Granny charger

[Headgas1]

Hi all I hope everyone is doing well, a question about my granny charger I use mine all the time to charge the car but it’s all guesswork as to how long is needed and I tend to leave it overnight and it has just occurred to me that I may have done the equalisation charge twice in 2 weeks.

Does the car only do an equalisation if it’s needed ?? If not and it automatically goes into the equalisation does it do any harm to do it regularly??

thanks in advance Phil

 

[Chrispydoc]

I used to do the same....was never an issue over the 20 months I had the car.

 

[macd2401]

A balanced battery is a good thing to have. The manual recommends a balancing cycle once every month or so, but it certainly won't do any harm if you do it more often.

 

[Headgas1]

A balanced battery is a good thing to have. The manual recommends a balancing cycle once every month or so, but it certainly won't do any harm if you do it more often.

Cheers bud that’s reassuring ????

 

[Jomarkh]

My neighbour just plugs her car in most nights and that's on a 7.5kw unit.
The car just takes what it wants then turns the charger off

 

[JodyS21]

I only does the balancing (after it's reached 100% charge) if it deems it necessary.
It may only run for minutes if it's not very imbalanced, otherwise could be several hours.
It's good to let it do it whenever you can, certainly isn't a negative thing to do.

 

[Headgas1]

Thanks @JodyS21 it’s always helpful when somebody like yourself can give the answer that I can’t find in the manuals cheers ???

I only does the balancing (after it's reached 100% charge) if it deems it necessary.
It may only run for minutes if it's not very imbalanced, otherwise could be several hours.
It's good to let it do it whenever you can, certainly isn't a negative thing to do.

 

[Kithmo]

I only does the balancing (after it's reached 100% charge) if it deems it necessary.
It may only run for minutes if it's not very imbalanced, otherwise could be several hours.
It's good to let it do it whenever you can, certainly isn't a negative thing to do.

I would be interested to know how far out of balance the battery has to be before the car determines whether it needs balancing or not.
Mine always seems to be 40mV out after balancing, yet it only balances for 10-20 minutes after charging. Is my car saying 40mV is acceptable and stops at that ?

 

[Phil Hayward]

For some time I put my car on charge overnight when the battery gauge went from 3 to 2 segments, about 30%, it was usually about 80% in the morning. I balanced every 10th half charge. After finding out it has an iron phosphate battery I am not so careful, as they have a longer life and do not suffer as much degradation when fully charged and discharged. In the summer I keep the battery well up in case I wanted to go on a journey. Charging to 100% does not fully charge the battery as there is buffer, at the top end this was recently lowered by 5v.
I still only charge to 80% as I think it is kinder to the battery, most common advice is not to worry as the BMS looks after the battery, Tesla use some iron phosphate and recommend a 90% charge.

 

[Coulomb]

After finding out it has an iron phosphate battery I am not so careful,

It can't be iron phosphate (LFP chemistry). The battery charges to 450 V or more, and we know it has 108 cells (9 modules each of 12 cells in series), and 450 / 108 = 4.17 V per cell average. That's way over LFP's voltage range; they top out at about 3.65 V.

I'm 99% sure that the present MG ZS EVs are all NMC chemistry. The forthcoming ~51 kWh model might end up being LFP.

 

[Phil Hayward]

Thanks for the correction - NMC, I will keep my battery between 30% and 80% when convenient.

 

[Headgas1]

Thanks for the correction - NMC, I will keep my battery between 30% and 80% when convenient.

Why keep the battery between 30 & 80 % ? @ phil Hayward

 

[JimB]

Specs from MG EU site - note different battery chemistry between standard and long range models.

Discover MG5 Electric

World's first 100% electric stationwagon. Comfortable range with a fast charging capability.

mgmotor.eu

 

[JodyS21]

It can't be iron phosphate (LFP chemistry). The battery charges to 450 V or more, and we know it has 108 cells (9 modules each of 12 cells in series), and 450 / 108 = 4.17 V per cell average. That's way over LFP's voltage range; they top out at about 3.65 V.

I'm 99% sure that the present MG ZS EVs are all NMC chemistry. The forthcoming ~51 kWh model might end up being LFP.

I can't remember what it said now, but I did see the voltage shown on the display in one of the videos of the new ZS

Just seen it: 350V at 40% battery (@ 2Amps). Is that different??

 

[Coulomb]

350V at 40% battery (@ 2Amps). Is that different??

I believe so. That would be 3.24 VPC for a 108 cell battery, which seems too low for NMC at 40% SoC.

 

[Phil Hayward]

Why keep the battery between 30 & 80 % ? @ phil Hayward

The battery will last longer if not fully charged and discharged.
I found this estimate of battery life.

 

[Gomev]

The battery will last longer if not fully charged and discharged.
I found this estimate of battery life.

Sorry not seeing where that table shows charge level %age

 

[Phil Hayward]

4.2 v per cell is about 100% this is the voltage I use for my tool batteries.
this is on MG's web site,
"
There are a number of tips that you can use to try and increase your electric car battery life:

• Charge the electric car battery between 20%-80% - The lifespan of the battery pack often depends on how much it’s charged. You can extend the life of the batteries by only charging them between 20% and 80% and trying not to let them drop below 50% too often. Going beyond these limits can increase the rate that the battery deteriorates over time.

 

[Headgas1]

@Phil Hayward some good info there bud cheers

 

[JodyS21]

I believe so. That would be 3.24 VPC for a 108 cell battery, which seems too low for NMC at 40% SoC.

Found another voltage/SOC data point from a video, 389V @83%.
So it definitely looks like they are using the cells in a different arrangement/using different chemistry. A different arrangement of cells is almost a certainty I'd have thought.
I wonder if the new voltage is related to the new motor it is using - it must be different motor mustn't it to be using a lower normal voltage range?

It appears like a step backwards to lower the voltage, I thought the future was higher battery pack voltages e.g. 800V so that they can be charged quicker on DC. My knowledge on this area is minimal though.