacturers aren't sticking rigidly to the protocol and it is causing them all sorts of issues.

In the Zappi V1 firmware the VW cars were OK. They did have to make some changes but they got it sorted. When myenergi upgraded their firmware to version 2 there were many issues introduced. The e-Golf is one of the last cars they are working on and I'm expecting they will get it running smoothly at some point.

Is your local VW garage being helpful? Mine were very good when we had issues early on and checked for updates, checked with VW UK etc. It might be worth pressing them for any updates. We have had surprising things occur that needed a software update, the sos system flashing up and speaking error messages repeatedly while driving along was the one I remember clearly.
And thank you for your response!
 

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We have a Kona, not a Smart: does sound like a car issue. Hopefully they will sort it out.

Must admit we have always just left ours in the Eco mode - ie, topping up from grid when it falls below a certain level (think ours looks like 1.2kW, not 1.4).
Particularly when I saw Eco+ dropping when a cloud goes over....the flipping on-off-on cannot be good for the poor unit😂
 
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