To perhaps state the obvious — ChargePoint DC fast chargers are faster than Level 2 AC charging stations. They are also just as easy to use as AC chargers. Like any Level 2 charging station, simply tap your phone or card, plug in to charge and then go on your merry way. The best time to use a DC fast charging station is when you need a charge right away and you’re willing to pay a little more for the convenience — like when you're on a road trip or when your battery is low but you are pressed for time.
Check out these tips for a great DC fast charging experience.
Check your connector type
DC fast charging requires a different type of connector than the J1772 connector used for Level 2 AC charging. Leading fast charging standards are SAE Combo (CCS1 in the U.S. and CCS2 in Europe), CHAdeMO and Tesla, as well as GB/T in China. More and more EVs are equipped for DC fast charging these days, but be sure to take a look at your car's port before you try to plug in.
ChargePoint DC fast chargers can charge any vehicle, but CCS1 in North America and CCS2 in Europe connectors are best for the maximum amperage, which is becoming standard in new EVs. Tesla EVs require a CCS1 adapter for fast charging with ChargePoint.
Save fast charging for when you need it most
Fees are usually higher for DC fast charging than for Level 2 charging. Because they provide more power, DC fast charging stations are more expensive to install and operate. Station owners generally pass some of these costs on to drivers, so it really doesn’t add up to use fast charging every day.
Another reason not to overdo it on DC fast charging: A lot of power flows from a DC fast charger, and managing it puts extra strain on your battery. Using a DC charger all the time could reduce your battery’s efficiency and lifespan, so it’s best to use fast charging only when you need it. Keep in mind that drivers who don't have access to charging at home or work may rely more on DC fast charging.
Follow the 80% rule
Every EV battery follows what’s called a “charging curve” when charging. Charging starts slow while your vehicle monitors your battery’s charge level, the weather outside and other factors. Charging then climbs to peak speed for as long as possible and slows down again when your battery has reached about an 80% charge to prolong battery life. (Check out this post and this post to learn more about charging curves.)
With a DC fast charger, it’s best to unplug when your battery reaches about 80% charged. That’s when charging slows dramatically. In fact, it could take almost as long to charge the last 20% as it did to get to 80%. Unplugging when you reach that 80% threshold is not only more efficient for you, it’s also considerate to other EV drivers, helping ensure that as many people as possible can use available fast charging stations. Check the ChargePoint app to see how your charge is going and to know when to unplug.
Did you know? With the ChargePoint app, you can see the rate at which your car is charging in real time. Just click on Charging Activity in the main menu to see your current session.
AC vs. DC
Finally, if you’ve ever wondered why it’s called “DC fast charging,” the answer is simple. “DC” refers to “direct current,” the type of power that batteries use. Level 2 charging stations use “AC,” or “alternating current,” which you’ll find in typical household outlets. EVs have onboard chargers inside the car that convert AC power to DC for the battery. DC fast chargers convert AC power to DC within the charging station and deliver DC power directly to the battery, which is why they charge faster.
Products and reference designs of DC fast charging power module
Input current & voltage sense
Accurate and high speed sensory data of the various power busses in a DC charger is required to effectively control the power electronics and ensure operational safety. Isolated sensory techniques are routinely used due to the high voltages involved. Input current & voltage sense includes Isolated amplifiers、General-purpose op amps、Comparators、Precision op amps (Vos<1mV)、Series voltage references、Shunt voltage references, the Corresponding products are AMC1351、TLV9154、TLV1811、OPA2191、REF4132、LM4040
AC/DC power stage
The first power stage within a DC charging pile is an AC/DC stage. This stage preforms power factor correction and provides a high voltage DC rail to then be used by the next stage. Glue logic is used to connect the power DSP to the gate drivers in order to correctly set logic voltage levels, active high or low settings, and serve as a buffer for multiple GPIO outputs. AC/DC power stage includes Isolated gate drivers、Low-side drivers、PWM controllers、Isolated DC/DC converters & modules、Flyback controllers、SR & load share controllers、Half-bridge drivers、Power factor correction (PFC) controllers、Gallium nitride (GaN) ICs、Noninverting buffers & drivers、Digital isolators, the Corresponding products are UCC21551、UCC27624、UCC28C54、UCC12040、UCC28730、UCD7138、UCC27211A、UCC28180、LMG3410R070、SN74ALVC244、ISO7761
Bus current & voltage sense
Accurate and high speed sensory data of the various power busses in a DC charger is required to effectively control the power electronics and ensure operational safety. Isolated sensory techniques are routinely used due to the high voltages involved. Bus current & voltage sense includes Isolated amplifiers、Hall-effect current sensors、General-purpose op amps、Comparators、Precision op amps (Vos<1mV)、Series voltage references, the Corresponding products are AMC3330、TMCS1126、TLV9154、TLV1811、OPA2191、REF4132
DC/DC power stage
The DC/DC stage takes the high voltage DC from the AC/DC stage output and controls the voltage and current to work with the other power modules to deliver power to the electric vehicle. Glue logic is used to connect the power DSP to the gate drivers in order to correctly set logic voltage levels, active high or low settings, and serve as a buffer for multiple GPIO outputs. DC/DC power stage includes Isolated gate drivers、Low-side drivers、Half-bridge drivers、PWM controllers、Isolated DC/DC converters & modules、Flyback controllers、SR & load share controllers、Power factor correction (PFC) controllers、Noninverting buffers & drivers、Digital isolators, the Corresponding products are UCC23513、UCC27444、UCC27712、UCC28C55、UCC12040、UCC28730、UCD7138、UCC28070、SN74ALVC244、ISO6721
Output current & voltage sense
Accurate and high speed sensory data of the various power busses in a DC charger is required to effectively control the power electronics and ensure operational safety. Isolated sensory techniques are routinely used due to the high voltages involved. Output current & voltage sense includes Isolated amplifiers、General-purpose op amps、Comparators、Precision op amps (Vos<1mV)、Series voltage references、Shunt voltage references, the Corresponding products are AMC1200、TL082H、TLV1811、TLV2376、REF4132、LM4040
Relay control power stage
For safety purposes, the output of each power module contains a relay before connecting to the main DC output. The relay also enables protection for the system itself and the other connected systems by allowing a disconnect in the event of a fault. Relay control power stage includes Solenoid drivers、Brushed DC (BDC) motor drivers、Low-side switches, the Corresponding products are DRV103、DRV8701、ULN2003AI
Insulation monitor
For safety purposes, insulation monitoring allows an accurate symmetrical and asymmetrical insulation leakage detection mechanism and an isolation resistance detection mechanism. Insulation monitor includes Linear & low-dropout (LDO) regulators、Series voltage references、Solid-state relays、General-purpose op amps、Isolated amplifiers, the Corresponding products are TLV709、REF4132、TPSI2140-Q1、OPA2992、AMC3330
Residual current monitor
Residual current monitor (RCM) detects fault current levels defined by IEC62752/IEC62955. Example requirements: 6mA DC & 30mA RMS AC ground fault detection for single and polyphase; response time in less than 40ms. Residual current monitor includes General-purpose op amps、Comparators、Precision op amps (Vos<1mV)、Brushed DC (BDC) motor drivers、D-type flip-flops, the Corresponding products are TLV9154、TLV1811、OPA2182、DRV8871、SN74HC74
Analog front end
External ADC is optional. Integrated ADC in MCU is common practice. To ensure tight control loops on the ACDC and DCDC stages, the DSP requires high accuracy data from the various analog sensors across the system. Dedicated analog filters and amplifiers help reduce noise and properly scale signals regardless of the ADC used. Analog front end includes General-purpose op amps、Precision op amps (Vos<1mV)、Series voltage references、Shunt voltage references、Precision ADCs、Precision DACs (≤10 MSPS), the Corresponding products are OPA2990、OPA2191、REF4132、LM4040、ADS7054、DAC60504
Power digital processing
Both main power stages in an EVSE are controlled by a DSP. Using a DSP-based solution power can be more efficiently converted from the grid, and power factor correction can be much more effective. Dedicated DSPs for the application will have sufficient MIPS or accelerators, as well as performance for a communications layer. Each power module is likely to have a dedicated DSP. RTC is employed when precise timekeeping is required to perform operations or measure time passed. Power digital processing includes C2000 real-time microcontrollers、Arm Cortex-M0+ MCUs、Arm Cortex-M4 MCUs、MSP430 microcontrollers、Noninverting buffers & drivers、Clock buffers、Real-time clocks (RTCs) & timers, the Corresponding products are TMS320F2800157、MSPM0G3507、TM4C1294KCPDT、MSP430G2553、SN74LVC2G34、LMK1C1103、NA555
Plug lock driver
For safety purposes, the plug lock secures the cable against unintentional disconnection while charging is active. Plug lock driver includes Brushed DC (BDC) motor drivers, the Corresponding products are DRV8871、DRV8220
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