Battery equalisation

[wattmatters]

Our Essence 64 charging one day last week. Variable power delivery based on solar.

See the small tail current at the end when main charging was completed:

Zoom in on that tail current:

 

[Museruk]

I've got an Ohme charger and I used it for four months prior to going onto Intelligent Octopus Go tariff. During these months battery would equalise once charge reached 100%. Basically it would carry on trickle charging for a couple of hours at about 0.1kw or so. Since going onto IOG in July, once charging rate gets down to about 1kw it shuts off and stops charging, and so effectively is not balance charging. I believe this may be to prevent off peak rates being given for more than is necessary if smart charging outwith guaranteed off peak hours (another story). I've researched this and accordingly a thread on the IOG facebook group you have to invoke Max Charging to allow a balance charge, effectively cancelling off peak smart charging. However if done during guaranteed off peak hours still charges at off peak rates. I shall be trying this out tonight to see if I get my first full balance charge in 6 months.

I’m also on IOG tariff, but we have a Zappi charger (when Octopus tried to install the Ohme charger it did not perform due to our flaky mobile signal - hence we ended up with the Zappi as it uses a WiFi connection instead for linking to Octopus).
Anyway, Zappi is a MyEnergy product and the app they supply shows the recent charge history, so I can clearly see that it is not doing the necessary low (few hundred watts charge) at the end of a 100% charge.
I contacted Zappi support and they claim that Zappi should be capable of doing this balancing charge. Also MG, via the main dealer claimed it should work.
However I believe they are wrong as I have not seen the evidence that it is balancing.
I will attempt a ‘Boost’ charge on the Zappi during the day, when already at or near to 100% charge.
Although this will be at the day rate, if it works, it should only be a relatively low cost as it should only draw a few hundred watts.
Will report what happens!

 

[Kithmo]

It is in the manual ??‍

I can't see anything in the manual (downloaded from MG) about taking the battery down to 10% before equalising, is there another later version of the manual ?

 

[fnegroni]

 

[olliewebb]

3kW from a granny? Highly unlikely. More like 2kW at most

Lucky to get 1.8kw really.

 

[mg4mc]

I've got an Ohme charger and I used it for four months prior to going onto Intelligent Octopus Go tariff. During these months battery would equalise once charge reached 100%. Basically it would carry on trickle charging for a couple of hours at about 0.1kw or so. Since going onto IOG in July, once charging rate gets down to about 1kw it shuts off and stops charging, and so effectively is not balance charging. I believe this may be to prevent off peak rates being given for more than is necessary if smart charging outwith guaranteed off peak hours (another story). I've researched this and accordingly a thread on the IOG facebook group you have to invoke Max Charging to allow a balance charge, effectively cancelling off peak smart charging. However if done during guaranteed off peak hours still charges at off peak rates. I shall be trying this out tonight to see if I get my first full balance charge in 6 months.

The charger does not cut off below 1kW, it cuts off at the end of the schedule. If you are going to do a balance charge, then you need to add an additional 5% to the charge request above what you actually need. This gives you more scheduled time to complete the balance.

Mine will happily balance charge at a few hundred watts without having to invoke max charge.

Even if you do have to invoke max charge during the day and get charged at the day rate, it isn't consuming much power to do the balance bit, so it'll cost you pennies.

 

[Museruk]

View attachment 22129

This is terrible English and also very ambiguous.
It could refer to charging at a low rate (10% or I grid) or, as many people appear to have assumed, to perform a charge from less than 10% to 100%!
I have requested clarification from the main dealer, but not received a satisfactory answer or clarification of this statement in the manual.

 

[skynett]

I’m also on IOG tariff, but we have a Zappi charger (when Octopus tried to install the Ohme charger it did not perform due to our flaky mobile signal - hence we ended up with the Zappi as it uses a WiFi connection instead for linking to Octopus).
Anyway, Zappi is a MyEnergy product and the app they supply shows the recent charge history, so I can clearly see that it is not doing the necessary low (few hundred watts charge) at the end of a 100% charge.
I contacted Zappi support and they claim that Zappi should be capable of doing this balancing charge. Also MG, via the main dealer claimed it should work.
However I believe they are wrong as I have not seen the evidence that it is balancing.
I will attempt a ‘Boost’ charge on the Zappi during the day, when already at or near to 100% charge.
Although this will be at the day rate, if it works, it should only be a relatively low cost as it should only draw a few hundred watts.
Will report what happens!

Think my zappi doesn't do this trickle charge either. Will have to do a test at or close to ? charge

 

[Rolfe]

Lucky to get 1.8kw really.

I regularly see 1.87 Kw. I don't think I've ever seen 1.9 though.

Here is a thread where I described doing this long slow charge on my SE SR.

A long time on a granny lead | MG4 EV (2022 to 2025) Forum

In another thread someone pointed out that MG recommend that cars should be charged from 10% to 100% on a "slow charger" every three to six months. I didn't think I needed the car today, so since I was down to 9% yesterday afternoon I thought I'd give it a try. I started the charge about 4.30...

www.mgevs.com

I used the granny lead but as far as I know any AC charger would be fine.

 

[Surfdog]

The charger does not cut off below 1kW, it cuts off at the end of the schedule. If you are going to do a balance charge, then you need to add an additional 5% to the charge request above what you actually need. This gives you more scheduled time to complete the balance.

Mine will happily balance charge at a few hundred watts without having to invoke max charge.

Even if you do have to invoke max charge during the day and get charged at the day rate, it isn't consuming much power to do the balance bit, so it'll cost you pennies.

Tried it last night and still didn't trickle charge. I always add an extra percent onto charge request. Has never trickled charged since going into IOG but did prior to this.

 

[Tight Git]

I’m also on IOG tariff, but we have a Zappi charger (when Octopus tried to install the Ohme charger it did not perform due to our flaky mobile signal - hence we ended up with the Zappi as it uses a WiFi connection instead for linking to Octopus).
Anyway, Zappi is a MyEnergy product and the app they supply shows the recent charge history, so I can clearly see that it is not doing the necessary low (few hundred watts charge) at the end of a 100% charge.
I contacted Zappi support and they claim that Zappi should be capable of doing this balancing charge. Also MG, via the main dealer claimed it should work.
However I believe they are wrong as I have not seen the evidence that it is balancing.
I will attempt a ‘Boost’ charge on the Zappi during the day, when already at or near to 100% charge.
Although this will be at the day rate, if it works, it should only be a relatively low cost as it should only draw a few hundred watts.
Will report what happens!

When I get home I will have to check to see if mine has done any balance charges since I went onto Octopus Intelligent a few weeks ago.

The other alternative is to get the granny charger out and do a balance charge between 11.30 and 5.00am.

I'm currently on a Connected Kerb 7kW and it's been doing a balance for about 50 minutes at 20 watts so it looks like it needed one!

 

[siteguru]

200W? Does the app show 0.02kW? That's 20W (which is a quite typical balance charge level for the SE SR).

 

[Tight Git]

200W? Does the app show 0.02kW? That's 20W (which is a quite typical balance charge level for the SE SR).

Apologies had the decimal point in the wrong place - it was 0.02 and I was thinking 200 watts so I've edited my post.

Having got my computer out I cannot see any evidence of a balance charge in any days when IO was in control of the charging. However when I hit a boost charge before I left home it did a balance charge which is just possible to make out on the Myenergi graph and shows 0.674 kW for 4am and 0.024 kW at 5am.

Interesting to see if anyone can verify if IO can do a full balance charge while under their control.

 

[siteguru]

I think a few people have mentioned issues with balance charging on some of he Octopus tariffs.

 

[wattmatters]

View attachment 22129

I interpret that to mean it's just wants a slow full charge every so often in order to allow the BMS to perform a cell balance. i.e. a DC charge rate at 10% of max charge rate or via a grid (AC) supply which uses the on-board charger (which is slow charging).

 

[Ayoull]

That's a balance charge at the end on my podpoint, it fluctuates between 0.02kW to 0.6kW

 

[Ian Key]

I wonder if the problem is with Octopus. You tell Octopus you want the battery charged to 100% and it does so stopping when the car tells it its at 100% and not continuing with a balance charge.

I have a Zappi but I'm not with Octopus and have no problems with balance charging.

 

[fnegroni]

I interpret that to mean it's just wants a slow full charge every so often in order to allow the BMS to perform a cell balance. i.e. a DC charge rate at 10% of max charge rate or via a grid (AC) supply which uses the on-board charger (which is slow charging).

Granted it’s broken English.
Maybe rushed by a Chinese techie who realised this was missing from the manual and did their best job to put it in there!

for me it means: every 3 to 6 months perform a slow continuous charge from less than 10% remaining charge (as indicated in the app by 1 square full out of 10 squares) to 100% fully charged.

 

[mg4mc]

I wonder if the problem is with Octopus. You tell Octopus you want the battery charged to 100% and it does so stopping when the car tells it its at 100% and not continuing with a balance charge.

I have a Zappi but I'm not with Octopus and have no problems with balance charging.

AFAIK the car doesn't tell anything about its SoC when AC charging. It just draws current or not - after the initial handshake to let each other know they are connected.

 

[tsedge]

AFAIK the car doesn't tell anything about it's SoC when AC charging. It just draws current or not - after the initial handshake to let each other know they are connected.

Yes, it isn't possible to know the car's SoC via AC charging, so the Zappi can't know when to stop on that basis. The delta charge percentage is based on the overall pack size / charge rate.