Charging 10%-100% every 3-6 months

[fnegroni]

It also helps to ensure the starting level is stable, which means leaving the battery at the lowest state of charge for an hour or two before starting to charge.

 

[MickeySw]

It also helps to ensure the starting level is stable, which means leaving the battery at the lowest state of charge for an hour or two before starting to charge.

Correct, measuring a SoC based on cell voltage is best done when the cells have been idle for a period, the longer that period, the more accurate.

I have never observed a complete AC slow charging session of our MG but I assume it’s similar to other manufacturers, i.e. the car automatically stops charging at certain voltage levels to measure SoC under ‘no load’ (more like minimum load) conditions.

I’m therefore not sure if turning off the car idle for a prolonged period of time ahead of a calibration charge is going to make much of a difference?

 

[fnegroni]

Correct, measuring a SoC based on cell voltage is best done when the cells have been idle for a period, the longer that period, the more accurate.

I have never observed a complete AC slow charging session of our MG but I assume it’s similar to other manufacturers, i.e. the car automatically stops charging at certain voltage levels to measure SoC under ‘no load’ (more like minimum load) conditions.

I’m therefore not sure if turning off the car idle for a prolonged period of time ahead of a calibration charge is going to make much of a difference?

Using a ‘granny’ and a Tapo smart plug, I’ve never seen the charger drawing less power or idling for any period of time during a charging session no matter what the starting voltage was, except for the final balancing at 100%.
I don’t know how much difference it makes to let the voltage settle at low SoC but as we seem to agree it can only be beneficial if it can be done

 

[tsedge]

I appreciate that these are efforts to find the perfect conditions for this 10-100 charge. However, I really don't think it matters much, at least on NMC. I have never done it and no issues at all after 13,000 miles and 14 months.

 

[MickeySw]

I appreciate that these are efforts to find the perfect conditions for this 10-100 charge. However, I really don't think it matters much, at least on NMC. I have never done it and no issues at all after 13,000 miles and 14 months.

Good to hear, that means that in your case the BMS seems to be able to accurately calculate SoH without the need for an actual calibration charge as your ‘usage’ fits the battery degradation model.

Even if the value is out by a couple of Ah you won’t really notice unless you try and squeeze every bit out of the battery.

 

[Rolfe]

That's why I wanted to do mine this week. Setting off in an SE SR for a long road trip tomorrow. I don't want any nasty surprises.

 

[Martinonline]

Is the discussion about more accurately assessing the SOC or SOH? Both have been mentioned or is one a typo?

 

[Rolfe]

SoC, I think.

 

[MickeySw]

SoC, I think.

Actually both, if you count how much ‘fits’ into a battery you can calculate two values:

• SoH if you compare it with the initial figure when brand new
• SoC if you compare it with the current max capacity

 

[Rolfe]

Oh, I see.

 

[aardvark5]

Thread necro

If you don't balance charge can you bugger the battery up?
Or is it for owners who want to see a more accurate figure?

 

[Matt x power]

Yes, it's to keep the battery healthy and holding charge correctly

 

[aardvark5]

Yes, it's to keep the battery healthy and holding charge correctly

Thanks

Has any MG4 Trophy LR owner worked out how long it takes to charge 10% so I can workout how long it could take?

 

[MickeySw]

Thread necro

If you don't balance charge can you bugger the battery up?
Or is it for owners who want to see a more accurate figure?

Balancing cells and a battery capacity calibration (<10 to 100%) are two different procedures.

The latter is to insure that the calculated SoH is in line with the actual pack capacity.

Usually the calculation is more conservative, i.e. car’s range could actually be slightly higher than indicated.

 

[HazardLights]

Assuage: to make unpleasant feelings less strong.

To save others looking it up ?

Assuage is the opposite of Assange

Thanks

Has any MG4 Trophy LR owner worked out how long it takes to charge 10% so I can workout how long it could take?

Roughly an hour for 10% on a 7kW charger. Roughly 3% an hour for granny chargers.

It's odd that the option to limit the charge isn't on her phone, a bit like it's not on the MG app for the SE SR. It makes me wonder if her phone has an LFP battery, but I have no idea how to find out.

This is a feature that was released in Android 15 maybe she has an earlier version.

 

[siteguru]

Some other makes added this feature in earlier Android versions too (so I believe). I know @Rolfe's phone offers that feature - not sure what Android version hers is running but I thought it was Android 14.

 

[HazardLights]

Some other makes added this feature in earlier Android versions too (so I believe). I know @Rolfe's phone offers that feature - not sure what Android version hers is running but I thought it was Android 14.

I think Samsung had it before Google introduced it on Pixel phones.

 

[siteguru]

I think Samsung had it before Google introduced it on Pixel phones.

That would explain it, as I think hers is a Samsung.

 

[Roraider]

Learn something new everyday, didn’t know about the 3 to 4 month drop to 10%. Thanks.

 

[Coulomb]

It makes me wonder if her phone has an LFP battery, but I have no idea how to find out

I don't believe that any phone has an LFP "battery" (generally, they're only one cell, so technically not a battery). The LFP cells are too low in voltage, and energy density is very important for most phones.

I suppose it's possible that some low end phones could come with two LFP cells in series, but then you need the extra electronics of a battery management system. But it would really then contain a battery.