Battery charging and balancing

Tom Hartley

Established Member
Joined
Jan 23, 2021
Messages
96
Reaction score
42
Points
32
Location
Grimsby
Our MGZSEV has covered 4700 miles and we have an Ohme home wall charger. Today the Ohme indicated that the charge was complete and the cars MGs front grill symbol was no longer illuminated. I pressed the drivers door handle without the car key in my possession and then noticed the charger had restarted, the MG symbol was illuminated and constant as when the battery is balancing. I wondered if anyone else had experienced this and why after the charge had seemingly finished pressing the door handle without the key may have caused the rebalancing?
 
Yes I have witnessed this, it does not carry on the renewed balancing for very long though.
 
Our MGZSEV has covered 4700 miles and we have an Ohme home wall charger. Today the Ohme indicated that the charge was complete and the cars MGs front grill symbol was no longer illuminated. I pressed the drivers door handle without the car key in my possession and then noticed the charger had restarted, the MG symbol was illuminated and constant as when the battery is balancing. I wondered if anyone else had experienced this and why after the charge had seemingly finished pressing the door handle without the key may have caused the rebalancing?
If the key was out of range of the car and you pressed the button on the drivers door, and it attempted to start charging again ( which is completely normal ) this may suggest that your car has been set up to allow charging to take place from a A/C supply, with the car unlocked !.
Which is a good feature to have for some owners.
My car only allowed this after it had the latest BMS update.
Prior to this, it would not charge with the drivers door open on a A/C supply.
This can be handy if you are cleaning the inside of the car while wanting to charge at the same time?.
 
You could always sit in the car and charge (prior to the update), just lock the doors, there is no internal alarm sensor. Safer to sit in a locked car anyway.
 
When I topped mine up to balance it yesterday, according to my smart meter monitor it went from charging to finished with no apparent tailing off of the current draw, as it would normally do when balancing. I checked the car and the MG badge was not illuminated. I wasn't convinced that it had balanced so I opened the boot to check the dash display and it said "Finished" etc. which it does when it's still balancing. As I did this I heard the plug lock activating and when I looked at the badge it was now illuminated solid again, indicating that it was balancing and according to my smart meter monitor, drawing around 300W, it took around another 30 minutes to finish.
Did the car decide that balancing wasn't required initially and go straight from charging to off (the cells were 40mV out the last time I charged it) ?
FWIW when this charged finished the cells were only 32mV out
Has anybody else experienced the charge finishing without going on to balance ?
 
Has anybody else experienced the charge finishing without going on to balance ?
Can’t say that I have, but I let it do it’s thing, generally over night.
I can set my start and finish delayed charge times from my phone.
If I am going to carry out a balance, then I commence the charge to start in the early hours, then I avoid setting a finish time.
This way, the car will dictate when the cycle is complete and switch the wall box into standby mode.
Incorrectly setting an early finish time, could prevent the car from fully balancing.
Even if the car is fully charged and balanced, it will still attempt to commence another session, if I plug the car back in.
Not sure how long it would take for the car to realise it was already fully balanced ?.
 
I had left the car maybe half an hour after the monitor showed it had finished, sometimes in the past I've left it a couple of hours. I think I might open the hatch again every time it appears to have finished balancing from now on, or unplug and plug it back in again. It might bring my battery more in balance, it seems to have been consistently around 40mV out from max to min cell voltages previously, this last restart of the balancing seems to have brought it down to 32mV.
 
I had left the car maybe half an hour after the monitor showed it had finished, sometimes in the past I've left it a couple of hours. I think I might open the hatch again every time it appears to have finished balancing from now on, or unplug and plug it back in again. It might bring my battery more in balance, it seems to have been consistently around 40mV out from max to min cell voltages previously, this last restart of the balancing seems to have brought it down to 32mV.
Will it not display the dash panel, if you press the button on the drivers door IF you keep the keys out of range ?.
Rather than popping the hatch back ?.
The car will still need to be connected to the wall box though.
 
I had left the car maybe half an hour after the monitor showed it had finished, sometimes in the past I've left it a couple of hours. I think I might open the hatch again every time it appears to have finished balancing from now on, or unplug and plug it back in again. It might bring my battery more in balance, it seems to have been consistently around 40mV out from max to min cell voltages previously, this last restart of the balancing seems to have brought it down to 32mV.
May be worth trying it, to see if it can get that low cell of yours back up with the others.
 
Will it not display the dash panel, if you press the button on the drivers door IF you keep the keys out of range ?.
Rather than popping the hatch back ?.
The car will still need to be connected to the wall box though.
Yes, but it was quicker to pop the hatch because I already had the keys in my pocket.
 
May be worth trying it, to see if it can get that low cell of yours back up with the others.
That's what I thought, it's already come up from 4.178V to 4.191V on this balance.
I was wondering if this was the reason that it hadn't come up much over the last balances, maybe it didn't go on for long enough.
 
That's what I thought, it's already come up from 4.178V to 4.191V on this balance.
I was wondering if this was the reason that it hadn't come up much over the last balances, maybe it didn't go on for long enough.
I do wonder if it's related to the balancing issues that they were trying to fix in the old/original bms - you are still running it aren't you? maybe getting the new bms will sort it out
 
Our MGZSEV has covered 4700 miles and we have an Ohme home wall charger. Today the Ohme indicated that the charge was complete and the cars MGs front grill symbol was no longer illuminated. I pressed the drivers door handle without the car key in my possession and then noticed the charger had restarted, the MG symbol was illuminated and constant as when the battery is balancing. I wondered if anyone else had experienced this and why after the charge had seemingly finished pressing the door handle without the key may have caused the rebalancing?
How are you getting along with the Ohme? I have read mixed reports / reviews of the Ohme App. Ours is being fitted tomorrow. Any hints or tips appreciated - Except, 'Don't get it' Too late for that... :)
 
I do wonder if it's related to the balancing issues that they were trying to fix in the old/original bms - you are still running it aren't you? maybe getting the new bms will sort it out
Could be, but I wouldn't want to introduce other anomalies into the mix, better the devil you know and all that. ;)
 
How are you getting along with the Ohme? I have read mixed reports / reviews of the Ohme App. Ours is being fitted tomorrow. Any hints or tips appreciated - Except, 'Don't get it' Too late for that... :)
 
How are you getting along with the Ohme? I have read mixed reports / reviews of the Ohme App. Ours is being fitted tomorrow. Any hints or tips appreciated - Except, 'Don't get it' Too late for that... :)
I've had my ohme charger for 2 weeks and I'm sorry to say i wish id gone elsewhere, mg does not provide them with the API so the intelligent part does not work, i.e. it does not show how much charge is left in your battery, it thinks it at 0%
 
Our MGZSEV has covered 4700 miles and we have an Ohme home wall charger. Today the Ohme indicated that the charge was complete and the cars MGs front grill symbol was no longer illuminated. I pressed the drivers door handle without the car key in my possession and then noticed the charger had restarted, the MG symbol was illuminated and constant as when the battery is balancing. I wondered if anyone else had experienced this and why after the charge had seemingly finished pressing the door handle without the key may have caused the rebalancing?
Further to my original question, overnight the same occurred i.e. the car indicated it had finished charging from the wall charger after I pressed the drivers door handle without the keys nearby. Then the MG front grill pulsated and went steady to indicate balancing in progress. I still wonder why.
Kithmo mentioned about balancing etc: " it's already come up from 4.178V to 4.191V on this balance"
How do you get this type of information please?
Regarding Laurence Bs previous question about the Ohme, we do not use its smart features so as a "dumb" charger it does its job and was competively priced.
 
I've had my ohme charger for 2 weeks and I'm sorry to say i wish id gone elsewhere, mg does not provide them with the API so the intelligent part does not work, i.e. it does not show how much charge is left in your battery, it thinks it at 0%
That's nothing to do with the Ohme charger though, none of them get this info from the car.
My issue with the Ohme is that it's only geared up for cars that provide all that data, with the MG we just need a simple schedule facility to be provided by the Ohme charger/app, I've had to setup a bodge configuration to get it to charge as I want it to using my off-peak rate etc.
 
Support us by becoming a Premium Member

Latest MG EVs video

MG ZS EV Retrospective & First Look at the MGS5 EV | Live Q&A with Owners & MGEVs Panel
Subscribe to our YouTube channel
Back
Top Bottom