Charge to 80% or 100%

[dave4]

Hi, I have just bought a ZS short range. Please could you advise on changing the battery.
Some say charge to 100%
Others say only to 80%.
Same say the short range zs has a different battery to the long range zs.
And only the long range should be charged to 80% unless doing a long journey.
Please could you advise.

 

[DB Go Rex]

The battery chemistry is different with the SR. It's LFP.

The bottomline is battery percentage SOC is calculated based on a voltage drop curve. That curve is a lot flatter on LFP chemistries, so charging to 100% more regularly assists the BMS in its SOC calculation. Not doing that reasonably regularly could lead to the SOC not being accurate enough.

Battery life is a different matter. It gets complicated. There is some evidence to say LFP copes better at higher states of charge. But ultimately both benefit from not being at high states of charge for long periods.

This Engineering Explained video explains that it isn't as simple as a lot of people make out:

 

[dave4]

Hi, I have just bought a ZS short range. Please could you advise on changing the battery.
Some say charge to 100%
Others say only to 80%.
Same say the short range zs has a different battery to the long range zs.
And only the long range should be charged to 80% unless doing a long journey.
Please could you advise

Thanks for the video, I watched it twice and think maybe I will charge it alternatively, 80% then next time 100% and so on. Still not sure if that's correct. Hopefully it is as I do around 40 miles a day.

 

[KrispiiDuck]

Jumping onto this thread, I've now charged twice, first time to 100% as I didn't know how not to, and tonight to 86% as that's when I noticed how much juice was in it.

Is there a way to set the short range version to charge only to 80%, as I'm struggling to find it...
Thanks in advance.

 

[Steve Kaye]

The battery chemistry is different with the SR. It's LFP.

The bottomline is battery percentage SOC is calculated based on a voltage drop curve. That curve is a lot flatter on LFP chemistries, so charging to 100% more regularly assists the BMS in its SOC calculation. Not doing that reasonably regularly could lead to the SOC not being accurate enough.

Battery life is a different matter. It gets complicated. There is some evidence to say LFP copes better at higher states of charge. But ultimately both benefit from not being at high states of charge for long periods.

This Engineering Explained video explains that it isn't as simple as a lot of people make out:

I dont understand the terminology
What is SR.. LFP..SOC..BMS?

 

[Coulomb]

Is there a way to set the short range version to charge only to 80%,

It's "standard" range ?.

Alas, no. The claim is that LFP chemistry suffers no degradation from charging to 100%; personally I disagree, as do others. But rather than give you the choice a recommendation, they just disable the charge limit function, without taking it off the charging page altogether.

What is SR.. LFP..SOC..BMS?

SR: Standard range.
LFP: Lithium Ferrous Phosphate; it's the type of battery in standard range MGs. It's safer, cheaper to manufacture, but less energy dense.
SOC or SoC: State of Charge. 100% means that the battery is full, 0% means it's empty. Not to be confused with SOH or SoH: State of Health: 100% means that the battery is new and has not lost any capacity; 80% means it's lost 20% of its capacity, and therefore of its expected range when fully charged. So a 64 kWh battery when new is effectively a 51.2 kWh battery when it reaches 80% SoH (hopefully near the end of the car's useful life).
BMS: Battery Management System. All lithium batteries (LFP, NMC, or other chemistries) require a management system to keep the individual cells within the battery safe, healthy, and balanced.

See also Acronyms are confusing and several other topics; the search ?button is your friend.

 

[ChargeMaster]

I've been alternating between 80% and 100% charges too, seems like a good compromise.

 

[Lovemyev]

I've been alternating between 80% and 100% charges too, seems like a good compromise.

Long range model ZS EV with NMC.
Unless you require all of that range provided from a 100% charge, then charging to 80% SOC is more suited for regular charging and then maybe charge to 100% less frequently.
This is recommended for long term battery health on NMC packs.
This supports the fact that on the long range model, the manufacturer has provided the facility of a slide bar control to make this possible.
The standard range with LFP pack not have this feature of course as it is intended that owners charge to 100% on every single charge cycle.
LFP batteries are reported to struggle predicting range estimates when charged to below 100% apparently ??.

 

[Whiskery]

I've had a Standard Range model since mid-2022 and have consistently charged (at home) to 100% as I do need the range. Only time I haven't done so is if I'm on a public charger and I tend to unplug at around 80% to free up the charger.

 

[DB Go Rex]

I dont understand the terminology
What is SR.. LFP..SOC..BMS?

SR = Standard Range (the 51kwh ZS)
LFP = lithium iron phosphate ( F - Latin iron, ferros)
SOC = State Of Charge
BMS = Battery Management System (the control system that manages the charging, discharging, temperature and general health of the battery in the car.)

 

[fred12345]

Jumping onto this thread, I've now charged twice, first time to 100% as I didn't know how not to, and tonight to 86% as that's when I noticed how much juice was in it.

Is there a way to set the short range version to charge only to 80%, as I'm struggling to find it...
Thanks in advance.

You don't have to charge to 100% except for balancing about once every 4-6 weeks or so - read the manual about the battery care. Standard range is fine charging to 100% but I tend to charge to about 70-ish % unless I need to go somewhere further away. I leave it down to about 30% or so and then add another 30% overnight on cheap rate as I mainly drive locally so 30% top-up is enough...

There is anther thread about balancing, search the forum but don't worry too much about the battery - drive and enjoy the car.

 

[KrispiiDuck]

Thanks everyone - really appreciate your time in replying with some great advice

 

[Mg4me]

Hi, I have just bought a ZS short range. Please could you advise on changing the battery.
Some say charge to 100%
Others say only to 80%.
Same say the short range zs has a different battery to the long range zs.
And only the long range should be charged to 80% unless doing a long journey.
Please could you advise.

I've the zs EV (short range) for 12 months now. I tend to leave it in an overnight 7kW charger when it gets very low, about thrice a fortnight. I've discovered that to keep the range like new (320km or so), Once a month I run the car to low and then snail-charge at home (1.5kW) right up to full. The SLOWER you charge it and/or the warmer you charge, the better range. It has now become apparent that the MG position on charging the short range is to go to 100% every time, which is no doubt why they took out the 'charge to 80%' option from the charge settings on console and app.
Also note: the faster you charge (eg 50kW) the lower range you will get. In winter on fast charge, I've gone as low as 237km. NIGHTMARE for Australian interstate trips.

 

[DB Go Rex]

. It has now become apparent that the MG position on charging the short range is to go to 100% every time, which is no doubt why they took out the 'charge to 80%' option from the charge settings on console and app.
Also note: the faster you charge (eg 50kwh) the lower range you will get. In winter on fast charge, I've gone as low as 237km. NIGHTMARE for Australian interstate trips.

The manual doesn't say go to 100% every time.

The rate of charging has very little to do with how much range you will get.

If anything, a lengthy DC rapid charge session will warm the battery up a bit on a cooler day, putting it at a better operating temp.

Your comments about range are a bit off for me in general. The GOM is estimating the range you might get on the basis of what you've previously been consuming to predict what you might get with the remaining SoC. What the GOM is giving you isn't what you will necessarily get.