How many times have you done fast charging of your LEAF? Not yet tried it? Or Are you afraid to fast charge your LEAF? If you are a LEAF owner you would probably have answers to these questions. Whatever the creed you are in, fast charging or non-fast charging, it will be helpful for you to understand the underlying mechanism and the real facts in order to drive your LEAF that extra mile.
ome LEAF owners prefer to use fast charging. You don’t have to wait quarter a day to juice up your LEAF as in normal charging. It really helps to travel you farther. At present the fast charging prices in Sri Lanka is at an affordable range for the sake of many competitive service providers. Some LEAF owners refrain from fast charging due to various reasons. It affects battery life. You can save more money by using normal charging. Normal charging gives you more safety. So let’s go deep and see what are the facts and myths.
In the normal charging, the outside charger supplies 230V AC voltage to the LEAF’s charging port. The 230VAC to 400VDC conversion to charge the batteries is done in the onboard charger inside the vehicle. Hence the capacity of the onboard charger is limited to 3.6kW or 6.6kW to reduce the weight and cooling requirement. In the fast charging, the outside charger does the power conversion from AC to DC and a DC current at battery voltage is connected to the LEAF’s fast charging port. Onboard charger is not connected in fast charging but a large number of safety features has been implemented in the vehicle. Since the bulky AC to DC converter is in the outside charger in fast charging, very high power requirements could be achieved with faster charging rate and short charging time.
The fast charging standard in Nissan LEAF is called CHAdeMo. It is commonly accepted standard in Asian region. Nissan, Mitsubishi and KIA directly use the CHAdeMO standard for the fast charging and TESLA also supports CHAdeMO standard with the use of a converter. You could easily identify the CHAdeMO port in LEAF which is located alongside your normal charging port. You could only fast charge your LEAF with a charger compatible with the CHAdeMO standard. In the CHAdeMO standard many safety features have been implemented in both vehicle and the charging station. For an example the limits of the required current are defined for the fast charger and if this limit is exceeded by the charger, the vehicle will immediately stops the charging. So if you are worried about the safety in fast charging, let’s say it is as safe as the normal charging.
The fast charging in the context of LEAF varies from about 10kW to 50kW. That means the charging current varies from 25A to 125A and charging time from 75 minutes to 20 minutes. When the current is flowing through the battery pack in charging or discharging, the cells get heated up due to the inherent internal resistance. That is the reason for the increase of battery temperature while you drive fast. In fast charging the battery temperature also gets increased due to the high current flow. So if you are going to fast charge immediately after a highway drive or going to drive very fast immediately after a fast charge, keep your eye on the battery temperature bar. Exposing the batteries to high temperatures constantly will reduce the battery health. It is a good practice to drive economically after a fast charge and keep your LEAF a while before fast charging if she’s too hot. That’s a fact you cannot avoid.
In normal charging you can charge your LEAF up to 100% and you may have noticed the last 20% usually takes more time to charge. If you have used eStation charger, you could see the charging current gradually reduces after the 80% level. This happens due to the charging cycle of the Li-ion battery and the cell balancing of the Battery Management System (BMS). The cell balancing is required in the last states of the charging in order to prevent cells from overcharging. When you are using fast charging, it will be healthier for LEAF if you charge only up to 80%. The cell balancing may not be properly obtained at high charging rate and may affect the battery health if you are frequently fast charging more than 80%. So keep in mind the 80% limit in fast charging you LEAF.
The most important fact is fast charging is not recommended by Nissan as the main charging medium for LEAF. That means even it saves lot of time and hazel, do not go for only fast charging instead of normal charging. The fast charging is given as an option for convenience which you could use if you are travelling longer distance than LEAF’s range. As a LEAF owner you don’t need see fast charging as a beast waiting to destroy your beloved LEAF and don’t always get it as a detour which saves your time. Be aware of the pros and cons and use it for the quality of ride with your ever loving LEAF.
chargeNET Pvt. Ltd.