Long term storage effects on battery

[Hobbyist]

So rumours have it that there are loads of built Trophy Connects sitting in an empty airfield in China awaiting chips. Now we know that if leaving car unused for an extended amount of time may cause permanent damage to the HV battery. Tesla and Audi for example, recommend keeping the car plugged in, while MG recommends charging the car to at least 15%.

What are the chances the Connects arriving in the UK will have permanently damaged battery packs due to this long sitting around waiting for chips? How do we as consumers know if we get a lemon?

 

[N2STY]

Shouldn't be a problem with the 8-year battery warranty? If any full below 70% they will get replaced?

 

[Deleted member 7171]

Yes 70%, it is a very low bar. I think the battery would need to take some serious abuse to get to <=70% in 8 years.

See the last YouTube cast from 28 Feb(a while ago now, when's the next one!?) @Miles Roberts CG was asked about battery levels of new cars in storage.

 

[jds1972]

The lithium batteries will be fine, they will be at a mid state of charge essentially between 40-60% SOC.
A lithium Battery can be stored like this for an extremely long time with no ill effect/degradation. it is only a problem if they are at a high state of charge or low state of charge for a prolonged period. there are industrial Lithium modules within the warehouse where I work that have been there for over 2 years and on testing them the cells in the packs have dropped by around 25mV max in 2 years. this will not affect SOH.

 

[Maciej]

The lithium batteries will be fine, they will be at a mid state of charge essentially between 40-60% SOC.
A lithium Battery can be stored like this for an extremely long time with no ill effect/degradation. it is only a problem if they are at a high state of charge or low state of charge for a prolonged period. there are industrial Lithium modules within the warehouse where I work that have been there for over 2 years and on testing them the cells in the packs have dropped by around 25mV max in 2 years. this will not affect SOH.

Doesn't SR have different battery chemistry. If you store those shouldn't they be stored as close to full as possible?

 

[jds1972]

Doesn't SR have different battery chemistry. If you store those shouldn't they be stored as close to full as possible?

Regardless of the chemistry the storage characteristics are the same for lithium I think you are confused with the charging differences. The Sr needs to be fully charged during use to ensure the cells are balanced properly ?

 

[hmadsen]

Yes 70%, it is a very low bar. I think the battery would need to take some serious abuse to get to <=70% in 8 years.

See the last YouTube cast from 28 Feb(a while ago now, when's the next one!?) @Miles Roberts CG was asked about battery levels of new cars in storage.

In reality it will probably be more than 30% capacity they will need to lose, as the 4 kwh from the 72 real capacity and the 68 kwh usable capacity, is also partially used to make sure that the range does not drop for the first period of time.

Battery capacity loss is greatest in the start, so they mitigate this by having a bit of capacity in reserve to account for the first degradation.

Some of it is also used to that 0% SOT, is not really 0% SOT, as the battery is not very happy being THAT discharged.

 

[gide]

I'd like to ask here instead of starting an new thread, if this is possible.
We are going away for approx 6 months. The car is stored in our garage. It is a late 2002 model, 320km range.
Has anyone here experience with the best way to store the car. Should the tires be left at the usual pressure?
As it has a separate 12V battery I wonder if it should be on a trickle charger? Should the car be driven periodically and recharged by someone, or is that not necessary.
Anything else we should be aware of?
TA

 

[Coulomb]

It is a late 2002 model, 320km range.

I assume you mean a late 2022 model.

As it has a separate 12V battery I wonder if it should be on a trickle charger?

That should not be necessary, but I think it would be a great idea. I certainly would.

Should the car be driven periodically and recharged by someone, or is that not necessary

That should not be necessary. If possible, try to leave it at 50-60% state of charge.

 

[gide]

I assume you mean a late 2022 model.

That should not be necessary, but I think it would be a great idea. I certainly would.


That should not be necessary. If possible, try to leave it at 50-60% state of charge.

Thanks @Coulomb

Definitely 2022.

Is the 12V drawing from the main battery or is it charged when braking?
Still not sure what is the best solution?

We can drive for another coffee if the battery charge is a bit too high. Easy enough.

 

[aserraric]

The 12V battery is charged from the HV battery as long as the car is on ("Ready"). Kinda like the 12V battery in an ICE car is charged from the alternator while the engine is running.

 

[MickeySw]

As it has a separate 12V battery I wonder if it should be on a trickle charger?
TA

Yes, highly recommend. I was away for a month and used iSMART regularly to turn on the heater (which also charges the 12V battery) wouldn’t have lasted otherwise (MG5 FL).

 

[Ruislip Resident]

I saw a car with a small solar panel on the dashboard the other day. Presumably this is to keep the 12V battery charged if a car has been left. How does the panel get connected to the 12V battery to keep it charged. Do you have to do some special wiring inside the car or is there somewhere standard on all cars that you plug it into.

 

[Coulomb]

Do you have to do some special wiring inside the car or is there somewhere standard on all cars that you plug it into.

You need "always on" 12V, so I assume that they would use the OBD2 connector, like those gizmos that battery installers use to retain your radio stations and other settings when swapping out the 12V battery.

 

[gide]

Hello again, and, thanks for all the suggestions.
I contacted the car supplier and got the following. This is for storing the car for approx 6 months..
The advice is to have the main battery charged to 50 – 80%
Fit and use a battery maintainer(trickle charger) for the 12 volt battery.
Do not disconnect the 12 V battery(from the main battery) as it will cause multiple warning lights and then the vehicle would have to come in to have them cleared, so please keep the 12 volt battery connected up when using the battery maintainer.

 

[Tim Green]

I have three battery maintenance chargers from Halfords which work well. One led for mains on, and another that shows red for charging, and green for maintaining. They look like a plug-top and have a quick disconnect in-line plug so you can leave a permanent connection in place. I think they cost about £50.

 

[Ruislip Resident]

Where do you connect such things into your car?

 

[MickeySw]

Where do you connect such things into your car?

Usually straight onto the battery terminals..

 

[Chc mg]

Hello again, and, thanks for all the suggestions.
I contacted the car supplier and got the following. This is for storing the car for approx 6 months..
The advice is to have the main battery charged to 50 – 80%
Fit and use a battery maintainer(trickle charger) for the 12 volt battery.
Do not disconnect the 12 V battery(from the main battery) as it will cause multiple warning lights and then the vehicle would have to come in to have them cleared, so please keep the 12 volt battery connected up when using the battery maintainer.

We have a 2021 ZS EV. We're planning to go away for a year and just looking at our options for the car. I was curious what you ended up doing to store yours for 6 months, how it turned out and shutting your suggest doing differently?

Thanks!

 

[fred12345]

We have a 2021 ZS EV. We're planning to go away for a year and just looking at our options for the car. I was curious what you ended up doing to store yours for 6 months, how it turned out and shutting your suggest doing differently?

Thanks!

1 year is a long time but I'm sure some brand new cars sit around that long before being sold ... can you get someone to look after it for you? I would be a bit worried about leaving battery maintainer(trickle charger) for the 12 volt battery plugged in and connected to the car for a year, not keen of potential fire risk ... Maybe better to get a brand new 12v battery and make sure it's fully topped up before you leave? As to the main battery, I would charge it to 60-70% and leave it hoping for the best - unless you can get one of the neighbours to check it doesn't go below 40% and top it up every few months if needed? From memory, it's recommended to have the battery not lower than 50% when not in use for long periods of time.

Found one post from 2020 on Speak EV forum:
BarryH
255 posts · Joined 2019

#12 · May 15, 2020

"Lithium ion battery cell chemistry if not used and stored ie the car is parked up for a substantial time should be at half charge state so that the Cathode and Anode are protected. In practice, since HV battery will slowly discharge, charging to 60 % SOC would be ideal so thereby allowing for self-discharge to 50% or just below over time. Depending on how the low voltage 12v electronics are managed the HV Battery may periodically be used to power the DC-DC Converter to top up the 12v battery. Tesla's for instance do this quite often and the HV will loose about 1% per day. MG ZS I believe doesn't fire up the DC-DC Converter automatically when stored and it is activated only when car in READY state. Potential therefore the 12volt battery can run down. You could consider connecting a solar top-up charger if car parked for very long periods, although since the UK models don't have the App and live connection, which is found on Asian model, battery drain should be less significant."