I had the latest (Feb 21) BMS installed in my car a few weeks ago and tried timed charging. Initially, my BP Chargemaster/Pulse unit wouldn’t charge at all after this change, not even as a dumb charger. I took it back and the dealer who then updated my ECU’s to ensure they were compatible with timed charging. I’ve no idea what he actually did on that occasion but thanks to this forum, I’ve learned that many dealers do not understand that there may be a need to update other ECU’s when updating the BMS, and mine wouldn’t have done so without my prompting. I tried timed charging again after getting the car back, but it still wouldn’t work. The BP Unit was responsive again, but just started charging at full speed immediately the cable was connected. I’ll explain at the end why I suspect that was the case. Then I set up a new test schedule for the slowest rate of charging from 1am to 3am daily on the Chargevision Website approximately 5 days ago. It wasn’t intentional to set the schedule that far in advance of my next charge, that’s just the way it worked out. When I plugged the car in at 8.30 last night, I could hear the noise of the charge cable locking and whilst the yellow light on the BP Homecharge unit remained on, the green light did not come on and the car did not start charging straight away.
I checked the charge status of the car and unit around 10.30pm and again just before 1am. Everything appeared to remain the same. 1am came and the unit did not switch on, but I know the unit does not communicate with the server constantly and I kind of expected this. I hung around in my garage and at 1.06am SUCCESS! The green light came on, the car awoke and the car dash showed that it was now charging! I had to be up that night anyway for my son, so I kept an eye on charging progress on the Smartcharge phone app. Interestingly, 30 minutes into charging, the app showed the car had been charging for 1hr and 30 minutes, but the level of charge was consistent with the 30 minutes the unit had actually been charging for. I don’t know why this is, but it’s nothing to worry about. The car continued to charge and switched itself off at 3.01am having delivered 3.46kwh at a rate of 1.73kw/h. Using the slow charge was deliberate, firstly to see if the unit would obey this command, and secondly to make sure the battery wasn’t full and so I could see if/how the schedule override worked in the morning. At 8.50am this morning, I pressed the “Charge At Full Speed” button on the app, but whilst the app told me that the car was charging, it was not. I tried the same override on the Chargevision website with the same negative result. I then opened and closed the door (still unlocked) and this seemed to wake the car and it started charging at full speed which is where I am now. I need to go out this afternoon and will tell the charger to revert to the saved schedule once it has delivered enough charge for my needs for today. I will report back tomorrow about whether or not it works again tonight. You should know that generally, there may be a problem getting timed charging to work if you connect the car more than 8-10 hours in advance of the scheduled charging start time as it may go to sleep and be unresponsive to the Homecharge unit commands. You may also need your BMS and ECU’s updated if you have not already done so. I can’t advise on that, but your MG dealer should be able to. Get him to contact MG if he doesn’t know.
In respect of the first failed timed charge after the ECU update mentioned above, I cannot be sure, but I think it is important to allow the charger sufficient time to communicate with the Smartcharge app or Chargevision website before plugging in the car. It shouldn’t need as long as 5 days, but it probably needs more than an hour on the first setting up of a new schedule. I was inspired to persevere and experiment thanks to the posts of GrahamH earlier in this thread, so thank you to him. I am now engaging with MG to let them know the results of my experiments to try and find out what does and doesn’t work. I hope all of this helps!
