Q1. We will apply for supporting member with plan to install CHAdeMO chargers. But details have not been decided yet. Can we get exemption from the annual membership dues?

Q2. We joined CHAdeMO Association during business year (fiscal year). Should we pay full amount of annual dues?

Q3. We are non-profit organization and will develop CHAdeMO charger. Can we get exemption from the annual membership dues?

Q4. We are non-profit organization. Can we become observer?

Q5. Isnít the battery deteriorated by quick charging?

Q6. Isnít the maximum output of 500V/100A of DC quick charger dangerous for general public to handle?

Q7. For the communication method, why CAN is adapted, not PLC?

Q8. It costs millions of yen to install one DC quick charger. Isnít it too costly for public infrastructure?

Q9. If we deploy AC quick charging system, we can have one vehicle AC inlet usable for both quick charging and normal charging?

Q10. If the future battery cost reduction leads to more batteries loaded on EVs, donít we have to think about higher-capacity chargers like 100kW or 200kW?

Q11. When several DC quick chargers are connected, doesnít the burden of power distribution lines and electric power systems increase?

Q12. Why does charging speed become slow when EV has larger stored electricity in its battery?





Q1. We will apply for supporting member with plan to install CHAdeMO chargers. But details have not been decided yet. Can we get exemption from the annual membership dues?

A1. Yes. But you should inform us after details have been decided.


Q2. We joined CHAdeMO Association during business year (fiscal year). Should we pay full amount of annual dues?

A2. If you joined in the first half (between 1 April and 30 September), you need to pay full amount of annual dues.
If you joined in the second half (between 1 October and 31 March), you need to pay a half amount of annual dues.


Q3. We are non-profit organization and will develop CHAdeMO charger. Can we get exemption from the annual membership dues?

A3. No. You should become a regular member to access CHAdeMO specification (CHAdeMO protocol).


Q4. We are non-profit organization. Can we become observer?

A4. Administrative body, public agency or non-profit organization can join the Association as observers after the approval of CHAdeMO association.
But observer can
- not access CHAdeMO specification (CHAdeMO protocol).
- participate infrastructure workshop (only in Japan at this stage).

If you need CHAdeMO specification, please apply for regular member.


Q5. Isnít the battery deteriorated by quick charging?

A5. CHAdeMo DC quick charger is controlled by ECU of EV, a microcomputer which controls the discharging and charging process of on-board battery, The ECU is continuously monitoring the SOC and temperature of the battery system, so that quick charging never deteriorates the battery.


Q6. Isnít the maximum output of 500V/100A of DC quick charger dangerous for general public to handle?

A6. The 500V/100A output is equivalent to the output of 10 air-conditioners. It goes beyond the output level of normal electronic products, thus to a dangerous extent.
This is the reason why CHAdeMo DC quick charger takes such an extreme safety measures; before the start of charging, the quick charger conducts double and triple check to make sure that the connection is perfectly done, and cables/connectors are completely insulated. It is after all those checking process is completed, and the safety is confirmed that the charging gets started.


Q7. For the communication method, why CAN is adapted, not PLC?

A7. Communications for quick charging requires high reliability because 500V/100A output of DC quick charger could lead to a fatal accident if one error occurs.
We consider that CAN has a highly reliable record of being used as a standard communication method for automotive electronic control systems for a long period of time. Its higher noise tolerance excels PLC as a communication method for ECU to control the charging process.


Q8. It costs millions of yen to install one DC quick charger. Isnít it too costly for public infrastructure?

A8. The installation cost of each DC quick charger is high. However, quick charger is not frequently used - only used for emergency case when the battery is running out away from home - and charging time is short , 5 to15 minutes per charging. These two characteristics, when it comes to building up charging infrastructure, will enable one DC quick charger to serve 100 to 200 EVs.
Even though the cost of a 200V charging stand, or outlet, is lower than a quick charger, a much larger number has to be installed to be used as public charging infrastructure. Also, the longer charging time means less convenience for EV users.
After all, we think that the combination of the normal chargers for daily use, being low-cost and can utilize the existing facilities, and a smaller number of quick chargers properly- located in public space, being used for emergency use, is the cost minimum design for the entire EV charging infrastructure.


Q9. If we deploy AC quick charging system, we can have one vehicle AC inlet usable for both quick charging and normal charging?

A9. Sharing one connector for normal and quick charging requires the adaptation of normal chargerís connecter/ cable to high-current and high-voltage, which makes them too thick, heavy and pricy to be used for daily use, so that they meet the safety regulations.
We think the optimal combination consists of making normal charger, which is used almost everyday, more useful, less costly, and making quick charger, which is less-frequently used, more speedy and safer, prioritizing safety to cost reduction.


Q10. If the future battery cost reduction leads to more batteries loaded on EVs, donít we have to think about higher-capacity chargers like 100kW or 200kW?

A10. Dealing with electricity exceeding 100kW in a safe manner is technically difficult. In addition, higher charging current or voltage will increase risk, cost, and difficulty of handling.
Battery performance will improve over time, but driving distance is decided by people`s life style thus does not increase proportionally. We believe hitting the right balance between the needs and costs determines the most appropriate output.


Q11. When several DC quick chargers are connected, doesnít the burden of power distribution lines and electric power systems increase?

A11. The maximum output of the current quick charger is 50kW, thus requires 6.6 kV high-voltage power supply at least. The capacity of distribution transformer, which supplies electricity to 6.6 kV high-voltage distribution line, is around 20MW. Therefore, switching on and off of several quick chargers doesnít affect the power quality.
Lower-capacity quick charger(20kW-30kW)is sometimes supplied with low-voltage (200V) electricity. In such case, a contract for capacity upgrade is necessary. Power utility will check whether the existing distribution line to make sure equipment such as pole-mounted transformers can withstand.


Q12. Why does charging speed become slow when EV has larger stored electricity in its battery?

A12. The charging speed is determined by a computer in EV, called ECU, based on the batteryís condition and temperature. DC quick charger supplies electricity according to the commands from ECU. To protect EVís battery, ECU slows the charging speed as the stored electricity increases.