Minor CCU connection problem

OriginalBigAl

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For the last few weeks when scheduled charging either to 70/80/100 % the charge has been stopping 3% short and terminating. It seems like the balancing portion is being missed , I have to assume its a connection problem (software) where the car is not telling the EVSE to ramp down. If I manually then select "charge now" it does finish off the expected charge at balancing levels, but not automatically.
Has anyone else noticed this, is it a pre-cursor to the CCU problems others have had? Its not such a big problem and the car is booked in for the second service in a months time, so I'll log it and mention it then and see if any software updates fix it. I will not bother doing the 10 mm spanner trick ( for now) . As usual, any thoughts welcomed.
 
When my CCU failed it failed within a couple of charges and it would only put a few watts into the battery when I tried the "charge now" option before stopping.

Can you try someone else's AC charger just to rule out that it's not your charger causing the problem?
 
Update: to post #1. My normal routine charge is from around 30% to 70% inputting around 24 kWh . These figures of course vary slightly and up until recently everything was fine with the charge finishing with a balance then stopping. The EVSE would then report final kWh , time taken, and temperature. The temperature is strange because it not clear whether it's the battery temp or the EVSE temp? Last night I gave it a full balance charge from 13% to 100% . On inspection this morning the charge had stopped at 53% . The EVSE reported 0 % because it was just cut off .
On unlocking the car it then resumed the charge before re-locking itself. Now in daytime and able to monitor it , it was fine until it reached 96% when it shut down again.
Again the simple act of unlocking it, and self re-locking resumed the charge and its now gone on to complete to 100% and balance. The current reported temperature is 58°C.
It appears that once it's input 24-25 kWh ( 40% ) it prematurely shuts down??? In the case of the monitored portion I could hear the cooling system pumping fluid around , so that appears to be working. The overnight temperatures were cool ( 16°C ), the car being used the previous day up until 4 in the afternoon, the charge being set for midnight.
My normal charge and description as in post #1 could now just be coincidental that the car has shut down the charge at the 24 kWh level .
Apart from temperature or a BMS/ CCU anomaly I'm running out of ideas.
I will report to the service department in a couple of weeks time but they will most likely say " No , it doesn't do that." before even looking at it.
I did try a granny charger as suggested but not for a longer ( more than 24kWh ) charge.
 
Could be an emerging CCU failure.... they get progressively less able to charge over a few weeks typically before it refuses to charge at all. Mine initially showed up exactly like this: just started to stop a few percent short of full.

Early on with this kind of fault you need to do a long charge to test this properly, it should never terminate before 100% normally, the cooling system can easily cope with AC charging and on Rapid chargers will simply reduce charge rates to very low rates (I have seen as little as 2kW!) if it gets very full or hot.

Basically it should never stop early unless there's some kind of fault, schedule or other limit set (except on rapid chargers where it is normal for it to stop between 95-97%).

Best comparison is to use another AC charger and make sure you do a charge delta of at least 50% to see if it is your equipment vs the charging system.
 
I have also contacted Morec the EVSE manufacturer to see at what temperature their equipment cuts off the charge, as the reported figure on the screen is always higher than you would imagine. As of yet no reply!
 
The EVSE would then report final kWh , time taken, and temperature. The temperature is strange because it not clear whether it's the battery temp or the EVSE temp?
I'd say it has to be EVSE temperature, because I don't believe that there is any way that an EVSE can obtain the battery temperature via the Type 2 port.

Though when doing a rapid charge, that sort of data would be available via CAN bus communications, and that happens via the Control Pilot pin, and that is available. But the control pilot is "busy" sending a 1kHz pilot signal that tells the car the maximum charge current to draw. I doubt that they would do the CAN bus communications at the same time, even though it could technically be possible.
 
I'd say it has to be EVSE temperature, because I don't believe that there is any way that an EVSE can obtain the battery temperature via the Type 2 port.

Though when doing a rapid charge, that sort of data would be available via CAN bus communications, and that happens via the Control Pilot pin, and that is available. But the control pilot is "busy" sending a 1kHz pilot signal that tells the car the maximum charge current to draw. I doubt that they would do the CAN bus communications at the same time, even though it could technically be possible.
Agreed I am leaning towards the EVSE temperature sensor reading the wrong temperature both when originally connecting ( but not charging ) and increasing in value whilst waiting. I think it may use the casing as a sort of heat sink and any heat paste may have degraded? As an experiment I let the temperature rise to 54°C then placed a wet rag over the top of the casing , It took about 10 mins but reduced down to original 46°C when connected . The outside air temp was 38°C and the unit is in constant shade. If the sensor is around 8°C out then it would cut off the charge earlier as it passes its pre-set value sooner than really necessary. I am going to see if it charges better by putting a wet towel which has been in the freezer for a couple of hours over the top before charging begins.
 
I am going to see if it charges better by putting a wet towel which has been in the freezer for a couple of hours over the top before charging begins.
That should rule in or out the EVSE temperature sensor as the source of the problem.

Assuming it is the problem, consider putting a resistor in series with the sensor to reduce the reading error at room temperature (assuming that it's a common Negative Temperature Coefficient or NTC type). Higher temperatures means lower resistance for those.

Or possibly improving ventilation somehow, but that sounds fraught (possibly allowing insects in for example).

I doubt that the EVSE manufacturer would be interested in fixing it, although it sure sounds like a design fault affecting usability, and arguably its fitness for purpose.
 
That should rule in or out the EVSE temperature sensor as the source of the problem.

Assuming it is the problem, consider putting a resistor in series with the sensor to reduce the reading error at room temperature (assuming that it's a common Negative Temperature Coefficient or NTC type). Higher temperatures means lower resistance for those.

Or possibly improving ventilation somehow, but that sounds fraught (possibly allowing insects in for example).

I doubt that the EVSE manufacturer would be interested in fixing it, although it sure sounds like a design fault affecting usability, and arguably its fitness for purpose.
I have been in contact with the Customer Service Dept, Morec ( China ) and they are very helpful , pleasant and seem to want to understand my concerns.
Two of the major problems are that presently we are in a heatwave and temps vary between 42 and 22°C which is not helping, and that when in standby mode the EVSE warms up to around 10 degrees above ambient. Whether or not this is an anomaly , I don't know.
The good news is that putting a 52 % charge in with the granny charger in high temperatures worked fine , so I can ( but not entirely ) say that the car is charging as normal and hopefully discount that as a problem, which TBH was my major concern.
 
Further update with different behaviour. Our present guests arrived with a MG4 with the same battery and 11 kW onboard charger. Last night they used the EVSE to put in around 40 kWh, 67% . With the outside temp around 34°C.
I happened to be around , when after charging at 10kW for 35 mins there was a simultaneous click from both the box and the car and it shut down, temp 58°C. Without intervening after 20 secs the charge automatically resumed , again 10kW.
The EVSE records the time spent charging and I think this process repeated (8 kWh in, shutdown, restart ) until the 100% level was reached. After 4 hours the recorded temp was 65°C but by this time I had put a wet towel on top of the box to try to dissipate the built up warmth.
We are expecting some cooler weather soon and I will retry mine and will monitor it more thoroughly.
 
On the side panel : -25°C to + 55°C. Never seen temps (actual ) at the lower end , we now for around 10 days a year surpass 40°C but try never to charge up on those days. The recent hot spell , +36°C for the last two weeks plus, and down to 25°C at night does not leave much margin before the thyristor calls it a day. But it has surpassed 60°C on many occasions without tripping?
 
I was going to do a long charge and in a moment of inspiration , thought, I'll turn the charge rate down to give the EVSE an easier time. Going into the charging screen to select an option I find I've been diddled, normally I am on Max ( 10.2 kW - 3.4 kW per phase or 14amps. ) . the next selection down is 16amp ? more than I get on Max so will default to the same. Down one step further and 8 amp , around half of what I get on Max , then down again to 6amp?
I can see the logic if your max value is 32 amps for single phase , if indeed that's what Max means for 7kW charging, then halving and halving again. But for 11kW charging we only get one real other option . And in all cases what's the point of 6amp selection , has anyone ever used it ? its only 2 amps down on the one above . A 10 amp choice would have made more sense as an alternative , still , mustn't grumble. :confused:

[ Moderator: kwh -> kW for charging rate ]
 
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Can you not adjust the charge rate in your EVSE? (I know I can with my Wallbox Pulsar Plus ... from 32A to 6A in 1A steps).
 
But for 11kW charging we only get one real other option .
Yes, they should have different limits for models with 3-phase on-board chargers.

Though the limits still make sense for single phase EVSEs. The 11kW on-board chargers can parallel two of the internal 3.6kW units to effectively become a 7.2kW (at the charger plug) on-board charger.

This is also a limitation of the way that the single-phase J1772 standard was "translated" to 3-phase Type 2: the 6A minimum becomes 5.76 kW minimum. Not great for trying to match EV charging power to available solar power on a cloudy day. But I guess the alternative (using total phase current) would be worse, and the convention is always that 3-phase current is the current in each phase, not the total current. And besides, when AC currents are added, they do so vectorially, so the total current to a balanced load is zero.

And now, back to the topic 😳
 
I'm puzzled why the EVSE is getting that hot. You mention 'thyristor' (in post 12), but AFAIAA EVSE's normally use contactors rather than thyristors or triacs for switching the AC. In which case the only significant heat (apart from a little microcontroller) would be from poor design by not having sufficient gauge wires within it or a poor contact creating more resistance than expected ?
 
I am in contact with Morec because I am puzzled as well. I have seen strip down videos on Youtube ( not my model ) and that was using a relay to switch the current with a thyristor stuck to the side to act as a temperature cut off wired into the circuit board. As mine is 3 phase I do not know if it has 3 or 4 relays ( including neutral ) or more likely a contactor with again a thyristor to control cutting off the current should it get too hot.
If the system is completely off , then the Evse is at air temperature. Powering up to 1st stage standby the switch is lit along with a central light but with only a slight temperature gain.
Pressing the switch lights up the screen, 2nd stage standby. The screen and surround warms up a little bit more.
Plugging in the car ( scheduled to start in 4hours ) the screen changes to "waiting for car" with Info for time, voltages, power ( kw ) and internal temperature, which then starts to rise ( 0,1 c every 20 secs until its around 10c above air temp. Screen becomes warmer to the touch.
When car is charging , temperature then rises again at about twice the rate previously, and the front panel is a lot warmer than you would think it should be. ( temp getting up to 60c )
This as become more noticeable over the last few weeks with the charge cutting off after about 24 kw ( 2.50 hours unseen ). coinciding with the hot weather, but it as been this hot previously and this is new behaviour.
The main concern is that its not the CCU in the car , with what's gone on with other members so I am want to try to isolate the fault to the Evse for peace of mind , but to do that I have to try all the different permutations of charging up. As of present its having slightly different behaviour on two identical cars . Our guests are charging up to 100 % this evening ( hopefully ) and I'll be putting in 60% tomorrow, when I can monitor its progress. The present air temps are 20c down on the last couple of weeks.
Putting a damp towel on top of the casing did appear to help as a heat sink.
 

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