MG4 Equalisation Charge

[Lovemyev]

Thanks folks,
This seems to start making sense now. I am having a Zappi fitted on Monday and will try out the 80% and 100% charging tests very soon and report back (if nobody's beaten me to it!).

Which model do you have ?.

 

[EV convert]

Not sure which you mean but my car is an MG4 Trophy and the charge point will be a Zappi 2.1.

 

[Tigger]

I am having a Zappi fitted on Monday and will try out the 80% and 100% charging tests very soon and report back (if nobody's beaten me to it!).

Good luck! However, you might want to look at the parallel thread, Cell balancing on LR with Zappi

On this thread, Big Al says:
However what I’m seeing on my Zappi is that when the charge reaches 100%, no further current is supplied for the cell balancing. It just drops from 7kw to 0. And the Zappi displays “charge complete”

Does this mean that the Zappi (somehow) doesn't do cell balancing? Who knows? Maybe you can clarify this.

I thought of doing this test a few days ago myself, but didn't want to charge to 100% until I have a long trip lined up. When I do, I can contribute further to this discussion (my Pod Point definitely does equalisation).

 

[Tigger]

I have just done this test, starting charging my Trophy at 78%. It charged at 6.2kw for 14 minutes before it reached 80%, which is what I would expect. Then it carried on charging at 6.2kw for another 4 minutes, dropping to 4.6kw for 2 minutes. Next it entered a variable state, charging between 0.06 & 3.93kw and back again repeatedly, for another 4 minutes. Finally it stabilised at 0.04kw or thereabouts for 6 further minutes, before terminating.

This looks to me like equalising behaviour. The gross power leaving the Pod Point charger was 3.2kwh. If we assume 92% efficiency, this equates to 2.94kwh actually reaching the battery. I estimate that increasing the charge level from 78%-80% took 1.3kwh or so, leaving 1.6kwh unaccounted for. If this wasn't used for balancing, what was it used for?

I repeated this test last night after driving only 64 miles, with no intermediate charges. This time
it charged at 6.2kw for 8 minutes going from 78% to 80%. Then it carried on charging at 6.2kw for less than 1 minute, dropping to 3.3-4.6kw for 4 minutes, then dropping to zero.

The gross power leaving the Pod Point charger was 2.2kwh, I.0kwh less than last time. This behaviour is consistent with the car doing a partial equalisation last time, meaning it didn't have to do as much this time. So whatever the official story is, the evidence seems to support the theory that some equalisation does take place when the charger reaches the target battery level (of 80% here but why not other percentages as well?).

 

[wandle MG4 trophy]

I balanced charged my Trophy for the first time yesterday. It’s 2 months old and has done 1100 miles and has only been on a fast charger once. The car did not say I needed to balance charge but I thought I would do it anyway as I had a long journey planned.
I use an Easee One home charger which intelligently spreads the charge equally over my four hour cheap rate window. This means it would not charge quickly to 100% in say the first couple of hours and then drop back to allow balancing for the remainder of the period.
The solution for me was to disable scheduled charge on the Easee app and instead select Delayed Start. This setting allowed the car to charge relatively quickly and still allow time for balancing during my off peak window.
Once the car reached 100% it drew another .5kwh total over about 45 minutes whilst balancing.
After balancing I did not see any range increase in the GOM

Moral of the story - if you have an intelligent charger you may need to disable scheduled charge before doing a balance charge.

 

[Les burrows]

Once again yet another thread about balancing the batteries in EV and in this case MG evs
The most important thing to remember is and as been point out many times here and before is, you have no control over when are for how long the balancing takes place all you can do is to make sure you use an AC charger of any type and fully charge the car it will decide if and for how long it needs to do a balance for if it needs to.
Most handbooks recommend around once per month but every couple of weeks will do no harm but it must be on AC currant not DC.
EVs can not balance on DC rapid charging points
Les

 

[stevegus]

EVs can not balance on DC rapid charging points
Les

Highly likely because DC charging uses the controller in the charger and not the inbuilt charger in the car.

It wont have access to monitor the batteries like the internal ac charger has. The comms between the car and charger is quite limited.

 

[colsky]

Apologies if this has been asked before, but does the MG4 do a balance, no matter what you charge it to? I have just done a charge to 80%. After it reached that level, it then stayed charging, with little or no charge, for a further 35 minutes.

 

[Jomarkh]

I have read that the MG4 does balance at 80% but I think it does a full battery balance only after it has reached 100%.
Do you use a lot of rapid chargers?

 

[colsky]

I have read that the MG4 does balance at 80% but I think it does a full battery balance only after it has reached 100%.
Do you use a lot of rapid chargers?

No, I virtually always charge at home, and haven't used a rapid charger for a couple of months (and have done at least of couple of 100% charges since then).

 

[Tigger]

does the MG4 do a balance, no matter what you charge it to? I have just done a charge to 80%. After it reached that level, it then stayed charging, with little or no charge, for a further 35 minutes.

I found the same thing as you, also charging to 80% (see post #44 above). Last week I tried again charging to 60%, and got a similar result. The Trophy definitely seems to be equalising for at least 10 minutes after reaching the assigned charge level - I always get 1kwh or more in after that point. (I am not currently using rapid charging.)

Whether this is a 'full equalisation' I have no idea. Possibly not?

 

[colsky]

I found the same thing as you, also charging to 80% (see post #44 above). Last week I tried again charging to 60%, and got a similar result. The Trophy definitely seems to be equalising for at least 10 minutes after reaching the assigned charge level - I always get 1kwh or more in after that point. (I am not currently using rapid charging.)

Whether this is a 'full equalisation' I have no idea. Possibly not?

Not sure, but it can't be a bad thing.

 

[tsedge]

I found the same thing as you, also charging to 80% (see post #44 above). Last week I tried again charging to 60%, and got a similar result. The Trophy definitely seems to be equalising for at least 10 minutes after reaching the assigned charge level - I always get 1kwh or more in after that point. (I am not currently using rapid charging.)

Whether this is a 'full equalisation' I have no idea. Possibly not?

Same happens for me, it is definitely doing something as I have had it spend 20 minutes at a lower rate 1-2kWh before it shuts off.

 

[Tigger]

Same happens for me, it is definitely doing something as I have had it spend 20 minutes at a lower rate 1-2kWh before it shuts off.

Absolutely. And when I tried charging it to 60%, it carried on taking in 6.2kw for a full four minutes after reaching 60%, before dropping to 2-3kw for a bit, then tailing off. As you say, it is definitely doing something!

 

[IanMK]

Does the battery have to be charged to 100% to balance?

My electrician isn't coming to install my Zappi until next week so I thought I'd better use my granny charger today to top up from 30% to 50%. I used the iSmart app. A while after starting, the charging current according to iSmart had stabilised at 2kW. When I next looked, some time later, iSmart showed 50% SOC and 0.3kW charging rate. The granny indicator lights showed still charging. I was busy mowing the lawn, so left everything as it was. When I next looked, iSmart showed no charging current and the granny indicators showed not charging. Doesn't this suggest that an equalisation cycle took place at 50% SOC ?

 

[Archev]

My electrician isn't coming to install my Zappi until next week so I thought I'd better use my granny charger today to top up from 30% to 50%. I used the iSmart app. A while after starting, the charging current according to iSmart had stabilised at 2kW. When I next looked, some time later, iSmart showed 50% SOC and 0.3kW charging rate. The granny indicator lights showed still charging. I was busy mowing the lawn, so left everything as it was. When I next looked, iSmart showed no charging current and the granny indicators showed not charging. Doesn't this suggest that an equalisation cycle took place at 50% SOC ?

I think the iSmart has just limited the charge to the 50% you’ve set so it’s all shut down and granny’s put her feet up So all’s well I reckon. Well, other than not being neighbourly and cutting my lawn

 

[Tigger]

Doesn't this suggest that an equalisation cycle took place at 50% SOC ?

I think this is distinctly possible - see my post above, suggesting the same thing at 60%.

From a software point of view, there really isn't much difference between equalising at 100% or at some other percentage - but the truth is, we don't know.

My son has a Tesla and it behaves differently at 100%. It charges to 99%, then slows down to half speed (on a fast charger) creeping up slowly. Suddenly it stops charging, and announces that it has reached 100%. it can be in this slow state for 20-30 minutes. I have never watched it at 80% target (or whatever) - this happens at 6am, too early for me!

 

[Archev]

I think this is distinctly possible - see my post above, suggesting the same thing at 60%.

From a software point of view, there really isn't much difference between equalising at 100% or at some other percentage - but the truth is, we don't know.

My son has a Tesla and it behaves differently at 100%. It charges to 99%, then slows down to half speed (on a fast charger) creeping up slowly. Suddenly it stops charging, and announces that it has reached 100%. it can be in this slow state for 20-30 minutes. I have never watched it at 80% target (or whatever) - this happens at 6am, too early for me!

In my experience (with my MG5 but I understand all MG’s to be the same) the charging slows down markedly from around 85 to 95% and then takes a fair time to equalise the cells up towards 100%.
That’s why charging beyond 85% is pointless unless you mean to equalise as recommended monthly or so.

 

[Rolfe]

Can someone clarify for me just what is meant by "frequently" using rapid chargers, and how this affects the SR battery?

There is a rapid charger at the end of my street which is no more expensive than my domestic electricity supply. One charging regimen that seems convenient to me is to give the car as long as it's allowed on that charger (55 minutes, which gets about 50% battery capacity filled), then to plug it in to the granny charger at home just to bring it up to 100%, however much further that was. (The one time I tried it so far, I took it from 92% to full on the granny charger.)

Does this final stage on the granny charger balance the cells and so negate any imbalance from using the rapid charger?

 

[tsedge]

Can someone clarify for me just what is meant by "frequently" using rapid chargers, and how this affects the SR battery?

There is a rapid charger at the end of my street which is no more expensive than my domestic electricity supply. One charging regimen that seems convenient to me is to give the car as long as it's allowed on that charger (55 minutes, which gets about 50% battery capacity filled), then to plug it in to the granny charger at home just to bring it up to 100%, however much further that was. (The one time I tried it so far, I took it from 92% to full on the granny charger.)

Does this final stage on the granny charger balance the cells and so negate any imbalance from using the rapid charger?

The battery will balance with any AC charger (granny or home charger). Balancing does not happen with a rapid (DC) charger.