Gurugram
+918076792323

'frequent charging'

Items tagged with 'frequent charging'

product image
Amaron Quanta 12v 42Ah Battery

The Amaron Quanta 42Ah (Ampere-hour) battery is a high-performance, maintenance-free lead-acid battery designed for use in UPS systems, inverters, and solar energy storage applications. It provides reliable power backup for a range of devices, especially in environments where power stability and uninterrupted performance are crucial. Key Features of Amaron Quanta 42Ah Battery: Capacity: 42Ah (Ampere-hour) – This means the battery can provide 42 amps of current for one hour, or a proportionally smaller amount of current over a longer period of time, depending on the load. Technology: Maintenance-Free: The Amaron Quanta series batteries are sealed lead-acid batteries (SLA) that do not require frequent maintenance or water refilling, making them very convenient and hassle-free. High Performance: Designed for high efficiency, the Amaron Quanta 42Ah battery offers good charge retention, ensuring long-lasting backup for your UPS or inverter. Deep Cycle Battery: This is a deep-cycle battery, meaning it is designed to handle deeper discharges compared to regular car batteries. It is well-suited for applications where the battery may be discharged and recharged frequently. Durability: Long Shelf Life: Amaron Quanta batteries have a good shelf life and can perform well over extended periods when properly stored. High-Temperature Tolerance: They are built to withstand a wide range of temperatures, making them suitable for varying environmental conditions. Design: Compact and Reliable: The battery is designed to be compact, reliable, and easy to install, especially in environments where space is a concern. Vibration Resistant: The battery is engineered to resist damage from vibration, ensuring its durability in various settings. Safety Features: Flame-Retardant Materials: The Amaron Quanta 42Ah battery uses flame-retardant materials to ensure safety in case of battery malfunction. Leak-Proof: Being a sealed battery, it minimizes the risk of acid leakage, which adds an extra layer of safety. Application Areas: UPS Systems: Provides backup power to computers, servers, and networking equipment. Inverter Systems: Used in residential and small commercial applications to ensure uninterrupted power during outages. Solar Energy Storage: Can be used as part of a solar energy storage system to store excess energy generated during the day for use at night. Warranty: The Amaron Quanta batteries often come with a 2-year warranty, depending on the region and purchase conditions. It is recommended to check with the seller or manufacturer for specific warranty details. General Specifications: Voltage: 12V (standard for most UPS and inverter batteries). Capacity: 42Ah. Type: Sealed Lead-Acid (SLA) or AGM (Absorbent Glass Mat). Charging Voltage: Typically around 14.4 to 15.0V for 12V batteries. Nominal Voltage: 12V. Dimensions: Typically around length: 200mm, width: 165mm, height: 175mm (varies slightly depending on specific model). Weight: Approximately 12-14 kg. Maintenance Tips for the Amaron Quanta 42Ah Battery: Regular Charging: Always ensure that the battery is fully charged and avoid discharging it completely to extend its lifespan. Storage: If you’re storing the battery for an extended period, make sure to store it in a cool, dry place and check the charge level periodically. Clean the Terminals: Ensure the terminals are clean and free of corrosion. Clean the terminals with a mixture of baking soda and water if needed. Avoid Overcharging: Always use a compatible charger to avoid overcharging the battery, which could damage it. Check for Leakage: While the battery is sealed, it's a good idea to check for any leaks, especially if the battery has been in use for a long time or is showing signs of wear. Battery Testing: To check the health of the Amaron Quanta 42Ah battery, you can follow these steps: Voltage Check: Use a voltmeter to check the voltage. A fully charged 12V battery should show between 12.6V to 12.8V. Load Test: Under load, if the voltage drops rapidly below 10.5V for a 12V battery, it may be a sign of degradation. Capacity Test: If your application requires it, you can perform a discharge test to check the battery's capacity. This involves discharging the battery with a known load and measuring how long it takes for the voltage to drop below a certain threshold. Conclusion: The Amaron Quanta 42Ah battery is a reliable and durable option for providing backup power in various applications, including UPS systems, inverters, and solar power storage. It offers maintenance-free operation, a long service life, and excellent temperature tolerance. By regularly maintaining and testing the battery, you can ensure that it continues to perform effectively over time.

Send Message
product image
Luminous Ups

The Luminous LD30KH-PRO is a high-performance Inverter designed to provide reliable backup power for homes, offices, and small commercial setups. It is a part of Luminous' Pure Sine Wave Inverter series, offering high efficiency and stable power supply to sensitive equipment like computers, refrigerators, air conditioners, and other appliances. Here are the key features and specifications of the Luminous LD30KH-PRO: Key Features: Power Capacity: 30 kVA (Kilovolt-Ampere) – It is designed to support large power loads, making it suitable for medium to large residential, commercial, or industrial applications. Pure Sine Wave Output: Provides clean and stable output voltage, ensuring that sensitive equipment (like computers, air conditioners, and medical equipment) operates without issues, such as noise or voltage fluctuations. High Efficiency: The inverter operates with high efficiency, which reduces power loss and ensures that more of the battery's energy is used to power connected appliances. Advanced Microprocessor Technology: The inverter uses a microprocessor-based design to ensure high performance, protection, and reliability. It optimizes charging and discharging cycles, as well as load management. User-Friendly LCD Display: It comes with an intuitive LCD display that shows important information such as battery status, power usage, input and output voltage, and fault conditions. This helps users easily monitor and manage the system. Wide Input Voltage Range: The inverter operates with a wide input voltage range, which helps it perform well under varying input conditions. This feature helps protect connected equipment from power surges and fluctuations. Multiple Protection Mechanisms: Built-in protection features include overload protection, short-circuit protection, deep discharge protection, and battery reverse polarity protection, which ensures the safety of the connected equipment. Battery Compatibility: The Luminous LD30KH-PRO is compatible with both lead-acid and lithium-ion batteries, giving users flexibility depending on their preferences for battery technology. Smart Battery Management: The inverter comes with intelligent battery management to optimize battery performance, extending their lifespan and ensuring safe charging and discharging cycles. Compact and Reliable Design: Designed with a compact form factor and a durable build, the inverter is ideal for both indoor and outdoor installations and can be used for both backup power and off-grid applications. Applications: Residential Homes – For providing backup power for large appliances like air conditioners, refrigerators, lighting, and electronics. Small and Medium Businesses – For ensuring uninterrupted power supply to computers, servers, and other essential equipment. Commercial Use – Ideal for large offices, small industries, and workshops. Rural/Off-Grid Areas – Can be used in places with frequent power outages or no access to the grid, providing a reliable power solution. Specifications Summary: Rated Capacity: 30 kVA Output Type: Pure Sine Wave Input Voltage: 120V – 300V (depending on model) Charging Current: Adjustable (depends on load) Display: LCD with detailed status updates Battery Compatibility: Compatible with lead-acid and lithium-ion batteries

Send Message
product image
Amaron Tubular Battery

Amaron is a well-known brand, and they manufacture various types of batteries, including tubular batteries. These batteries are primarily used for inverter applications (backup power for homes and businesses) and for solar energy systems. Key features of Amaron Tubular Batteries: Long Life: Tubular batteries are known for their long service life, and Amaron's version is no different. The tubular plates offer better performance and longer discharge cycles. Durability: Amaron batteries are designed to handle harsh conditions and provide consistent power over extended periods. Deep Discharge: Tubular batteries are ideal for deep discharge applications, which means they can be used for long durations without damaging the battery. Low Maintenance: Although they are flooded lead-acid batteries, Amaron batteries generally require less maintenance compared to traditional batteries. Fast Charging: They have the ability to charge faster compared to flat plate batteries, making them a good choice for areas with frequent power cuts. Amaron offers a variety of options in this category, depending on your energy needs and system configuration. The exact specifications (capacity, voltage, etc.) would depend on the model you are considering.

Send Message
product image
Amaron Quanta 12V 18Ah Battery

The Amaron Quanta 12V 18Ah is a type of sealed lead-acid (SLA) battery, commonly used for backup power applications, such as in UPS systems, inverters, and other critical power supply systems. Here's a detailed breakdown of its specifications and features: 1. General Overview Brand: Amaron Quanta Battery Type: Sealed Lead-Acid (SLA) Battery Voltage: 12 Volts (V) Capacity: 18 Ampere-Hours (Ah) 2. Key Features Longer Battery Life: Amaron Quanta batteries are designed for long-lasting performance and high reliability. They typically offer a good lifespan, especially in applications with a low depth of discharge (DOD). Maintenance-Free: The battery is sealed, so it doesn’t require regular maintenance (e.g., adding water). Vibration Resistance: These batteries are designed to withstand vibrations, making them ideal for use in environments like telecoms, solar power, and UPS systems. Wide Operating Temperature: They can operate in a wide range of temperatures, typically from 0°C to 40°C, making them versatile for use in different climates. 3. Technical Specifications Voltage: 12V (Nominal) Capacity: 18Ah (Ampere-Hours) Dimensions: Length: 181 mm Width: 77 mm Height: 167 mm Weight: Around 5.2 to 5.5 kg (varies slightly based on exact model) Charge Voltage: 14.4V to 15.0V (during charging) Discharge Voltage: Typically 10.5V to 11.0V for complete discharge Self-discharge: Less than 3% per month at 25°C 4. Applications UPS Systems: The 12V 18Ah battery is widely used in smaller uninterruptible power supplies (UPS) for providing backup power to sensitive electronics. Inverters: It can also be used in small-scale inverters to provide backup power to homes or offices. Telecommunications: In telecom applications, these batteries can be used for backup power to critical network equipment. Solar Energy Storage: Sometimes used in small-scale solar energy systems for storing energy for use during off-sunlight hours. 5. Battery Design Features Valve Regulated Lead-Acid (VRLA): The Amaron Quanta battery uses VRLA technology, which means the battery is sealed and uses a valve to release gas in case of overpressure. Deep Cycle: Designed for regular deep discharge cycles, making it suitable for power backup applications where batteries frequently discharge. Absorbent Glass Mat (AGM): Some models use AGM technology, where the electrolyte is absorbed in a fiberglass mat, allowing the battery to be spill-proof and leak-proof. 6. Charge/Discharge Characteristics Charging: Amaron Quanta batteries typically use a constant voltage charge, with a float charge voltage of around 13.5V to 13.8V. Discharge: The battery can typically discharge down to around 10.5V under load, but frequent deep discharges can reduce the battery's overall lifespan. 7. Advantages Longer Service Life: Typically offers a long life when maintained and used properly, making it a cost-effective option for long-term use. Reliable Performance: Known for reliability in maintaining charge over time, especially in demanding environments. Environmentally Friendly: Sealed and maintenance-free design minimizes risks associated with acid leakage and spills. 8. Maintenance Maintenance-Free Design: As mentioned, the battery is sealed, so it doesn't require regular maintenance like adding distilled water. However, regular inspection for corrosion on terminals and proper charge maintenance is recommended. Charging Recommendations: Always charge the battery in accordance with the manufacturer’s recommendations. Overcharging or undercharging can significantly reduce the battery’s lifespan. 9. Warranty Amaron Quanta batteries often come with a warranty that covers defects in material or workmanship, which typically lasts for 1 to 2 years depending on the seller and country-specific terms. 10. Compatibility Compatible Devices: The Amaron Quanta 12V 18Ah battery is commonly used in small UPS systems, solar power applications, and other critical systems where consistent backup power is required. Charging Systems: Can be used with most standard 12V chargers designed for SLA or AGM batteries. Conclusion The Amaron Quanta 12V 18Ah battery is an ideal solution for users looking for a reliable, low-maintenance, and efficient power backup option in smaller systems. It is widely used in UPS systems, inverters, and telecommunications applications where it can provide critical backup power when needed.

Send Message
product image
All Types Of Ups & Batteries Repair And Maintenance Of Ups

Repair and maintenance of UPS (Uninterruptible Power Supply) systems and batteries are crucial for ensuring their reliability and longevity. Below is a comprehensive overview of the types of UPS systems, batteries, and the associated repair and maintenance practices. Types of UPS Systems Offline/Standby UPS: Description: Provides basic protection; switches to battery during a power outage. Maintenance: Regular battery checks and replacement every 3-5 years. Line-Interactive UPS: Description: Offers voltage regulation and battery backup; ideal for environments with frequent voltage fluctuations. Maintenance: Inspect and test the battery and inverter regularly; check for dust accumulation. Online Double-Conversion UPS: Description: Provides continuous power and isolates equipment from power issues. Maintenance: More complex; requires regular inspection of internal components, battery health checks, and firmware updates. Modular UPS: Description: Scalable systems that allow for adding or removing modules based on power needs. Maintenance: Regular checks on each module, ensuring proper connections and functionality. Types of Batteries Used in UPS Lead-Acid Batteries: Types: Sealed Lead Acid (SLA), Absorbent Glass Mat (AGM), Gel. Maintenance: Regularly check electrolyte levels (for non-sealed types), clean terminals, and test for capacity. Lithium-Ion Batteries: Description: Increasingly used due to longer life and lighter weight. Maintenance: Monitor battery management systems (BMS) for health and performance; check for firmware updates. Nickel-Cadmium (NiCd) Batteries: Description: Used in specific applications; known for durability. Maintenance: Regularly test for capacity and perform equalization charging. Repair and Maintenance Practices 1. Routine Inspections Visual Checks: Inspect for physical damage, corrosion, or loose connections. Environmental Conditions: Ensure the UPS and batteries are in a suitable environment (temperature, humidity). 2. Battery Maintenance Testing: Conduct regular load tests and capacity tests to assess battery health. Cleaning: Clean terminals and connections to prevent corrosion. Replacement: Replace batteries as per manufacturer recommendations (typically every 3-5 years for lead-acid). 3. UPS Maintenance Firmware Updates: Keep the UPS firmware updated for optimal performance. Component Checks: Inspect capacitors, fans, and other internal components for wear and tear. Cooling System: Ensure that cooling fans are operational and that vents are not blocked. 4. Emergency Procedures Testing: Regularly test the UPS under load conditions to ensure it functions correctly during an outage. Documentation: Maintain records of all maintenance activities, repairs, and battery replacements. 5. Professional Servicing Scheduled Maintenance: Engage professional services for comprehensive inspections and repairs, especially for complex systems like online UPS. Emergency Repairs: Have a plan in place for rapid response to UPS failures, including access to spare parts. Conclusion Regular maintenance and timely repairs of UPS systems and batteries are essential for ensuring uninterrupted power supply and protecting sensitive equipment. By following a structured maintenance schedule and engaging professional services when necessary, you can significantly extend the lifespan and reliability of your UPS systems and batteries. For specific service providers or detailed maintenance plans, consider reaching out to local UPS service companies or manufacturers for tailored solutions.

Send Message
product image
Battery

The Amaron Quanta 12V 160Ah SMF VRLA Battery (12AL160) is a premium sealed maintenance-free lead-acid (SMF) battery that is primarily used in applications requiring reliable and long-lasting power backup. This battery is designed for both residential and industrial use, offering a robust power supply for inverters, UPS systems, and other equipment that require stable power during outages. Here’s a detailed breakdown of its features, specifications, and applications: Key Features: Battery Type: SMF (Sealed Maintenance-Free) VRLA (Valve-Regulated Lead Acid) battery. This type of battery does not require regular water refilling, making it low-maintenance. The VRLA technology helps regulate the gas pressure inside the battery, preventing acid leakage and reducing the need for manual maintenance. Capacity: 160 Ah (Ampere-Hours), suitable for medium to high power backup applications. Provides reliable power for inverter systems and UPS (Uninterruptible Power Supply) for homes, offices, and small to medium commercial setups. Voltage: 12V – Ideal for most inverter systems, particularly those used in residential and commercial settings. Design and Construction: Sealed Design: The SMF design makes the battery spill-proof, which ensures safety even in the event of accidents or mishandling. Robust construction: The high-quality components used in the battery provide resistance to high temperatures, deep discharges, and vibration. Maintenance-Free Operation: Maintenance-Free: No need for water topping, which saves time and effort in the long run. The battery is sealed, and the use of VRLA technology ensures no need for periodic maintenance, unlike traditional flooded lead-acid batteries. Deep-Cycle Capability: Deep Discharge Tolerance: This battery can discharge deeply without compromising its lifespan, making it a good choice for areas that face frequent power outages. It is designed for applications requiring frequent cycling (discharge/recharge) without damaging the internal plates. Durability: Long life: It offers a longer life span compared to regular flat-plate lead-acid batteries. The high-performance design ensures it can withstand extreme conditions like temperature fluctuations and high heat. Safety Features: Valve Regulated: The battery is equipped with a valve to control internal gas pressure, ensuring that no dangerous gas buildup occurs. Spill-Proof: Even in the event of damage, the battery will not leak electrolyte, making it safe to install in a variety of locations. Quick Charge & High Efficiency: The Amaron Quanta 12V 160Ah battery features quick charging capabilities, making it ideal for use in environments where fast recovery is important.

Send Message
product image
Battery

The Amaron 200Ah Current Tall Tubular Inverter Battery (AR200TT54) is a popular choice for home and small office power backup solutions. It is known for its long-lasting performance and is designed to support high power demands while offering reliable service for inverters. Here\'s a detailed breakdown of the features and specifications of this battery: Key Features: Battery Type: Tubular Lead Acid Battery – Known for better deep-cycle performance and durability as compared to flat-plate batteries. It is especially suited for areas with long and frequent power outages. Capacity: 200 Ah (Ampere-Hours) – This indicates the total charge the battery can hold, with 200 Ah being suitable for larger inverters or longer power backup requirements. Design: Tall Tubular Design – The tubular design enhances performance and life span as it offers better heat dissipation and reduces the chances of plate corrosion. Technology: Amaron\'s proprietary technology – Utilizes advanced battery design and manufacturing processes that provide greater resistance to overcharging, longer life, and higher efficiency. Maintenance: Low maintenance – The battery comes with an advanced grid technology and corrosion-resistant components, which minimizes the need for constant maintenance. Long Life: Longer battery life – The tubular design and advanced technology help extend the life of the battery compared to other types of lead-acid batteries, making it a reliable long-term investment. High Durability: Durable in high temperatures – It performs well in high-temperature conditions, making it suitable for regions with hot climates. Deep Discharge Recovery: Deep discharge tolerance – This battery can tolerate deep discharges and can recover from them effectively, making it more reliable when the power goes out for extended periods. Warranty: Typically comes with a 2-year warranty (may vary depending on the dealer or region), which ensures that the battery is protected against manufacturing defects. Performance Considerations: Backup Time: The backup time depends on the load connected to the inverter. A 200Ah battery typically supports moderate to heavy loads for up to 6-8 hours depending on inverter efficiency and power usage. Charging Time: Generally, a fully discharged 200Ah battery will take 8–12 hours to charge completely, depending on the charging system’s capacity. Applications: Home UPS Systems: Ideal for homes with moderate to heavy power usage. Inverters: Works well with most domestic and industrial inverters. Solar Systems: Can be used for off-grid and hybrid solar setups. Small Offices/Commercial Use: Suitable for locations that require a stable and reliable power backup. Pros: Long-lasting: The tubular design offers superior longevity compared to other types of batteries. Higher Charge Retention: Better charge retention ensures less frequent charging. Corrosion Resistance: Advanced technology ensures that the plates are protected from corrosion, which can extend the battery life. Cons: Weight: As a high-capacity lead-acid battery, it is heavy and might require more effort during installation. Space Requirements: It may require a bit more space compared to flat plate batteries due to its larger size. Conclusion: The Amaron AR200TT54 200Ah inverter battery is an excellent choice for those who need a high-capacity, durable, and low-maintenance backup solution. Whether you are using it for residential, commercial, or solar power applications, it provides long-term performance and reliability in all kinds of power outage scenarios.

Send Message
product image
2kva ups repair

Vertiv (formerly Emerson Network Power) is a leading provider of uninterruptible power supply (UPS) systems, power management, and thermal management solutions. Vertiv\'s UPS systems, including models with 2kVA capacity, are widely used in homes, offices, and small businesses to provide reliable power backup during grid power failures or fluctuations. When a Vertiv 2kVA UPS encounters issues, it may require repair, either due to a malfunctioning component or wear-and-tear over time. Here’s an overview of common problems, repair procedures, and troubleshooting steps for Vertiv 2kVA UPS repair: Common Problems in Vertiv 2kVA UPS UPS Not Turning On Possible Causes: Faulty battery or dead battery Blown fuse or circuit breaker Power supply input issue (fuse or switch) Repair Action: Check and replace the battery if necessary. Inspect the fuse or circuit breaker and replace if blown. Verify the input power connections. Frequent Switching to Battery Mode Possible Causes: Input power fluctuations or poor power quality Battery failure or degraded battery capacity UPS in bypass mode due to an internal fault Repair Action: Test the incoming voltage using a multimeter to ensure it’s within the UPS input range. Check the battery voltage; if it\'s low, consider replacing the battery. Check if the UPS is in bypass mode and reset it if necessary. UPS Not Charging the Battery Possible Causes: Faulty charger circuit Bad battery connections or corroded terminals Defective charging board Repair Action: Inspect battery terminals for corrosion and clean them. Test the charging voltage and check for proper charging circuit operation. If the charger board is defective, it may need to be replaced. Overheating and Shutdown Possible Causes: Overloaded UPS (too many devices connected) Poor ventilation or blocked air vents Faulty cooling fan Repair Action: Disconnect unnecessary devices and reduce the load. Ensure the UPS has proper ventilation and airflow around it. Check the fan for functionality; replace if faulty. UPS Producing Beeping Sound Possible Causes: Low battery Overload condition Internal fault or failure of components Repair Action: Replace or recharge the battery if it’s low. Disconnect some load if the UPS is overloaded. If the beeping persists, perform a deeper diagnostic of internal components (inverter, rectifier, etc.). Output Voltage Issues (Distorted or Incorrect Voltage) Possible Causes: Faulty inverter or rectifier circuit Problem with the output transformer Faulty output relay or PCB Repair Action: Measure the output voltage and compare it with the rated output. Inspect the inverter and rectifier circuits for any faults or blown components. Check the PCB for signs of damage or burnt components.

Send Message
product image
4 kva ups

The Luminous Cruze+ 4kVA is a high-performance online UPS that provides uninterrupted power for residential, commercial, and IT applications. Being an online UPS, it offers continuous, stable power with zero transfer time, making it ideal for sensitive equipment such as computers, servers, medical devices, and industrial systems. Key Features of Luminous Cruze+ 4kVA UPS Online Double-Conversion Technology: The Cruze+ 4kVA uses true online double-conversion technology, which ensures that your devices get clean, continuous, and regulated power without interruptions. In case of any fluctuations in the input voltage, the UPS immediately corrects it and ensures stable output voltage. Pure Sine Wave Output: The UPS provides pure sine wave output, which is ideal for sensitive devices, as it ensures minimal distortion and avoids any damage to electronic equipment, unlike square wave UPS systems that can harm certain types of equipment. High Efficiency: With a high conversion efficiency, the Cruze+ 4kVA reduces energy consumption and operational costs. This makes it not only a reliable backup solution but also energy-efficient. Wide Input Voltage Range: The Cruze+ UPS is designed to handle a wide input voltage range, which ensures that the system performs well even in areas with frequent voltage fluctuations, thereby reducing wear and tear on both the UPS and connected devices. Long Battery Life: Equipped with advanced battery management features, this UPS helps in optimizing the battery life, offering extended service periods even with frequent use. LCD/LED Display: The LCD display shows real-time status of the UPS, including input/output voltage, battery charge status, load percentage, and any faults. The LED indicators make it easier to monitor and understand the operational status at a glance. Battery Charging: The Cruze+ 4kVA UPS can handle multiple battery types, including lead-acid and VRLA batteries. It is equipped with an intelligent charging system that ensures batteries are charged efficiently without overcharging. Overload and Short Circuit Protection: Provides overload protection and short-circuit protection, ensuring that the system is safe from potential damage during power surges or faults. Battery Bank Options: The Cruze+ 4kVA is typically paired with a separate battery bank that provides the backup power. This can include Exide tubular batteries or Luminous batteries for optimal performance. Applications Residential: For powering sensitive equipment like computers, medical devices, and other electronics. Commercial: Protects servers, networking equipment, and office devices. Industrial: Suitable for critical industrial machines, automation systems, and control panels. Technical Specifications Capacity: 4kVA (4000 VA) Input Voltage: 140V - 300V (Wide input voltage range) Output Voltage: 220V / 230V (Pure sine wave) Output Frequency: 50 Hz ± 0.2 Hz Battery Charging Current: Adjustable (Typically 5-10A) Battery Type: Compatible with VRLA, Lead-Acid, and Tubular Batteries Backup Time: Depends on the battery capacity (typically, it can provide backup for 2-4 hours depending on the load and battery bank size). Dimensions (LxWxH): 465mm x 310mm x 115mm Weight: Around 15-18 kg (excluding battery) Warranty: 2 years on the UPS (can vary based on the model or region)

Send Message

Still searching for
frequent charging?