battery

-# Optical Coupler DAT

-

-# Lead-acid-battery-dat

-

-

-

-Batteries store the energy produced by your solar panels for later use.

-

-## Types:

-

-### General Lead-Acid Batteries:

-

-Common in automotive applications. They are relatively inexpensive and the technology is mature. However, they are heavy, have a shorter lifespan (approx. 3 years), require maintenance, and are not suitable for frequent deep discharge (recommended depth of discharge is ~20%).

-

-### Deep Cycle Lead-Acid Batteries:

-

-Designed for deep discharge (up to 80% or more) without significantly affecting lifespan. They have thicker plates and durable materials, making them well-suited for solar power systems, electric vehicles, and campers requiring continuous, stable power.

-

-

-**Capacity:** Measured in Amp-hours (Ah). A 12V 100Ah battery stores 12V * 100Ah = 1200 Watt-hours (Wh) of energy.

-

-

-

-

-## lead-acid-battery-dat

-

-- LAB: Lead-Acid Battery

-- 蓄电池 (xù diàn chí) is the Chinese term for "rechargeable battery." It is a type of electrical battery that can be recharged multiple times. It is commonly used in various electronic devices such as mobile phones, laptops, electric vehicles, and many other portable devices.

-

-- Here are some links where you can find more information about 蓄电池:

-

-- Wikipedia: Rechargeable Battery - https://zh.wikipedia.org/wiki/%E8%93%84%E7%94%B5%E6%B1%A0

-- China Battery Industry Association - http://www.cbia.com.cn/

-- Battery University: Rechargeable Batteries - https://batteryuniversity.com/learn/article/types_of_rechargeable_batteries

-

-## voltage

-

-- 12V == [[solar-power-dat]]

-- 72V == [[motor-dat]]

-

-## LAB Example

-

-

-

-* **Brand:** ANJING

-* **Type:** Sealed Rechargeable Battery (Likely SLA/VRLA) Sealed Lead-Acid (a specific type, but often used generally)

-* **Nominal Voltage:** 12V

-* **Capacity:** 2.6Ah (Rated at 20-hour discharge rate - 12V 2.6Ah/20hr)

- * This implies a discharge current of 0.13A (2.6Ah / 20h) for 20 hours.

-* **Charging Method:** Constant Voltage Charge

- * **Standby Use (Float):** 13.50V - 13.80V

- * **Cycle Use:** 14.40V - 15.00V

- * **Initial Charging Current:** Less than 0.78A (0.3C)

-* **Chemistry:** Lead-acid (Pb symbol present)

-* **Markings:**

- * Recycling symbol

- * Do not dispose symbol (crossed-out bin)

-

-As noted on the battery (12V2.6Ah/20hr), this specific 2.6Ah rating was determined using a 20-hour discharge period. This means it was likely discharged at a current of 0.13A (2.6Ah / 20h = 0.13A) for 20 hours.

-

-

-### Estimated Runtime Calculation

-

-This calculation estimates how long the ANJING 12V 2.6Ah battery can power a 5V 1A load using a DC-DC converter.

-

-**1. Calculate Load Power:**

- - Load Voltage (V_load) = 5V

- - Load Current (I_load) = 1A

- - Load Power (P_load) = V_load × I_load = 5V × 1A = 5 Watts

-

-**2. Account for DC-DC Converter Efficiency:**

- - Assume a typical converter efficiency (η) = 85% (or 0.85). Real-world efficiency may vary.

- - Power drawn from the battery (P_batt) = P_load / η

- - P_batt = 5W / 0.85 ≈ 5.88 Watts

-

-**3. Calculate Current Drawn from Battery:**

- - Battery Nominal Voltage (V_batt) = 12V

- - Current drawn from battery (I_batt) = P_batt / V_batt

- - I_batt = 5.88W / 12V ≈ 0.49 Amps

-

-**4. Compare to Rated Discharge:**

- - The battery's capacity (2.6Ah) is rated for a 20-hour discharge (as noted in the file: `12V2.6Ah/20hr`).

- - Rated Discharge Current (I_rated) = 2.6Ah / 20h = 0.13 Amps

- - The calculated draw (0.49A) is significantly higher than the rated discharge current (0.13A).

-

-**5. Calculate Ideal Runtime (Ignoring Peukert's Effect):**

- - Battery Capacity (C) = 2.6Ah

- - Ideal Runtime (T_ideal) = C / I_batt

- - T_ideal = 2.6Ah / 0.49A ≈ 5.3 hours

-

-**6. Consider Peukert's Effect:**

- - Lead-acid batteries deliver less total capacity when discharged at rates higher than their rating (Peukert's Law).

- - Since 0.49A is much higher than the 0.13A rating, the *effective* capacity will be lower than 2.6Ah.

-

-**Conclusion:**

-

-The **ideal calculated runtime is approximately 5.3 hours**. However, due to the higher discharge current (0.49A vs. the 0.13A rating), the actual runtime will be **noticeably less than 5.3 hours**. The exact reduction depends on the specific Peukert exponent of this battery model, which is not provided.

-

-

-## app

-

-- [[power-storage-dat]]

-

-## ref

-

-- [[Lead-acid-battery]]

-

-# active-battery-balancing-board-dat

-

-An **active battery balancing board** for lithium batteries ensures that all cells in a battery pack maintain the same voltage level during charging and discharging. It actively redistributes energy between cells, transferring charge from higher-voltage cells to lower-voltage ones. This helps:

-

-- **Improve Battery Life**: Prevents overcharging or over-discharging of individual cells, reducing wear and extending the overall lifespan of the battery pack.

-- **Enhance Performance**: Ensures consistent voltage across cells, improving the efficiency and reliability of the battery.

-- **Increase Safety**: Reduces the risk of overheating, overcharging, or cell failure due to imbalances.

-- **Optimize Capacity**: Maximizes the usable capacity of the battery pack by ensuring all cells are equally charged.

-

-This is especially important in applications like electric vehicles, power tools, and energy storage systems.

-

-

-

-# rechargerable-battery-dat

-

-

-| **Battery Type** | **Typical Charge Time** | **Notes** |

-|----------------------|-------------------------|-------------------------------------------------------|

-| **Lead-acid** | 8-12 hours | Slow charge time, can be faster with a fast charger. |

-| **LFP (Lithium Iron Phosphate)** | 2-4 hours | Similar to lithium-ion but may take slightly longer. |

-| **Lithium-ion (Li-ion)** | 1-3 hours | Fastest charging, especially with modern fast chargers.|

-

-

-

-

-

-

-## Types

-

-- [[Lead-Acid-Battery-dat]] - [[lithium-battery-dat]]

-

-# li-battery-app-dat

-

-

-## calculata density

-

-If the battery voltage is 72V, you can use the following formula to calculate the energy in kilowatt-hours (kWh):

-

-Energy (kWh) = (Battery Capacity (AH) × Voltage (V)) / 1000

-

-Substituting the values:

-

-Energy (kWh) = (50 AH × 72 V) / 1000 = 3.6 kWh

-

-So, a 50AH battery with a voltage of 72V equals 3.6 kWh.

-

-

-To calculate how many kilometers can be traveled per 1 kWh, we need to divide the total range (100-150 km) by the total energy (3.6 kWh).

-

-For the lower range (100 km): Kilometers per kWh = 100 km / 3.6 kWh ≈ 27.78 km/kWh

-

-For the higher range (150 km): Kilometers per kWh = 150 km / 3.6 kWh ≈ 41.67 km/kWh

-

-**So, for each 1 kWh, the vehicle can travel between 27.78 km and 41.67 km depending on conditions.**

-

-

-

-## ref

-

-

-- [[li-battery-app]] - [[lithium-battery]]

-

-- [[power-dat]]

-

-# LFP-dat

-

-== LFP == LiFePO4-Battery == Lithium Iron Phosphate == LiFePO₄

-

-LiFePO₄ (Lithium Iron Phosphate) is a type of Lithium-ion (Li-ion) battery, but it uses iron phosphate (FePO₄) as the cathode material instead of more commonly used materials like cobalt, manganese, or nickel.

-

-Key Characteristics:

-

-Chemistry: The main difference lies in the cathode material. LiFePO₄ batteries use iron phosphate instead of traditional lithium cobalt oxide (LiCoO₂) or other lithium-based cathode materials used in regular Li-ion batteries.

-

-

-

-A **LiFePO4 (Lithium Iron Phosphate)** battery is a type of lithium-ion battery that uses lithium iron phosphate as the cathode material. It is known for its durability, safety, and efficiency, making it ideal for a variety of applications.

-

-## Key Features and Benefits:

-

-1. **Long Lifespan**

- - Typically lasts for **2,000–5,000 charge cycles** or more, compared to 300–500 cycles for lead-acid batteries.

- - Highly durable and cost-effective over time.

-

-2. **Safety**

- - Chemically stable, with a lower risk of overheating or catching fire compared to other lithium-ion batteries.

- - Less prone to thermal runaway.

-

-3. **Lightweight**

- - Significantly lighter than lead-acid batteries, ideal for portable applications.

-

-4. **High Energy Density**

- - Provides high energy capacity relative to size and weight. Outperforms lead-acid batteries, though less energy-dense than some lithium-ion types.

-

-5. **Wide Temperature Range**

- - Performs efficiently between **-20°C and 60°C**.

-

-6. **Fast Charging**

- - Can accept higher charge currents, allowing faster recharging.

-

-7. **Low Self-Discharge**

- - Retains charge for long periods when not in use.

-

-8. **Environmentally Friendly**

- - Free of toxic heavy metals like lead or cadmium and more recyclable than other batteries.

-

----

-

-## Common Applications:

-1. **Solar Power Systems**

- - Used in residential and off-grid solar setups for energy storage.

-

-2. **Electric Vehicles (EVs)**

- - Popular for e-bikes, e-scooters, and some electric cars due to safety and longevity.

-

-3. **Marine and RV Batteries**

- - Ideal for boats, campers, and caravans due to lightweight and deep-cycle performance.

-

-4. **Backup Power**

- - Used in UPS (Uninterruptible Power Supplies) and energy storage systems.

-

-5. **Portable Electronics**

- - Found in power tools, medical devices, and portable power banks.

-

-6. **Treasure Hunting/Outdoor Activities**

- - Useful for portable metal detectors and outdoor equipment due to durability and long-lasting power.

-

----

-

-## Comparison with Lead-Acid Batteries:

-

-| Feature | LiFePO4 Battery | Lead-Acid Battery |

-|--------------------------|-----------------------------|-----------------------------|

-| Lifespan | 2,000–5,000+ cycles | 300–500 cycles |

-| Weight | ~50% lighter | Heavier |

-| Maintenance | Maintenance-free | Requires maintenance |

-| Depth of Discharge (DoD) | Up to 80–100% | 50–60% |

-| Energy Efficiency | ~95% | ~70% |

-| Charging Time | 2–4 hours (fast charging) | 6–12 hours |

-

-

-

-

-

-## Key Differences Between LiFePO4 and Lithium-Ion Batteries

-

-| Feature | **LiFePO4 (Lithium Iron Phosphate)** | **Generic Lithium-Ion (e.g., LiCoO₂)** |

-|--------------------------|---------------------------------------------|---------------------------------------------|

-| **Chemistry** | Lithium Iron Phosphate (LiFePO4) | Lithium Cobalt Oxide (LiCoO₂), Lithium Manganese Oxide (LiMn₂O₄), Lithium Nickel Manganese Cobalt Oxide (NMC), etc. |

-| **Lifespan** | 2,000–5,000+ cycles | 500–1,000 cycles |

-| **Energy Density** | Lower (~90–120 Wh/kg) | Higher (~150–250 Wh/kg) |

-| **Safety** | Extremely safe, resistant to overheating or fire | Less safe, more prone to overheating and thermal runaway |

-| **Cost** | Typically more expensive upfront | Less expensive upfront |

-| **Weight** | Slightly heavier | Lighter |

-| **Temperature Range** | Performs well in wide temperatures (-20°C to 60°C) | Narrower operating range |

-| **Discharge Rate** | Can handle high discharge rates | May degrade faster under high discharge |

-| **Environmental Impact** | More eco-friendly, contains no cobalt | May use cobalt, which has environmental and ethical concerns |

-

-## Why is LiFePO4 considered a type of lithium-ion battery?

-

-Both LiFePO4 and other lithium-ion batteries store energy through the movement of lithium ions between electrodes.

-

-The key difference lies in the cathode material (正极材料):

-- LiFePO4 uses **lithium iron phosphate**. (磷酸铁锂)

-- Generic lithium-ion batteries often use **cobalt-based chemistries** (e.g., LiCoO₂). (基于钴的化学材料)

-

-

-## When to Choose LiFePO4 Over Other Lithium-Ion Chemistries?

-

-1. Safety is a priority:

-LiFePO4 is more thermally stable and less likely to overheat, catch fire, or explode.

-

-2. Long lifespan needed:

-Ideal for applications requiring thousands of charge/discharge cycles (e.g., solar systems, EVs, backup power).

-

-3. High discharge/charge rates:

-Suitable for applications like power tools or outdoor equipment.

-

-4. Eco-consciousness:

-LiFePO4 batteries are free of cobalt, which is often associated with environmental and ethical issues.

-

-

-

-

-

-## safest battery - Lithium Iron Phosphate (LiFePO4)

-

-The safest batteries to use, especially in terms of preventing fires or explosions, are Lithium Iron Phosphate (LiFePO4) batteries. They are known for their thermal and chemical stability compared to other lithium-ion batteries. Here are some key points about them:

-

-- Safety: LiFePO4 batteries are less likely to overheat, catch fire, or explode because of their higher thermal runaway threshold. They also have better stability during overcharging and short-circuit conditions.

-- Longer lifespan: These batteries tend to last longer than other types, reducing the need for frequent replacements.

-- Stable chemistry: Their chemical structure is more resistant to thermal changes, which makes them safer even in extreme conditions.

-

-- LiFePO4 - https://www.youtube.com/watch?v=07BS6QY3wI8&ab_channel=HighTechLab

-

-

-

-# Ternary-Lithium-Battery-dat.md (NCM/NCA)

-

-

-Ternary lithium batteries (**NCM or NCA**) are a type of **lithium-ion battery** that use **Nickel (Ni), Cobalt (Co), and Manganese (Mn) or Aluminum (Al)** as the primary cathode materials. They are widely used in **electric vehicles (EVs), power tools, and consumer electronics** due to their **high energy density and long cycle life**.

-

----

-

-## **Features of Ternary Lithium Batteries**

-1. **High Energy Density**

- - Higher than lithium iron phosphate (LFP) batteries, providing longer driving ranges.

-2. **Excellent Charge/Discharge Performance**

- - Supports high-power charging and discharging, making fast charging possible.

-3. **Better Low-Temperature Performance**

- - Performs better than LFP batteries in cold environments.

-4. **Shorter Cycle Life**

- - Typically **1,000–2,000 cycles**, compared to **4,000+ cycles for LFP batteries**.

-5. **Lower Safety**

- - **More prone to thermal runaway**, requiring advanced battery management systems (BMS) and cooling solutions.

-6. **Higher Cost**

- - **Cobalt is expensive and scarce**, increasing production costs.

-

----

-

-## **Comparison: NCM vs. NCA**

-| Type | Main Composition | Energy Density | Cycle Life | Cost | Safety | Main Applications |

-|-------|-----------------|---------------|-----------|------|------|----------------|

-| **NCM** (Nickel-Cobalt-Manganese) | Ni, Co, Mn | High | Medium | High | Medium | Passenger EVs, power tools |

-| **NCA** (Nickel-Cobalt-Aluminum) | Ni, Co, Al | Higher | Slightly lower | Higher | Lower | Tesla EVs |

-

-- **NCM batteries** offer a balanced performance.

-- **NCA batteries** provide the highest energy density but are more prone to overheating. Tesla primarily uses NCA batteries.

-

----

-

-## **Ternary Lithium vs. Lithium Iron Phosphate (LFP)**

-| Feature | Ternary Lithium (NCM/NCA) | Lithium Iron Phosphate (LFP) |

-|----------|----------------------|----------------------|

-| **Energy Density** | High (200–300Wh/kg) | Low (140–180Wh/kg) |

-| **Cycle Life** | 1,000–2,000 cycles | 4,000–8,000 cycles |

-| **Safety** | Lower, prone to thermal runaway | High, stable at high temperatures |

-| **Low-Temperature Performance** | Good, operates at -20°C | Poor, significant capacity loss in cold weather |

-| **Cost** | High (due to expensive cobalt & nickel) | Lower (cobalt-free, cheaper materials) |

-| **Applications** | High-end EVs, consumer electronics | Budget EVs, energy storage |

-

----

-

-## **Applications of Ternary Lithium Batteries**

-1. **Electric Vehicles (EVs)**

- - Used by **Tesla (NCA), BYD, NIO, XPeng, Li Auto**, and other manufacturers.

-2. **Power Tools**

- - Common in **electric drills, saws, and screwdrivers** that require high power.

-3. **Consumer Electronics**

- - Found in **smartphones, laptops, and tablets**.

-

----

-

-## **Future Trends**

-- **High-Nickel Batteries** (Reducing cobalt to lower costs, e.g., NCM811)

-- **Solid-State Batteries** (Improving safety and energy density)

-- **Recycling and Sustainability** (Reducing environmental impact)

-

-# li-battery-material-dat

-

-- [[LFP-dat]] - [[NCA-dat]] - [[NCM-dat]]

-

-

-- [[lithium-battery-dat]]

-

-# Li-Po-battery-dat

-

-

-

-

-- ExtremelySafe

-- Light-weighted

-- Versatileinnature

-- Low self-discharge level

-- Thin with huge capacity

-

-

-## Lithium Polymer Batteries

-

-### Overview

-Lithium Polymer batteries use a polymer electrolyte instead of a liquid electrolyte, making them more efficient and safer. This technology appeared in the 1970s and has recently been adopted in smartphones. LiPo batteries are versatile and available in various shapes and sizes.

-

-### Merits

-1. **Extremely Safe**: LiPo batteries have flexible aluminum packaging that protects them from explosions or hazardous situations.

-2. **Lightweight**: They are highly portable due to the absence of heavy metals or liquid electrolytes.

-3. **Versatile**: LiPo batteries can be customized into different shapes and sizes, offering flexibility in design.

-4. **Low Self-Discharge**: They have a low self-discharge rate, meaning they retain charge well when not in use.

-5. **High Capacity**: Despite being thin (even below one millimeter), LiPo batteries have high capacities and are 10 to 15% stronger than other batteries of the same size.

-

-### Demerits

-

-1. **High Cost**: LiPo batteries are more expensive compared to other battery types of the same size and specifications.

-2. **Lower Energy Density**: They are less efficient in terms of energy density and have fewer charge cycles compared to Li-Ion batteries.

-3. **Shorter Lifespan**: The decay cycle of LiPo batteries is shorter, making them less long-lasting than Li-Ion batteries.

-

-

-## Compare

-

-

-

-

-

-

-## Li-ion VS Li-Poly Battery

-

-| Feature | **Li-ion Battery** | **Li-Poly Battery** |

-|-----------------------|----------------------------------------------------------|----------------------------------------------------------|

-| **Electrolyte** | Liquid or gel electrolyte. Requires a hard casing to contain the liquid. Can be more volatile and prone to leakage if damaged. | Solid or gel-like polymer electrolyte. More stable, flexible, and less prone to leakage. |

-| **Shape/Size** | Typically **cylindrical** or **prismatic** in rigid, metal casings. Bulkier design, limiting shape flexibility. | Can be made in **custom shapes** and **sizes**, including thinner, flat, or flexible designs, allowing for more space-efficient configurations. |

-| **Weight/Size** | **Heavier** due to metal casing. Bulkier, typically used for larger devices. | **Lighter** and **more compact** due to the flexible polymer casing, ideal for small, thin devices like smartphones and wearables. |

-| **Energy Density** | Generally **higher energy density**, meaning more power for the same weight and volume. This gives longer battery life in large devices. | **Lower energy density** than Li-ion batteries, meaning slightly shorter battery life per charge, but improvements in technology can minimize this difference. |

-| **Durability/Safety** | **Less durable**; susceptible to damage, leakage, or fire if punctured or overcharged. Requires more protective circuitry to prevent overheating and short circuits. | **More durable and safer**; less prone to leakage, rupture, or combustion. It has a lower risk of damage, making it safer in small, thin devices. |

-| **Charging Speed** | Can **charge faster** due to higher energy density, and faster charging systems are more commonly available. | **Slower charging speed** compared to Li-ion due to higher resistance in the polymer electrolyte, though the difference can be minor depending on the device. |

-| **Lifespan** | Typically lasts **longer** (500-1000 charge cycles), especially for larger applications like laptops, power tools, and electric vehicles. | **Shorter lifespan** (300-500 cycles) compared to Li-ion, though this may be less of an issue in smaller devices or low-drain applications. |

-| **Applications** | Commonly used in **larger, power-demanding devices** such as laptops, electric vehicles, and power tools where higher energy density is a priority. | More often used in **smaller, portable electronics** like smartphones, drones, wearables, and tablets, where compact size and flexibility are important. |

-| **Cost** | **More cost-effective** per unit of energy and storage, especially in larger battery configurations. | **Slightly more expensive** to manufacture due to the polymer design and materials used. |

-| **Performance in Extreme Temperatures** | Li-ion batteries generally have a **wider operating temperature range**, but may degrade faster in high or low temperatures. | Li-Poly batteries are more **sensitive to extreme temperatures**, potentially leading to quicker degradation in high heat or low cold, though this can depend on the specific chemistry used. |

-| **Environmental Impact** | **Higher environmental impact** due to the complexity of materials and disposal, though efforts are being made for recycling improvements. | Typically **lower environmental impact**, with polymer materials that can be easier to recycle than the metals used in Li-ion batteries. However, both types still have significant environmental concerns. |

-

-# li-ion-battery-dat

-

-

-

-

-## How to revive / repair / fix a li-ion battery

-

-- https://www.youtube.com/watch?v=M-rqGF3NW8M&list=PLNgzTn8HTYzZhmBzrffCIMSWORd4BJm_l&index=24

-

-constant charging by a 4.3V 300mA CC/CV power supply

-

-

-## Check the Battery's Protection Circuit (BMS)

-

-Some lithium batteries have a protection circuit that cuts off charging if the voltage drops too low (below 2.5V or so). In some cases, you may need to bypass or reset the BMS to allow charging again. However, this can be risky, and it’s not recommended unless you’re experienced with battery repair.

-

-- [[battery-charger-dat]]

-

-- [[BMS-dat]]

-

-

-

-## ref

-

-# 18650

-

-18mm x 65mm

-

-

-

-- [[18650-battery-holder-dat]]

-

-## discharge current

-

-### 🔧 Typical Discharge Ratings by Category

-

-| **Category** | **Examples** | **Max Continuous Discharge** | **Notes** |

-|--------------------------|--------------------------|-------------------------------|-------------------------------------------|

-| **Standard Energy Cells** | Panasonic NCR18650B | 2A–3A | High capacity (up to 3400mAh), low drain |

-| | LG MJ1, Samsung 35E | 5A | Up to ~3500mAh |

-| **Balanced Cells** | Samsung 30Q, LG HG2 | 10A–15A | Good mix of capacity (3000mAh) and power |

-| **High-Drain Cells** | Sony VTC6, Molicel P26A | 20A | Often 2600–3000mAh |

-| **Extreme High-Drain** | Sony VTC5A, Molicel P28A | 25A–30A | Used in power tools, e-skates, vaping |

-

----

-

-### 📌 Notes

-

-- **Pulse current** (short bursts) may be 1.5–2× the continuous rating.

-- Always check **manufacturer datasheet** for:

- - Continuous discharge current

- - Pulse current (duration & cooldown)

- - Required cooling

-- Actual safe discharge also depends on:

- - Temperature

- - Battery aging

- - Internal resistance

-

----

-

-### ⚠️ Warning

-

-Using a cell above its rated discharge current may:

-- Cause overheating or thermal runaway

-- Reduce lifespan drastically

-- Trigger BMS protection or cause fire risk

-

----

-

-### ✅ Recommended Use

-

-| **Application** | **Recommended Cell Type** |

-|-----------------------|---------------------------------|

-| Flashlights, DIY packs | Standard or balanced (5A–10A) |

-| E-bikes, e-scooters | High-drain (15A–30A) |

-| Power tools, drones | High to extreme high-drain |

-

-

-

-## 14500 vs 18650 vs 21700 batteries

-

-| Feature | AA Size Lithium (14500) | 18650 Lithium-Ion | 21700 Lithium-Ion |

-| ---------------------------- | -------------------------- | --------------------------- | ------------------------- |

-| **Typical Size (mm)** | 14 x 50 | 18 x 65 | 21 x 70 |

-| **Nominal Voltage** | 3.7V | 3.6V – 3.7V | 3.6V – 3.7V |

-| **Capacity Range** | 500 – 800 mAh | 1800 – 3500 mAh | 4000 – 5000+ mAh |

-| **Max Continuous Discharge** | 1 – 3A | 5 – 20A | 10 – 35A |

-| **Common C-Rate** | 1C – 3C | 1C – 10C | 1C – 10C+ |

-| **Rechargeable** | Yes | Yes | Yes |

-| **Common Use Cases** | Small flashlights, sensors | Laptops, power tools, vapes | EVs, e-bikes, power tools |

-| **Weight (approx.)** | ~20g | ~45g | ~70g |

-| **Energy Density** | Low – Medium | Medium | High |

-

-

-

-

-## **18650 Battery Types**

-

-| **Type** | **Main Composition** | **Features** | **Applications** |

-| --------------------------------- | ------------------------------------------------ | ------------------------------------------------ | --------------------------------------- |

-| **NCM/NCA** | Nickel-Cobalt-Manganese / Nickel-Cobalt-Aluminum | High energy density, medium safety | EVs (Tesla Model S/X), laptop batteries |

-| **LFP (Lithium Iron Phosphate)** | Lithium Iron Phosphate | Long lifespan, high safety, lower energy density | Energy storage, power tools, e-bikes |

-| **LCO (Lithium Cobalt Oxide)** | Lithium Cobalt Oxide | High energy density, shorter lifespan | Laptops, battery packs |

-| **IMR (Lithium Manganese Oxide)** | Lithium Manganese Oxide | High discharge rate, heat resistance | High-power flashlights, vaping devices |

-

----

-

-## **18650 vs. 21700 Batteries**

-| **Model** | **Size** | **Energy Density** | **Common Uses** |

-| --------- | ---------- | ------------------ | ------------------------------- |

-| **18650** | 18 × 65 mm | 2000 – 3500mAh | Laptops, EVs, tools |

-| **21700** | 21 × 70 mm | 4000 – 5000mAh | Tesla batteries, energy storage |

-

-Tesla originally used **18650 batteries** in **Model S/X** but later switched to **21700** for **Model 3/Y** and is now moving towards **4680** cells for higher efficiency.

-

-

-The 18650 battery should fall under the Lithium-ion Battery category, as it is a specific form factor of the lithium-ion battery, commonly used in applications such as laptops, power tools, flashlights, and electric vehicles.

-

-## safety concern

-

-After 30 years of development, the preparation process of 18650 battery has been very mature. In addition to the great improvement in performance, its safety is also perfect.

-

-To prevent the metal casing from exploding, the battery is now fitted with a safety valve at the top. The safety valve is now a standard part of every 18650 Li-ion battery and is the most important barrier. When the pressure inside the cell becomes too high, the top safety valve opens to vent and depressurize, preventing an explosion.

-

-However, when the safety valve is open, chemicals leaking from inside the battery can react with oxygen in the air at high temperatures and still cause a fire.

-

-In addition, most 18650 batteries now also come with their own protection panel with overcharge and overdischarge and short circuit protection, which has high safety performance.

-

-- [[battery-protection-dat]]

-

-

-## CID safety

-

-The CID (Current Interrupt Device) in an 18650 battery is a safety feature designed to prevent overheating and potential hazards. If the internal pressure of the battery gets too high (usually due to overcharging or overheating), the CID disconnects the circuit, stopping the current flow to prevent a dangerous situation, such as thermal runaway or explosion.

-

-Each manufacturer might have slightly different specifications, but the CID is a common safety component in lithium-ion batteries, especially in high-capacity cells like the 18650.

-

-

-### CID reset trick

-

-- https://www.youtube.com/watch?v=IhUtKvCV6fs&ab_channel=WalamusPrime

-

-

-

-### 🔒 What is CID Safety for 18650 Batteries?

-

-#### What is CID?

-

-- **CID** stands for **Current Interrupt Device**.

-- It is a **built-in safety mechanism** inside many 18650 lithium-ion cells.

-- Designed to **prevent dangerous overpressure and overheating**.

-

----

-

-#### How Does CID Work?

-

-- The CID is a **pressure-sensitive switch** inside the cell.

-- When internal gas pressure rises above a certain threshold (due to:

- - Overcharging,

- - Short circuit,

- - Thermal runaway),

-

- the CID **disconnects the internal current path**.

-- This **interrupts current flow**, effectively stopping the battery from further charging or discharging.

-- It **helps prevent cell rupture, fire, or explosion**.

-

----

-

-#### Why Is CID Important?

-

-- Lithium-ion cells generate gas if damaged or overcharged.

-- Pressure build-up can cause catastrophic failure.

-- CID acts as a **last-resort safety valve** inside the cell.

-- It **works alongside external protection circuits and BMS**.

-

----

-

-#### Summary Table

-

-| Feature | Description |

-|-----------------------|------------------------------------------------|

-| Purpose | Prevent overpressure and overheating |

-| Mechanism | Pressure-activated internal switch |

-| Activation Threshold | Specific pressure level inside the cell |

-| Effect | Interrupts internal circuit to stop current flow |

-| Role | Safety backup inside individual 18650 cells |

-

----

-

-#### Important Notes

-

-- CID **does not reset** after activation; cell is permanently disabled.

-- Cells with CID still **require external protection** (BMS).

-- Not all lithium cells have CID — mostly found in high-quality 18650s.

-

-### short test

-

-- https://www.youtube.com/watch?v=bKQzfrO6WBA&ab_channel=EngineerX

-- https://www.youtube.com/watch?v=AUMiSk1D4Xg&ab_channel=DIYTech%26Repairs

-

-

-## 🔋 How to Use 18650 Batteries Safely

-

-### 1. Choose Quality Batteries

-

-- Buy from **reputable brands** (Panasonic, Samsung, LG, Sony, Molicel)

-- Avoid cheap or counterfeit cells

-- Check for **safety features** like CID and PCM

-

----

-

-### 2. Use Proper Chargers

-

-- Use a charger designed for **Li-ion 18650 cells**

-- Prefer chargers with **constant current / constant voltage (CC/CV)** charging profile

-- Avoid using chargers designed for other chemistries

-

----

-

-### 3. Never Overcharge or Overdischarge

-

-- Do not charge above **4.2V per cell**

-- Do not discharge below **2.5V per cell**

-- Use a **Battery Management System (BMS)** for packs

-

----

-

-### 4. Avoid Short Circuits

-

-- Do not let battery terminals touch metal objects

-- Use protective holders or cases

-- Handle with care to avoid damaging the cell casing

-

----

-

-### 5. Prevent Physical Damage

-

-- Avoid dropping, crushing, or puncturing cells

-- Do not expose to extreme temperatures (keep between 0°C and 45°C for charging)

-

----

-

-### 6. Store Properly

-

-- Store batteries in a **cool, dry place**

-- Keep batteries at around **40-60% charge** for long-term storage

-- Use battery cases to prevent accidental shorts

-

----

-

-### 7. Monitor Battery Health

-

-- Check for swelling, corrosion, or leaks

-- Dispose of damaged or old batteries safely at designated recycling centers

-

----

-

-### 8. Use Appropriate Protection Circuits

-

-- For battery packs, use a **BMS** to prevent overcharge, overdischarge, overcurrent, and short circuit

-- Individual protected 18650 cells include an internal **PCM (Protection Circuit Module)**

-

----

-

-### Summary Table

-

-| Safety Tip | Description |

-|---------------------------|-------------------------------------|

-| Buy quality cells | Avoid counterfeit or low-grade cells |

-| Use correct charger | CC/CV chargers designed for Li-ion |

-| Avoid overcharge/discharge | Charge max 4.2V, discharge min 2.5V |

-| Prevent short circuits | Use protective cases and careful handling |

-| Avoid physical damage | Do not crush, puncture, or overheat |

-| Store at partial charge | 40–60% SOC in cool, dry place |

-| Use BMS/PCM | Protect against electrical faults |

-

-

-

-## how to revive 18650 batteries at 0V

-

-## ✅ Tools You’ll Need

-- Multimeter

-- Smart charger (with 0V recovery mode) *or* TP4056 / bench power supply

-- Optional: Resistor (10–50Ω) for current limiting

-

-### 🔧 Method 1: Smart Charger with 0V Recovery

-Some chargers (e.g., **LiitoKala Lii-500**, **Nitecore**) can automatically revive 0V cells.

-

-#### Steps:

-1. Insert the battery into the charger.

-2. If supported, it will trickle charge until voltage reaches ~3.0V.

-3. Then it continues normal charging.

-4. Monitor temperature and voltage during charging.

-

-> ✅ **Low risk**

-> ✅ **Recommended method**

-> ✅ **High success rate** for mildly over-discharged cells

-

----

-

-### 🔧 Method 2: Manual Trickle Charge (Bench PSU / TP4056)

-Only attempt if you are **experienced with electronics**.

-

-#### Steps:

-1. Set PSU to **3.0–3.2V**, current limit to **50–100mA**.

-2. Connect positive and negative terminals (double-check polarity!).

-3. Charge slowly until voltage rises to **2.5–3.0V**.

-4. Disconnect and let the cell rest for 10–15 minutes.

-5. If voltage holds, continue charging normally to **4.2V at 500–1000mA**.

-6. If voltage drops again → **discard the cell**.

-

-> ⚠️ **Medium risk**

-> ⚠️ **Requires attention and monitoring**

-

----

-

-### ✅ After Revival

-Check:

-- 🔋 Voltage stability: Does it stay above 3.0V after rest?

-- 🌡️ Temperature: Any excessive heat during charging or discharging?

-- 🔋 Capacity: Use a charger/tester to measure actual mAh.

-

----

-

-### ❌ Do NOT Attempt Revival If:

-- Battery is **swollen**, **leaking**, or **rusty**

-- Voltage **does not rise** after 10–20 mins of trickle charge

-- Cell gets **hot quickly** during charging

-

----

-

-### ♻️ Safe Disposal

-Dispose of dead batteries at **electronics recycling** centers.

-Do **not** throw in regular trash.

-

----

-

-### 🔄 Summary Table

-

-| Method | Risk Level | Tools Needed | Notes |

-|------------------------|------------|--------------------------|---------------------------------|

-| Smart Charger (0V mode)| ✅ Low | Li-ion charger | Safest and easiest method |

-| Manual Trickle Charge | ⚠️ Medium | Bench PSU or TP4056 | Monitor voltage & temperature |

-| Force-Charge (unsafe) | ❌ High | Not recommended | Risk of fire or explosion |

-

-

-

-

-

-## battery rack

-

-- [[week-4-8-dat]]

-

-## ref

-

-- [[lithium-battery-dat]]

-

-

-

-# 26650-dat

-

-

-

-## motorbike battery

-

-- 12-14 milliohm internal resistance

-- [[active-battery-balancing-board-dat]]

-- internal 4x2 = 14.5 V

-- 10C / Instant discharge 20C

-

-

-

-

-

-# li-battery-size-dat

-

-- [[18650-dat]] - [[21700-dat]] - [[26650-dat]] - [[32650-dat]] - [[32700-dat]] - [[A123-battery-dat]] - [[LFP-battery-dat]] - [[LTO-battery-dat]] - [[LTO-18650-battery-dat]] - [[LTO-26650-battery-dat]] - [[LTO-32700-battery-dat]] - [[LTO-32650-battery-dat]]

-

-- [[pouch-battery-dat]]

-

-

-- 21700: 21mm diameter, 70mm length. Increasingly popular, offering higher capacity than 18650.

-- 26650: 26mm diameter, 65mm length. Larger capacity and often higher discharge current capability than 18650.

-- 14500: 14mm diameter, 50mm length. Same physical size as a standard AA battery.

-- 16340: 16mm diameter, 34mm length. Same physical size as a CR123A battery.

-- 10440: 10mm diameter, 44mm length. Same physical size as a standard AAA battery.

-- 32650 / 32700: 32mm diameter, 65mm or 70mm length. Often used for LiFePO4 chemistry, providing high power and capacity.

-

-

-## ref

-

-- [[18650]]

-

-# pouch-battery-dat

-

-

-

-

-

-## **Characteristics of Pouch Batteries**

-1. **Lightweight Design**

- - Uses **aluminum-plastic film**, making it lighter than metal-cased batteries.

-2. **High Energy Density**

- - Pouch batteries have **10%-15% higher volumetric energy density** than prismatic and cylindrical batteries, ideal for long-range applications.

-3. **Better Safety**

- - In case of damage, pouch batteries **swell and vent gas instead of exploding**, making them safer than cylindrical cells.

-4. **Flexible Shape and Size**

- - Can be **customized to fit different device designs**, making them ideal for **compact electronic devices and high-end EVs**.

-5. **Lower Mechanical Strength**

- - The **soft casing is more prone to damage** and requires additional structural protection.

-6. **Higher Production Cost**

- - Manufacturing is **more complex and expensive** than cylindrical or prismatic cells.

-

----

-

-## **Pouch vs. Cylindrical vs. Prismatic Batteries**

-| **Type** | **Casing Material** | **Energy Density** | **Safety** | **Weight** | **Applications** |

-|---------|----------------|----------------|------------|--------|----------------|

-| **Pouch Battery** | Aluminum-plastic film | **Highest** | High (Swells instead of exploding) | **Lightest** | **High-end EVs, smartphones, laptops, drones** |

-| **Cylindrical Battery (18650/21700)** | Stainless steel shell | Medium | Medium (Has safety valves) | Heavy | **EVs (Tesla), laptops, power tools** |

-| **Prismatic Battery** | Aluminum or steel case | High | Medium (Rigid structure) | Medium | **EVs, energy storage systems** |

-

----

-

-## **Applications of Pouch Batteries**

-1. **Electric Vehicles (EVs)**

- - Used by **BYD, NIO, Hyundai, BMW**, and other manufacturers.

-2. **Consumer Electronics**

- - Common in **smartphones, laptops, tablets**, and other portable devices.

-3. **Energy Storage Systems**

- - Some **home and commercial energy storage systems** use pouch batteries for higher energy density.

-4. **Drones & E-Mobility**

- - Due to their **lightweight design**, pouch batteries are preferred for **drones, e-skateboards, and lightweight EVs**.

-

----

-

-## **Future Trends**

-- **High-Nickel Chemistry** (Improving energy density, reducing cobalt usage)

-- **Solid-State Batteries** (Enhancing safety and increasing energy capacity)

-- **Recycling & Sustainability** (Reducing environmental impact and improving recyclability)

-

----

-

-## Soft-pack (pouch) battery

-

-

-A Soft-pack Pouch Lithium Battery (or Pouch-type Lithium Battery) refers to a specific form factor of Lithium-ion or Lithium-Polymer (Li-Poly) batteries that is encased in a flexible, soft pouch made of materials like aluminum foil. This type of battery is typically lighter and more compact compared to cylindrical cells (like 18650) or prismatic cells, and it offers certain advantages in terms of flexibility, form factor, and space efficiency.

-

-1. Good safety performance:

-

-The soft packing battery does not cause an explosion accident as like the steel shell battery or aluminum shell battery. Generally, in the case of a safety hazard, the outer casing will only bulge at most.

-

-2. Small size, light weight, high energy:

-

-in terms of weight, the soft pack battery is 40% lighter than the equivalent capacity of the steel casing lithium battery, and 20% lighter than the aluminum casing battery. In terms of capacity, the soft-pack lithium battery is 10-15% higher than the steel casing battery of the same specification scale, and 5-10% higher than the aluminum casing battery.

-

-3. The internal resistance is small:

-

-We all know that the lithium battery itself will have an inevitable self-discharge reaction, and the greater the internal resistance, the more intense the self-discharge. Relatively speaking, the internal resistance of the soft-pack lithium battery is small, which greatly reduces the self-consumption of the battery.

-

-4. Flexible planning:

-

-the shape of the soft pack battery can be determined by specific business needs, customized planning according to the detailed dimensions of the battery box, perhaps through a variety of battery arrangements to achieve full use of the internal space of the battery box, to meet Differentiated needs.

-

-

-

-# lithium-battery-dat

-

-## info

-

-- [[BMS-dat]] - [[battery-charger-dat]]

-

-- [[active-battery-balancing-board-dat]] - [[battery-soldering-dat]]

-

-- high current wires == [[AWG-wires-dat]]

-

-## Classification Summary

-

-By Electrode Materials - [[LFP-dat]] - [[Ternary-Lithium-Battery-dat]]

-

-By Electrode Materials Status - [[li-ion-battery-dat]] - [[lipo-battery-dat]]

-

-By size - [[18650-dat]] - [[26650-dat]]

-

-

-### By Apps

-

-Robot tank battery

-

-

-

-

-

-## Classification

-

-

-### **1. Classification by Electrode Materials**

-

-#### **(1) Positive Electrode Materials**

-

-- **Lithium Cobalt Oxide (LiCoO₂)**

- - **Characteristics**: High energy density, suitable for portable devices, but expensive and less thermally stable with shorter cycle life.

- - **Applications**: Smartphones, laptops, cameras, etc.

-

-- **Nickel Cobalt Aluminum (NCA)**

- - **Characteristics**: High energy density and long cycle life, widely used in electric vehicles (EVs).

- - **Applications**: Electric vehicles, battery packs, etc.

-

-- **Nickel Cobalt Manganese (NCM)**

- - **Characteristics**: Balanced performance, high energy density, and long cycle life. The performance can vary depending on the ratio of nickel, cobalt, and manganese.

- - **Applications**: Electric vehicles, battery packs, etc.

-

-- **Lithium Iron Phosphate (LiFePO₄)**

- - **Characteristics**: High safety, good thermal stability, low cost, but lower energy density.

- - **Applications**: Electric vehicles, energy storage systems, low-power devices.

-

-- **Lithium Manganese Oxide (LiMn₂O₄)**

- - **Characteristics**: Safe and stable, but slightly lower energy density and capacity compared to lithium cobalt oxide.

- - **Applications**: Power tools, e-bikes, battery packs.

-

-#### **(2) Negative Electrode Materials**

-

-- **Graphite**

- - **Characteristics**: Most common negative electrode material, low cost, good conductivity, and cycle performance.

- - **Applications**: Most Li-ion batteries, including smartphones and laptops.

-

-- **Silicon-based Materials**

- - **Characteristics**: Silicon has a high theoretical capacity but suffers from expansion and contraction issues, usually used in composite materials with graphite.

- - **Applications**: High-capacity batteries, electric vehicles, smartphones.

-

-- **Silicon-Carbon Composite**

- - **Characteristics**: Combines the high energy density of silicon with the stability of carbon, offering better performance than traditional graphite.

- - **Applications**: High-performance batteries, especially in electric vehicles and storage systems.

-

-- **Lithium Titanate (Li₄Ti₅O₁₂)**

- - **Characteristics**: Better safety and longer cycle life but lower energy density, stable discharge voltage.

- - **Applications**: High-power, long-lifetime applications.

-

----

-

-

-

-### **Classification of Lithium-ion Batteries by Size**

-

-Lithium-ion batteries can be classified into different sizes depending on their **form factor**, **capacity**, and **voltage**. The most common types of lithium-ion batteries based on size include cylindrical, prismatic, and pouch batteries. Below is a detailed classification based on size:

-

----

-

-#### **1. Cylindrical Lithium-ion Batteries**

-

-Cylindrical lithium-ion batteries are among the most common and widely used in consumer electronics and electric vehicles. These batteries come in standardized sizes, providing easy options for manufacturers to integrate them into their products.

-

-##### **Common Sizes:**

-

-- **18650**

- - **Dimensions**: 18mm diameter, 65mm length

- - **Capacity**: Typically 2,000mAh - 3,500mAh

- - **Applications**: Laptops, power banks, electric vehicles, flashlights, etc.

-

-- **21700**

- - **Dimensions**: 21mm diameter, 70mm length

- - **Capacity**: Typically 3,000mAh - 5,000mAh

- - **Applications**: Electric vehicles, power tools, energy storage systems.

-

-- **26650**

- - **Dimensions**: 26mm diameter, 65mm length

- - **Capacity**: Typically 4,000mAh - 5,500mAh

- - **Applications**: Power tools, high-capacity power banks, solar energy storage.

-

----

-

-#### **2. Prismatic Lithium-ion Batteries**

-

-Prismatic lithium-ion batteries have a rectangular shape and are commonly used in applications where space utilization is critical. They are often used in electric vehicles and energy storage systems, as they can be more efficient in terms of volume compared to cylindrical batteries.

-

-##### **Common Sizes:**

-

-- **Small Prismatic Batteries**

- - **Dimensions**: Custom sizes, ranging from 50mm x 70mm to 100mm x 150mm

- - **Capacity**: Typically 1,000mAh - 5,000mAh

- - **Applications**: Consumer electronics, portable devices, and small power tools.

-

-- **Medium/High-Capacity Prismatic Batteries**

- - **Dimensions**: Custom sizes for electric vehicles or energy storage systems

- - **Capacity**: Typically 10,000mAh - 50,000mAh

- - **Applications**: Electric vehicles, industrial applications, solar energy storage.

-

----

-

-#### **3. Pouch Lithium-ion Batteries**

-

-Pouch lithium-ion batteries are flexible and can be designed into various shapes and sizes, making them ideal for applications where space and weight are important factors, such as in portable devices and wearable technologies.

-

-##### **Common Sizes:**

-

-- **Small Pouch Batteries**

- - **Dimensions**: Custom sizes for portable electronics, typically under 50mm x 100mm

- - **Capacity**: Typically 500mAh - 3,000mAh

- - **Applications**: Smartphones, tablets, drones, wearable devices.

-

-- **Large Pouch Batteries**

- - **Dimensions**: Custom sizes for energy storage systems, electric vehicles, and larger applications

- - **Capacity**: Typically 5,000mAh - 30,000mAh

- - **Applications**: Electric vehicles, energy storage systems, large power banks.

-

----

-

-#### **4. Coin Cell Lithium-ion Batteries**

-

-Coin cell batteries are small, disc-shaped batteries typically used in low-power applications where size and weight are critical, such as in hearing aids, remote controls, and watches.

-

-##### **Common Sizes:**

-

-- **CR2032**

- - **Dimensions**: 20mm diameter, 3.2mm thickness

- - **Capacity**: Typically 200mAh - 300mAh

- - **Applications**: Watches, medical devices, remote controls.

-

-- **CR2025**

- - **Dimensions**: 20mm diameter, 2.5mm thickness

- - **Capacity**: Typically 150mAh - 200mAh

- - **Applications**: Key fobs, fitness devices, and other small electronics.

-

----

-

-### **Summary**

-

-Lithium-ion batteries are classified based on their **size**, which influences their capacity, applications, and design flexibility. The most common categories based on size include **cylindrical, prismatic, pouch, and coin cell**. Below is a summary of the typical sizes:

-

-| **Battery Type** | **Common Sizes** | **Applications** |

-|---------------------------------|----------------------------|---------------------------------------------------------|

-| **Cylindrical Batteries** | 18650, 21700, 26650 | Laptops, electric vehicles, power banks, flashlights |

-| **Prismatic Batteries** | Custom sizes, 50mm x 70mm - 100mm x 150mm | Electric vehicles, energy storage, industrial applications |

-| **Pouch Batteries** | Custom sizes | Smartphones, tablets, wearable devices, drones, EVs |

-| **Coin Cell Batteries** | CR2032, CR2025 | Watches, medical devices, remote controls |

-

-This classification helps manufacturers and consumers select the appropriate battery type based on the size, capacity, and specific requirements of the application.

-

-

-

-## li-battery tech

-

-### Low Battery Voltage (Below Safe Threshold)

-

-Protection boards are designed to protect lithium batteries from over-discharge, overcharge, and short circuits. Many lithium battery protection circuits cut off the battery's output if the voltage drops below a certain threshold, often around 2.5V to 2.8V.

-

-If the battery is at **2.6V**, it's very close to this cutoff threshold, and the protection circuit may be designed to prevent any further discharge to avoid damaging the battery, which could explain the drop to 0V.

-

-

-

-

-### Lithium battery Check

-

-- battery voltage B+/B- = OK, output == 0V, BMS problem

-

-

-

-

-## 📋 Common Cylindrical Lithium-Ion Battery Types

-

-| Type | Size (mm) | Capacity Range (approx.) | Common Uses |

-|----------|---------------------|-------------------------------|-------------------------------------|

-| 14500 | 14 x 50 | 600–1000 mAh | Flashlights, small electronics |

-| 16340 | 16 x 34 | 700–1400 mAh | Flashlights, laser pointers |

-| 18350 | 18 x 35 | 800–1400 mAh | Compact flashlights, vaping mods |

-| 18650 | 18 x 65 | 1800–3500+ mAh | Laptops, power banks, e-bikes |

-| 21700 | 21 x 70 | 3000–5000+ mAh | Electric cars, high-performance tools|

-| 26650 | 26 x 65 | 4000–6000+ mAh | Flashlights, power tools, e-bikes |

-| 32650 | 32 x 65 | 6000–7000+ mAh | Energy storage, high-capacity uses |

-

-

-🧠 Which to Choose?

-18650: Most versatile and widely used.

-

-21700: Replacing 18650 in high-drain applications (e.g., Tesla).

-

-26650: Best for high-capacity flashlights and tools where size is less of a concern.

-

-Smaller types (e.g., 14500): Used in compact or AA-sized electronics.

-

-

-

-

-## 🔌 Notes on Battery Chemistry

-

-Most of these are Lithium-Ion (Li-ion) or Lithium Iron Phosphate (LiFePO₄):

-

-Li-ion: Higher energy density, common in consumer electronics.

-

-LiFePO₄: Lower energy density, but longer cycle life and more stable — often used in solar and industrial applications.

-

-## 🔒 Protected vs Unprotected

-

-Protected cells: Include a small circuit to prevent overcharge, overdischarge, and short-circuit.

-

-Unprotected cells: Require careful handling but are often used in custom battery packs or devices with built-in protection.

-

-

-

-

-

-## large battery

-

-48V

-200AH

-

-

-

-## ref

-

-- [[lithium-battery]]

-

-# lithium-power-battery-dat

-

-

-

-for electric-bike, electric-kart, electric-scooter, electric-skateboard, etc

-

-# portable-power-bank-dat

-

-### How Power Bank Capacity (e.g., 20000 mAh) is Calculated

-

-The capacity advertised on a power bank, such as 20000 mAh, typically represents the **total combined capacity of its internal battery cells**. Here's the breakdown:

-

-1. **Internal Battery Cells:**

- * Power banks contain one or more individual battery cells, usually Lithium-ion (Li-ion) or Lithium-polymer (Li-Po).

-

-2. **Individual Cell Capacity:**

- * Each internal cell has its own capacity rating, measured in milliampere-hours (mAh). Examples include 2500mAh, 3350mAh, 5000mAh per cell.

-

-3. **Parallel Connection:**

- * To achieve a higher total capacity, these individual cells are connected **in parallel** inside the power bank.

- * In a parallel circuit, the total capacity is the sum of the individual capacities.

-

-4. **Calculation Example:**

- * A 20000 mAh power bank might be constructed using:

- * 4 cells × 5000 mAh/cell = `20000 mAh`

- * 6 cells × ~3350 mAh/cell ≈ `20100 mAh` (often rounded down or marketed as 20000 mAh)

- * 8 cells × 2500 mAh/cell = `20000 mAh`

-

-**Key Considerations:**

-

-* **Cell Voltage:** This advertised capacity (e.g., 20000 mAh) is based on the **nominal voltage of the internal cells** (typically 3.6V or 3.7V).

-* **Output Voltage & Efficiency:** When charging a device, the power bank converts the internal cell voltage to the required output voltage (e.g., 5V, 9V, 12V via USB). This conversion process isn't 100% efficient; some energy is lost as heat.

-* **Rated Capacity:** Because of the voltage conversion and efficiency losses, the actual amount of charge delivered *to your device* at the output voltage will be lower than the internal cell capacity. This usable output is often listed separately as the **Rated Capacity** (e.g., "Rated Capacity: 12500mAh at 5V").

-

-

-## ref

-

-

-- [[injoinic-dat]] - [[IP5306-dat]] - [[IP5316-dat]]

-

-