Keeping your electric car’s battery in tip top condition is important at the best of times, let alone when it’s parked up idle. Aside from nationwide lockdowns, there are numerous reasons why cars are left parked for extended periods, from heading off to far flung places during happier times to only using a car (such as a Renault Twizy) during the summer.
The following guidance should help you maintain your vehicle’s battery in its best possible condition, and avoid premature degradation. Guidance varies from car to car, just as hybrid, plug-in hybrid or battery electric powertrains do. As a general rule, cars are equipped with both a traction battery and a 12V battery to power ancillary systems such as the radio and headlights.
Please note that this list is being updated as and when we receive information from manufacturers, so check back regularly for additional information.
Manufacturer
Audi (and other Volkswagen Group vehicles)
e-tron & e-tron Sportback – If the vehicle is not being used for long periods of time, the high-voltage battery must be charged after four months at the latest or the vehicle must be continuously connected to a power source. You can set the charging target, meaning you can set the maximum charge level to which the high-voltage battery should be charged. The charging target can be set between 50% and 100%. For daily usage, Audi recommends setting the charging target at 80%. This can extend the service life of the high-voltage battery. Before long trips, Audi recommends setting the charging target at 100% for the highest possible range. Otherwise, the high-voltage battery could become damaged.
A3 e-tron and other plug-in Hybrid models – Be sure to charge the high voltage battery be- fore leaving the vehicle parked and unused for a longer period of time. Ideally the high-voltage battery should have a charge level between 40% and 60% when parked for a Long time.
If the battery charge level is below 3 %, never park the vehicle for more than 21 days without charging the high-voltage battery. Should you have to park the vehicle for a long time, make sure that the charge level is sufficient to help prevent the battery from ageing prematurely.
Frequent and consecutive charging of the high-voltage battery when the charge level is above 98% can also decrease the capacity of the high-voltage battery. Make sure the charge level is below 98% when you start the charging process.
Should the vehicle be parked for longer than 2 days at temperatures below -25°C (-13°F), the high-voltage battery could freeze and not be able to provide energy to the electric motor. The battery will start working again, once it warms up. The battery can be warmed up when the outside temperature rises or when the vehicle is garaged appropriately. The battery will also warm up when being used (switching on the air conditioner, the heater or by driving the vehicle). Should you have to park your vehicle at very low temperatures for longer than 1 day, make sure that the high-voltage battery does not freeze by parking the vehicle in a garage that is heated or protected from the outside temperature.
The high-voltage battery can be damaged and the capacity can be decreased when the vehicle
is parked for longer than 24 hours when the ambient temperature is higher than 48°C (118°F). Always make sure that the high-voltage battery is not exposed to temperatures above 48°C (118°F) for a long time.
For other models see owner’s manuals available at: https://www.audi.co.uk/owners-area.html
Bentayga Luxury Hybrid – Before the vehicle is placed in storage, make sure of the following:
Before storing the vehicle, ensure the interior and exterior are clean and dry, and free from damage. The storage area of the vehicle should be dry and well-ventilated.
Before storing the vehicle, carry out the following procedures:
• Increase the tyre pressures to 60psi (4.1bar, 420kPa).
• Increase the full size spare tyre pressure to 60psi (4.1bar, 420kPa). The temporary-use spare wheel does not need to be inflated.
• Park the vehicle on tyre cradles.
• Check the levels of the engine oil, engine cooling system reservoir, braking system reservoir, and top-up as necessary.
• Ensure all electrical equipment is switched off.
• Leave all air vents open to aid free circulation of air.
Battery Conditioner/charger (when fitted)
WARNING: If the vehicle is to be stored in this condition for periods in excess of three months, it is recommended that an authorised Bentley retailer is contacted, who will give advice and guidance on the correct additional procedures for longer storage periods.
Caution: Disconnect the battery conditioner/charger before driving away. Only use a genuine Bentley battery conditioner/charger as supplied; a ‘universal’ battery conditioner/charger could cause damage to the vehicle’s electrical system. Contact your authorised Bentley retailer for further information.
Note: The battery conditioner/charger may not charge a battery from a low state of health, instead it should be viewed as a tool to maintain a healthy battery.
All electric and plug-in hybrid models – An electric vehicle or hybrid high-voltage battery will last for weeks when not being driven, as a Li-ion battery has a low self-discharge rate. The car can be left connected to a home charger ‘wall box’ as charging will stop once the battery is fully charged.
A BMW’s Battery State of Charge can be seen and monitored in the vehicle or via the Connected Drive app on a smartphone.
Do not park the vehicle for longer than 14 days if the electric range is less than 6 miles (10km).
PHEV models – Ideally, think about storing your BMW with a full tank of fuel to avoid any condensation build-up.
General storage advice – Check the tyres to make sure they are at the recommended pressures. Proper inflation helps prevent cracking of the sidewalls and flat spots. Check the valves and valve caps for leaks and that the valve caps fit properly.
If storing the vehicle for longer than three months, increase the tyre pressure to 50PSI (3.5 bar). Remember to adjust the pressures to the recommended values prior to driving the vehicle once out of storage.
Your brakes will be affected by an extended period of non-use. You may see surface rust on the brake disc after even a short period of time. With prolonged periods of non-use, brakes and handbrakes can become corroded and require replacement. Using your car at intervals, sufficient to charge the battery for example, should keep your brakes corrosion-free. Remember to drive with caution if your brakes show signs of light surface corrosion as stopping distances may temporarily be extended. If you have any concerns about corrosion it is important to seek expert advice.
The general advice is to wash your car every 1-2 weeks where possible. Benefits may include removing any external influences that may cause damage to the paintwork (e.g. bird lime), clearer visibility which contributes to safer driving and of course, keeping your BMW looking at its best!
C-Zero – To optimise the service life of the main battery, recharge it completely every two weeks.
For a complete charge, follow the normal charging procedure (domestic electricity supply) without interruption until it stops automatically (confirmed by the charging warning lamp going off in the instrument panel).
In addition, every three months, make sure that you charge the main battery fully starting from a charge level less than or equal to 2 bars.
DS 3 CROSSBACK E-TENSE, DS 7 CROSSBACK E-TENSE 4×4 – BEV and PHEV batteries are best charged to 80% (not 100%, ideally).
If there is the opportunity to use the vehicle for food runs, etc. it is good practice to run it every 2 weeks.
The DS 7 CROSSBACK E-TENSE 4×4 could be trickle-charged, but as it has two batteries (traction and 12V) this won’t be better than to occasionally run the vehicle.
DS offers a service to its customers who have a self-induced issue, so they are covered by the RAC.
One other option, least recommended is to open the bonnet and un-clip the 12V battery if garaged and secure.
Ford
All models – For longer, trouble-free operation, keep the top of the 12V battery clean and dry and the battery cables tightly fastened to the battery terminals. If any corrosion is present on the battery or terminals, remove the cables from the terminals and clean with a wire brush. You can neutralise the acid with a solution of baking soda and water. Ford recommends that you disconnect the negative battery cable terminal from the 12V battery if you plan to store your vehicle for an extended period.
While there is no specific information available in the various handbooks relating to storing your Ford Hybrid or PHEV vehicle for a long period of time, there is information relating to disconnecting the high-power battery if necessary and instructions on how to replace the 12V battery too.
Ford owner’s manuals are available to download or view on its website: https://www.ford.co.uk/owner/my-vehicle/download-your-manual
Honda
All models – Customers can trickle charge their 12V batteries in their cars, though they have to completely remove the connection to the car by disconnecting the leads from the battery to the vehicle before doing so – it is important to disconnect the battery when charging as otherwise you can damage the vehicle’s electrical systems. Please follow the guidance as set out in the owner’s manual. When reconnected, the vehicle needs to be driven at more than 12mph to reset the indicators required for ADAS (Advanced Driver Assistance Systems).
Hybrid models – The high-voltage battery gradually discharges even if the vehicle is not in use. As a result, if your vehicle is parked for an extended period of time, the battery charge level will become low. Extended periods of time at a low state of charge will shorten battery life. To maintain the battery state of charge, drive your vehicle for more than 30 minutes at least once every three months.
Extreme high temperatures can affect the battery life. You can minimise the effects by parking the vehicle in the shade during the summer.
Be careful not to let the high-voltage battery drain too much. If the battery level becomes close to zero, it will make it impossible to start the power system.
You cannot trickle charge the main battery in a Honda Hybrid. It is powered by the car’s internal combustion engine and will always rest between 20-80% charge and will never go completely flat. It will simply charge when the car is taken out the next time it is driven.
Hyundai
All models – Aside from the 12V battery, customers need not worry about high-voltage battery care other than to not allow it to remain empty for extended periods. Being left fully charged isn’t going to cause any issues as the battery management system will still ensure everything is kept in check. Customers may want to leave the car plugged in, allowing the battery management system to look after everything it needs to.
For the 12V battery, there are two considerations:
1. Some Hyundai electrified vehicles have a “12V reset” button in the cabin alongside the main controls. In the event that the 12V battery goes flat, this button can be pressed and the main high voltage battery will “jump start” the 12V battery. Essentially there’s no need for any maintenance, and full operating instructions are in the owner’s manual.
2. For cars that don’t have a reset button, a conventional good-quality trickle charger can be used. Hyundai says owners must ensure connections are correctly made (+ve to +ve, and -ve to -ve) as damage to the electrical systems is possible through incorrect connection.
Jaguar
I-Pace – In the event of long-term storage, make sure to charge the high voltage battery every 30 days.
CAUTION: Make sure that the high voltage battery is charged to a target of 30% and no more than 60%. Failure to do so may result in damage to the battery.
When charging the high voltage battery, it is recommended to connect the vehicle’s charging cable to an external charging station. While the battery is charged, the instrument panel displays the current high voltage battery charge level.
The current high voltage battery charge level can also be viewed in the instrument panel’s power gauge display.
CAUTION: Make sure that the 12V battery remains connected, and in a sufficiently charged state, during the storage period.
Kia
All models – Always ensure that all doors and tailgate are closed fully, interior lights are switched off and the car is locked with the remote transmitter. This will not only ensure the vehicle security but also minimise drain on the battery.
Niro Hybrid & PHEV – Avoid turning on then off the engine until it has reached temperature.
Niro PHEV – If suitable battery charging equipment is available, charge the 12V battery at regular intervals (recommended every two weeks). Alternatively use an intelligent charger which can be connected permanently and will periodically monitor / maintain battery condition.
If you are not able to use a battery charger, start the engine and allow it to idle for 20 minutes every two weeks. Stay with the vehicle while doing this, and turn off all unnecessary electrical items, such as lights and heated screens.
Should you find your 12V battery has already discharged, recharge the battery using a battery charger if available. If you use a jump pack or jump leads to start the vehicle, refer to the Owner’s Manual for further guidance, paying particular attention to how and where to connect leads. The Intelligent Stop Go (ISG) system (where fitted) can be damaged if chargers or jump leads/packs are incorrectly connected.
Niro Hybrid – Niro self-charging hybrid models (18MY onwards) are equipped with a 12V Lithium Ion battery and a battery reset switch. You can help preserve your 12V Lithium Ion battery charge by starting the engine and allow it to idle for 20 minutes every two weeks. Stay with the vehicle while doing this, and turn off all unnecessary electrical items, such as lights and heated screens.
On no account should a charger, jump pack or jump leads be attached to your vehicle. Instead, if the 12V lithium-ion battery is discharged, it can be reset by pressing the battery reset switch. Please refer to the Owner’s Manual for more information.
e-Niro, Niro PHEV, Soul EV – For EV & Plug-in Hybrid vehicles it is recommended that the high voltage battery is left in a fully charged state.
Charge the car then leave it and check the charge status every so often. If you do leave it plugged in, the vehicle will shut down the charging when full so no problems should occur. For those without home charging, they should visit a charge point while following government rules relating to the current coronavirus lockdown rules.
Refer to website: https://www.kiapressoffice.com/en-gb/releases/1172
Mercedes-Benz (and smart electric/EQ models)
All electric and plug-in hybrid (EQ) models – When a customer activates their “Mercedes me” account, they can receive SMS or Mercedes me app alerts if either the 12V battery or high-voltage battery becomes critically low – prompting them to recharge the high-voltage battery.
Similar to a 12V battery, it is normal for a high voltage battery to lose a little charge when the vehicle is stationary for prolonged periods – but this depends on a variety of factors. Therefore, Mercedes-Benz generally doesn’t recommend leaving, for example, an EQC stationary with a low battery and unplugged for prolonged periods – but customers can get alerts sent via Mercedes me informing them if the battery becomes critically low.
When an EQC or EQ Power vehicle is put on charge, it also internally supports and charges the 12V battery – so a separate charger would not be required.
It is safe to leave an EQC and our EQ Power plug-in hybrid vehicles plugged in for “long periods” if desired.
On request customers can receive a push notification when the charging process starts and ends.
All new EQCs and Mercedes-Benz EQ Power vehicles come with complimentary Roadside Assistance within the first three years of ownership and every year thereafter when the vehicle is serviced within the Mercedes-Benz network. This includes assistance in the event of a flat battery.
Mercedes-Benz customers can find out specific battery and charging information within the respective model owner’s manuals.
MG
ZS EV – The high voltage battery should have a minimum charge of 15% if the car is left to stand.
The 12V battery should not be neglected. MG recommends a trickle charger if the car is not to be used for some time. It will maintain the 12V battery in good condition. The customer should always follow the details in the trickle charger provider’s user guide.
Mitsubishi
i-MiEV – To optimise the service life of the main battery, recharge it completely every two weeks.
For a complete charge, follow the normal charging procedure (domestic electricity supply) without interruption until it stops automatically (confirmed by the charging warning lamp going off in the instrument panel).
In addition, every three months, make sure that you charge the main battery fully starting from a charge level less than or equal to 2 bars.
Outlander PHEV – Mitsubishi does not recommend leaving your car plugged in for a longer period of time than necessary.
While you’re not driving it, aim to keep the charge at around the 30% mark and leave it unplugged. You can then charge the car up to full just before you need to use it.
Your EV battery will be better off if the charge is maintained at about 30% of capacity, which is the best amount to keep the battery in optimal condition.
Your 12V battery on a hybrid or electric car will lose charge the same as it will on a regular car, so start your vehicle once a week and let it run for about 20 minutes. This will allow the battery to maintain charge during extended periods where it isn’t being driven.
Refer to website: https://www.mitsubishi-motors.co.uk/articles/hybrid-car-care-and-coronavirus
Leaf, e-NV200 – EVs should be put in Ready Mode to operate the charging system, doing this for 15 minutes once a week should keep the 12V battery topped up. If you do not have access to a home charger, running the car once a week should help the high-voltage traction battery to top up the 12V battery.
Refrain from using Telematics or Connected Services while the vehicle is parked up as this can cause an unnecessary drain on the 12V battery system.
For the high-voltage battery it is recommended that the state of charge is kept between 50% and 80%, and not to leave the vehicle plugged in once the high voltage battery has finished charging.
Do not operate the charging timer repeatedly while the charge connector is connected to the vehicle after the Li-ion battery charging is completed. Doing so may discharge the 12V battery.
Avoid exposing a vehicle to extreme ambient temperatures for extended periods to maximuse battery life. Owners should avoid storing a vehicle in temperatures below 23ºC for more than seven days.
Avoid leaving your vehicle for more than 14 days where the Li-ion battery available charge gauge reaches a zero or near zero (state of charge).
Park/store your vehicle in cool locations out of direct sunlight and away from heat sources.
Peugeot
e-208, e-2008 – Fully recharge the traction battery every three months. Follow the domestic charging procedure.
Before carrying out this charging operation, check that the accessory battery is not disconnected or discharged. If it is, refer to the corresponding section for information on reconnecting or recharging it.
iOn – To optimise the service life of the main battery, recharge it completely every two weeks.
For a complete charge, follow the normal charging procedure (domestic electricity supply) without interruption until it stops automatically (confirmed by the charging warning lamp going off in the instrument panel).
In addition, every three months, make sure that you charge the main battery fully starting from a charge level less than or equal to 2 bars.
Porsche
Plug-in hybrids – Porsche recommends to leave plug-in hybrid vehicles plugged into the car’s charger, which will also condition the 12V battery. Each hybrid charging unit will have a 3-pin connector for domestic plugs, which adds flexibility for those who wouldn’t normally charge at home. Porsche’s advice for owners who aren’t able to do this is to start the car once a week and leave it running for 15 minutes – Plug-in hybrids can be put into Sport mode to fire up the engine at standstill and also add charge to the hybrid battery pack.
For further advice, see Porsche’s official Twitter feed here: https://twitter.com/PorscheGB/status/1248130773502193664?s=20
Renault
All models – You can perform partial or full charges on the traction battery, with no particular restraints.
If the vehicle is not used for a period of time, such as during holidays, this will not discharge the traction battery to any noticeable extent.
Where possible, avoid charging and parking your vehicle in extreme temperature conditions (hot or cold) to keep a high traction battery performance.
ZE vehicles should be charged using a standard charge point to maintain the battery charge if not being used. The 12V battery runs off the traction battery, so this is especially advisable.
Do not use your electric vehicle to restart the 12V battery in another vehicle. The 12V electric power of an electric vehicle is not enough to perform such an operation and risks damaging the car.
SEAT
All models – While we’d generally advise customers not to trickle charge their vehicles, however these are certainly unusual times. Our customer helplines remain open, as well as the live chat feature on www.seat.co.uk, so in the first instance we’d suggest a customer contact SEAT customer services, or their local retailer, for guidance on their individual case.
A vehicle can be trickle charged but it’s important to note that our vehicles use lithium-ion batteries so if a customer wishes to utilise a smart charger then it must be compatible for this battery type, and it must not be rated more than 32A with a capacity of 250Ah.
Tesla
Model 3 – The most important way to preserve the battery is to LEAVE YOUR VEHICLE PLUGGED IN when you are not using it. This is particularly important if you are not planning to drive Model 3 for several weeks. When plugged in, Model 3 wakes up when needed to automatically maintain a charge level that maximises the lifetime of the battery.
NOTE: When left idle and unplugged, your vehicle periodically uses energy from the battery for system tests and recharging the 12V battery when necessary.
There is no advantage to waiting until the battery’s level is low before charging. In fact, the battery performs best when charged regularly.
NOTE: If you allow the battery to discharge to 0%, other components may become damaged or require replacement (for example, the 12V battery). In these cases, you are responsible for repair and/or transporting expenses. Discharge-related expenses are not covered by the warranty or under the Roadside Assistance policy.
The peak charging rate of the battery may decrease slightly after a large number of DC Fast Charging sessions, such as those at Superchargers. To ensure maximum driving range and battery safety, the battery charge rate is decreased when the battery is too cold, when the battery’s charge is nearly full, and when the battery conditions change with usage and age. These changes in the condition of the battery are driven by battery physics and may increase the total Supercharging duration by a few minutes over time.
All models – Never allow the battery to fully discharge. Even when your car is not being driven, its battery discharges very slowly to power the onboard electronics. The battery can discharge at a rate of approximately 1% per day, though the discharge rate may vary depending on environmental factors (such as cold weather), vehicle configuration, and your selected settings on the touchscreen.
Situations can arise in which you must leave your Tesla unplugged for an extended period of time (for example, at an airport when travelling). In these situations, keep the 1% in mind to ensure that you leave the battery with a sufficient charge level. For example, over a two week period (14 days), the battery may discharge by approximately 14%.
Discharging the battery to 0% may result in damage to vehicle components. To protect against a complete discharge, your Tesla enters a low-power consumption mode when the displayed charge level drops to approximately 0%. In this mode, the battery stops supporting the onboard electronics and auxiliary 12V battery. Once this low-power consumption mode is active, immediately plug in your Tesla to prevent a jump-start and 12V battery replacement.
NOTE: If the vehicle is unresponsive and will not unlock, open, or charge, then the 12V battery may have become discharged. In this situation, contact Tesla.
Toyota (and Lexus)
All hybrid models – maintain charge in both batteries by going through the normal start procedure: press the Start button with your foot on the brake until the ‘Ready’ light is illuminated on the dashboard. Earlier hybrid models may have key ignitions to start the car.
Leave the car in ‘Ready’ mode for about 60 minutes (no need to keep your foot on the brake) before switching it off again and repeat the process every couple of weeks.
Always adhere to the government’s advice regarding social distancing and Coronavirus (Covid-19) and please don’t leave your car unattended when it is switched on. While the car is in ‘Ready’ mode, you may hear and feel the internal combustion engine kick in, which is a normal part of the self-charging process.
It’s best to keep electrical items such as the radio turned off as these consume small amounts of power.
For 12V batteries specifically, if you have a suitable trickle charger, or a solar panel charger, and are confident using them, then these are a good option to keep the battery fully charged while the vehicle is stationary for a period of time. You might want to consider an intelligent trickle charger that will only charge the battery when it needs to.
e-Golf – All batteries deteriorate with age, depending on their service life and how they are used. To maintain the high-voltage battery in a good and reliable condition for as long as possible, it is important to know how to handle and care for the battery properly.
Frequently charging the high-voltage battery with a high charging power can lead to a permanent reduction in the charging capacity. Charge the high-voltage battery mainly with a low charging power, e.g. at a home charging station (wall box) or tested mains socket.
If the vehicle is parked for a long period with a discharged high-voltage battery, irreversible damage can be caused to the high-voltage battery.
Always charge the high-voltage battery without delay.
Self-discharge of the high-voltage battery, e.g. due to the vehicle standing for periods of several months, can lead to the high-voltage battery being damaged if ambient temperatures are high and the high-voltage battery has a low charge level.
Charging the vehicle for the first time or after it has not been used for a long time
If the high-voltage battery is new or has not been charged for a long time, the maximum charge of the high-voltage battery will probably not be reached until after several charging cycles. This is for technical reasons and does not represent a vehicle malfunction.
If the vehicle is not used for a long period, the high-voltage battery must be charged after four months at the latest.
If the charging cable is left connected after charging, the high-voltage battery will not be discharged by electrical consumers in the vehicle.
For other models see owner’s manuals available at: https://www.volkswagen.co.uk/owners/manuals
All models – In order to maintain the 12V starter battery in good condition, it is recommended that there is at least 15 minutes driving/week or that the battery is connected to a battery charger with automatic trickle charging. A starter battery that is kept fully charged has a maximum service life.
48V systems should never be connected to to external electrical equipment, nor should they be used to jump start other cars. 48V batteries should only be serviced and replaced by a workshop.
Plug-in hybrid models – Long-term storage of vehicles with hybrid batteries: To help minimise degradation of the hybrid battery if the vehicle is not driven for a prolonged period (longer than 1 month) the hybrid battery charge level should be kept at approximately 25% according to the gauge in the instrument panel.
Do as follows:
1. If the hybrid battery charge level is high, drive the vehicle until the charge level is approximately 25%. If the charge level is low, charge the battery until the level reaches approximately 25%.
2. If the vehicle is not driven for more than six months or the hybrid battery’s charge level is noticeably below the 25% mark, charge the battery to about 25% to help compensate for the natural battery dis-charge that occurs in long-term storage. Regularly check the charge level using the gauge in the instrument display.
NOTE: Store the vehicle in as cool a location as possible to minimise battery ageing during long-term storage. In the summer, park the vehicle indoors or in a shady location, whichever is cooler.
