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Home charging speed problems - EO Mini Pro

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I'm struggling with similar issues on an EvBox Elvi charger. It's been working fine for the past month or so, delivering 32A solid on overnight charging. Last week it started reducing the advertised current. So the charge starts fine at 32A but a half hour later or so, it drops back to between 24A and 26A and stays in that region, wobbling about a bit, but never going back to 32A.

I can see that it's the charger not the car since the second number is lower on the mobile app - e.g. 24/24. Last night, it dropped even further to 12A.

I'm assuming it's a charger problem rather than some DNO imposed limit. How would the DNO go about that anyhow?
 
Hi Jeremy, couple of questions:
- I thought powering on the charger in the middle of the night if the Tesla is asleep results in no charge being taken because the car doesn't wake up. Is this not your experience?

TBH, I've not charged the Tesla overnight yet, and wasn't aware that it had a problem with timed charging. It used to work fine with my i3. I'll plug the car in on a timed charge tonight and see if if it works or not. It should do, as the protocol requires vehicles to respond in a predictable way to changes in the control pilot signal, and so if the car sees a State B it should just sit and wait for the charge point to go to State C (charge power available).

Effing car doesn't follow the charging protocol, does it? Bloody Tesla, why do they have to make up their own sodding rules and ignore the way standards have been written?

Car didn't charge last night, despite the charge point having turned on at 12:05 and off again at 06:55, for an E7 rate charge. I've double checked, and the charge point is doing exactly as the spec says it should, it seems that the bloody car is not compliant (why am I not at all surprised?).

So, this means that some functionality of smart charge points may a waste of time, as if the car refuses to respond properly to a charge point that turns on some time after being plugged into the car then that means owners are going to find that their cars haven't charged when they expected them to.

I guess the work around is to use the in-car charge settings, but from what's been reported here they are as flaky as hell. All I want to do is what I've been doing for the past 6 years, plug the car in when I get home and only have it charge during the off-peak period, without having to faff around playing with the car settings, or getting up in the middle of the night to plug the damned thing in. It should just do this, just as the other EVs/PHEVs I've owned did - they all used exactly the same protocol, and followed it, whereas Tesla, probably uniquely, seems to have implemented a time-out on monitoring the charge connector.
 
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Cold weather can affect it... Also how charged is the battery?
Cold battery does affect charge rate but that is on DC fast charger delivering 50kw+. home charger is 7kw ( unless you have 3 phase) which is a tiny fraction of what the car can handle. Someone correct me if I am wrong but I can't imagine it ever gets cold enough in the UK for the car not to be able to handle a 7kw charge rate.
 
A bit of an update from me.

I logged out of the EV app and deleted it from my phone.

Got home and plugged in, I could increase the limit to 32a! :)

Set the schedule in car to start at 12.30 when electricity is 5p/kw. Car charged for 3 hours 5 mins and used 24.7kw (£1.23)

I'm hoping that's it now sorted. Will try again tonight and see what happens.

Thanks again for all the help
 
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Further to the above, it seems that the car is not working as described in the manual (may be the manual isn't current?). The manual states this (my bold):

If the charge port light turns red while charging, a fault is detected. Check the touchscreen for a message describing the fault. A fault can occur due to something as common as a power outage. If a power outage occurs, charging resumes automatically when power is restored.

This is precisely the behaviour of any charge point that has built-in charge timing (if it follows the SAE J1772 / IEC 62196 standards/protocol). In effect, the charge point is "off", as far as the car is concerned when it's either had it's power cut by an outage, or if the charge point is timed to be off (0V VDC or -12 VDC being put on the Control Pilot by the charge point, -12 VDC should be ignored due to the integral diode inside the vehicle connection).

Last night my car was set to "charge immediately", and plugged in to my charge point, which was effectively off (the time switch had set it to be off). The time switch activated at 12:05, and the charge point turned on, and it seems that the car then loaded the Control Pilot correctly to State B (the +9 V vehicle connected state) and the charge point started advertising the available current OK (the Control Pilot PWM started up). The car did not then load the Control Pilot to State C and initiate a charge.

I need to do some more work on this, as I'd much rather control whether to charge the car immediately, or whether to only charge it during the off-peak time, by simply flicking the switch on the charge point. Having to unlock and get into the car and faff around changing settings on the screen will be a major PITA.
 
I need to do some more work on this, as I'd much rather control whether to charge the car immediately, or whether to only charge it during the off-peak time, by simply flicking the switch on the charge point. Having to unlock and get into the car and faff around changing settings on the screen will be a major PITA.
Any of the Tesla remote apps should let you fiddle with the settings from the comfort of your armchair. TeslaFi is browser (not app) based, but costs $50 a year.
 
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One thing I could try is to rewire the selector switch and time switch to simulate a power outage. Not hard to do, and it would prove whether or not the car is actually doing what the manual says it should.

In essence, by removing power to the EVSE controller, I'd be simulating a power outage, as the contactor would be open and there would be nothing on the Control Pilot, it would be floating, in effect, but partly pulled down to 0V by the load in the car. This isn't really a specified state in the protocol, the closest might be State E, the error state, where the CP is loaded to 0V (same as a CP short, but in this case only a positive going short, because of the internal diode).

In theory the car should just ignore this state, as the car isn't supposed to do anything active on the CP at all, all it's supposed to do is load it with varying resistances and measure the duty cycle, if the pilot frequency is up and running. Nothing would surprise me with Tesla, though, as I suspect they have their own unique way of handling things.

Not hard to do the rewiring so the switch/time switch cuts power to the EVSE controller. Not ideal, but it might prove a point. The one thing it would demonstrate is whether or not the car has the capability to remain in the "ready for charge power" state (State C) during a simulated power outage for long periods of time (several hours) and then be able to detect power coming back and starting to charge. Might need some fiddling about to simulate this, like having the charge point turned on initially, whilst plugging the car in, then flicking the switch to cut the power, and have the time switch turn the power back on again.
 
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One thing I could try is to rewire the selector switch and time switch to simulate a power outage. Not hard to do, and it would prove whether or not the car is actually doing what the manual says it should.

In essence, by removing power to the EVSE controller, I'd be simulating a power outage, as the contactor would be open and there would be nothing on the Control Pilot, it would be floating, in effect, but partly pulled down to 0V by the load in the ca. This isn't really a specified state in the protocol, the closest might be State E, the error state, where the CP is loaded to 0V (same as a CP short, but in this case only a positive going short, because of the internal diode).

In theory the car should just ignore this state, as the car isn't supposed to do anything active on the CP at all, all it's supposed to do is load it with varying resistances and measure the duty cycle, if the pilot frequency is up and running. Nothing would surprise me with Tesla, though, as I suspect they have their own unique way of handling things.

Not hard to do the rewiring so the switch/time switch cuts power to the EVSE controller. Not ideal, but it might prove a point. The one thing it would demonstrate is whether or not the car has the capability to remain in the "ready for charge power" state (State C) during a simulated power outage for long periods of time (several hours) and then be able to detect power coming back and starting to charge. Might need some fiddling about to simulate this, like having the charge point turned on initially, whilst plugging the car in, then flicking the switch to cut the power, and have the time switch turn the power back on again.
I look forward to what you discover!