Related Topics:
Store Lithium Based Batteries-
How many times do lithium batteries need to be powered before they explode
Lithium batteries typically endure between 300 to 500 charge cycles before their capacity significantly declines. A charge cycle is defined as one complete discharge and recharge of the battery.
FAQs about How many times do lithium batteries need to be powered before they explode
How many charging cycles can a lithium battery last?
The maximum number of charging cycles a lithium battery can endure depends on various factors, including the specific type of lithium battery. Different lithium battery chemistries have varying lifespans. For instance: Lithium-ion (Li-ion) batteries typically offer around 300-500 charging cycles before their capacity starts to degrade noticeably.
How long do lithium batteries last?
Lithium batteries typically endure between 300 to 500 charge cycles before their capacity significantly declines. A charge cycle is defined as one complete discharge and recharge of the battery. The lifespan of lithium batteries varies based on several factors.
How long should you charge a new lithium ion battery?
Overcharging can damage your battery and shorten its lifespan. As many of us know, it is best practice to charge a new lithium-ion battery for 8 hours before using it. This allows the battery to reach its full capacity and ensures optimal performance. However, there are a few things to keep in mind when charging your new battery for the first time.
Should you fully charge a lithium-ion battery?
If you're using a lithium-ion battery for the first time, it's important to fully charge it before use. This will help ensure that the battery performs optimally and lasts as long as possible. Here's what you need to know about charging a lithium-ion battery for the first time.
What is a charge cycle in lithium batteries?
A charge cycle in lithium batteries refers to the complete process of charging a battery from 0% to 100% and then discharging it back to 0%. This cycle indicates how many times a battery can be fully charged and discharged before its capacity diminishes significantly.
How fast should a lithium iron battery be charged?
To maximize the lifespan of your lithium iron battery, it's recommended to charge it at a rate no slower than C/4 but no faster than C/2. This charge rate strikes the right balance between efficiency and battery health. Charging at a slower rate may take longer, but it helps preserve the overall capacity of the battery over time.
-
How often should lithium iron phosphate batteries be charged
So, the key is to always, every time, charge your LiFePO4 batteries with a battery charger specifically designed to charge and maintain LiFePO4 lithium batteries.
FAQs about How often should lithium iron phosphate batteries be charged
How do I charge a lithium iron phosphate battery?
Follow the instructions and use the lithium charger provided by the manufacturer to charge lithium iron phosphate batteries correctly. During the initial charging, monitor the battery's charge voltage to ensure it is within appropriate voltage limits, generally a constant voltage of around 13V.
Why is battery management important for a lithium iron phosphate (LiFePO4) battery system?
Battery management is key when running a lithium iron phosphate (LiFePO4) battery system on board. Victron's user interface gives easy access to essential data and allows for remote troubleshooting.
How fast should a lithium iron battery be charged?
To maximize the lifespan of your lithium iron battery, it's recommended to charge it at a rate no slower than C/4 but no faster than C/2. This charge rate strikes the right balance between efficiency and battery health. Charging at a slower rate may take longer, but it helps preserve the overall capacity of the battery over time.
How many volts does a lithium phosphate battery take?
The nominal voltage of a lithium iron phosphate battery is 3.2V, and the charging cut-off voltage is 3.6V. The nominal voltage of ordinary lithium batteries is 3.6V, and the charging cut-off voltage is 4.2V. Can I charge LiFePO4 batteries with solar? Solar panels cannot directly charge lithium-iron phosphate batteries.
What is the charging method of a lithium phosphate battery?
The charging method of both batteries is a constant current and then a constant voltage (CCCV), but the constant voltage points are different. The nominal voltage of a lithium iron phosphate battery is 3.2V, and the charging cut-off voltage is 3.6V. The nominal voltage of ordinary lithium batteries is 3.6V, and the charging cut-off voltage is 4.2V.
How to charge a lithium ion battery?
Lithium-ion batteries are particularly sensitive to overcharging and discharging, so avoid charging more than 100% or discharging less than 20%. Charging when the battery power drops to about 30% is recommended. Keeping battery power between 40-80% can slow down the battery's cycle age. 2. Control charging time
-
How to adjust the current when charging lithium batteries
Utilizing a DC-to-DC charger or a battery isolation manager can help regulate the voltage and current during charging, ensuring your LiFePO4 batteries are charged safely and efficiently.
FAQs about How to adjust the current when charging lithium batteries
How does the voltage and current change during charging a lithium-ion battery?
Here is a general overview of how the voltage and current change during the charging process of lithium-ion batteries: Voltage Rise and Current Decrease: When you start charging a lithium-ion battery, the voltage initially rises slowly, and the charging current gradually decreases. This initial phase is characterized by a gentle voltage increase.
What happens if you charge a lithium ion battery below voltage?
Going below this voltage can damage the battery. Charging Stages: Lithium-ion battery charging involves four stages: trickle charging (low-voltage pre-charging), constant current charging, constant voltage charging, and charging termination. Charging Current: This parameter represents the current delivered to the battery during charging.
When is a lithium ion battery fully charged?
A lithium-ion battery is considered fully charged when the current drops to a set level, usually around 3% of its rated capacity. Some chargers may apply a topping charge to maintain the battery's voltage without risking overcharging, which is vital for extending battery life. 2. Safety Considerations
What is a lithium ion battery charging cut-off current?
This point is commonly referred to as the “charging cut-off current.” II. Key Parameters in Lithium-ion Battery Charging Several crucial parameters are involved in lithium-ion battery charging: Charging Voltage: This is the voltage applied to the battery during the charging process.
How does a lithium ion battery work?
This initial phase is characterized by a gentle voltage increase. Steady Voltage and Declining Current: As the battery charges, it reaches a point where its voltage levels off at approximately 4.2V (for many lithium-ion batteries). At this stage, the battery voltage remains relatively constant, while the charging current continues to decrease.
What voltage should a lithium battery be charged?
Understanding the charging voltages for lithium batteries is crucial for maintaining battery health and performance. This includes knowing the appropriate voltages for the bulk, absorption, and float stages of charging. For lithium batteries, the recommended voltage range for battery charging is between 14.2 and 14.6 volts.
-
How many batteries are needed to store 100gw of energy
For whole-home backup during a 3-day outage, you'll need 6-10 batteries (60-100 kWh) depending on your daily usage. Most homes use 25-45 kWh daily, so multiply by 3 days and add 20% for efficiency losses.
-
How to deal with scrapped lithium iron phosphate batteries
Lithium iron phosphate (LFP) batteries have gained widespread recognition for their exceptional thermal stability, remarkable cycling performance, non-toxic attributes, and cost-effectiveness. However, the increa. ••Thoroughly covers recycling methods, analyze pros/cons and f. Lithium-ion batteries (LIBs), recognized for their exceptional energy storage capabilities, have gained widespread acceptance owing to their high current density, extende. Because the value of the metal in discarded LFP batteries is relatively low compared to other cathode materials, it receives less attention (Bi et al., 2019b; Zhang et al., 2022a). However. Despite the huge benefits of recycling discarded LFP batteries, there are still many challenges in the current LFP recycling industry, which we boil down to the following:. A generalized overview of LFP waste processing is shown in Fig. 6. It includes the process of collecting, pretreatment, recycling or repairing valuable components of waste LFP batt.
[PDF Version]
FAQs about How to deal with scrapped lithium iron phosphate batteries
Are lithium iron phosphate batteries safe?
Lithium iron phosphate (LFP) batteries have gained widespread recognition for their exceptional thermal stability, remarkable cycling performance, non-toxic attributes, and cost-effectiveness. However, the increased adoption of LFP batteries has led to a surge in spent LFP battery disposal.
What is a lithium iron phosphate (LFP) battery?
Integrate technical and non-technical aspects, summarize status and prospect. Lithium iron phosphate (LFP) batteries have gained widespread recognition for their exceptional thermal stability, remarkable cycling performance, non-toxic attributes, and cost-effectiveness.
Why is the recovery of metals from spent lithium ion batteries important?
In recent years, the recovery of metals from spent lithium ion batteries (LIBs) has become increasingly important due to their great environmental impact and the wastage of valuable metallic resources. Among different types of spent LIBs, processing and recycling the spent LiFePO4 batteries are challenging b
Can a high purity lithium ion battery be recycled?
High purity Li 2 CO 3 (99.95 wt%) could be obtained with a high recovery rate. This research demonstrates the possibility of improving the metal recycling effectiveness from spent LiFePO 4 batteries by incorporating the principles of green chemistry and probably contributes to the sustainability of the lithium ion battery industry.
Why are lithium iron phosphate batteries used in electric vehicles?
Lithium iron phosphate (LiFePO 4, LFP) batteries are widely used in electric vehicles (EVs) and hybrid electric vehicles (HEVs) due to its long term cycle performance and high security in recent years [1, 2, 3].
How phosphorus and lithium phosphate can be recycled?
In one approach, lithium, iron, and phosphorus are recovered separately, and produced into corresponding compounds such as lithium carbonate, iron phosphate, etc., to realize the recycling of resources. The other approach involves the repair of LFP material by direct supplementation of elements, and then applying it to LIBs again.
-
How to arrange the wiring of lithium iron phosphate batteries
Battery packs are designed by connecting multiple cells in series; each cell adds its voltage to the battery's terminal voltage. Figure 1 below shows a typical BSLBATT 13.2V LiFePO4 starter battery cell configuration. Parallel Connection connects multiple batteries in parallel; each battery adds its battery capacity to the ports. Batteries may consist of a combination of series and parallel connections. Cells in parallel increased currenthandling; each cell adds to the ampere-hour (Ah) total of the battery The BSLBATT. BSLBATT's 13.2V batteries may be used in series and or parallel to achieve higher operating voltages and or capacities for your specific application. It is important to use the same battery.
[PDF Version]
FAQs about How to arrange the wiring of lithium iron phosphate batteries
How are LiFePO4 batteries connected?
Like other types of battery cells, LiFePO4 (Lithium Iron Phosphate) cells are often connected in parallel and series configurations to meet specific voltage and capacity requirements for various applications. The following is some information about series and parallel connections before we get into the details further.
What is a lithium ion battery in parallel?
Lithium ion batteries in parallelis to increase the amp hours of a battery (i.e. how long the battery will run on a single charge). For example if you connect two of our 12 V, 10 Ah batteries in parallel you will create one battery that has 12 Volts and 20 Amp-hours.
Can a 12V lithium battery be connected in series?
Yes, you can connect 12V lithium batteries in series. When you do, the voltages of each battery will add up. For instance, if you connect two 12V lithium batteries in series, you will get a total voltage of 24V. Can i connect 12v lithium in parallel? Yes, you can connect 12V lithium batteries in parallel.
How do you connect a battery in series?
Keep in mind in series connections each battery needs to have the same voltage and capacity rating, or you can end up damaging the battery. To connect batteries in series, you connect the positive terminal of one battery to the negative of another until the desired voltage is achieved.
Should you mix lithium ion batteries?
Consistent battery performance is essential, and mixing lithium-ion batteries of different brands, capacities, or types should be avoided. Always pay attention to battery polarity to prevent voltage drops or hazards. To effectively expand your battery bank, prompt action is crucial.
How to connect a battery in parallel?
When connecting the batteries in parallel, you should ensure the battery is within 100 millivolts (100mV or 0.1V); if not, there is an increased chance of battery balancing. So, before connecting the batteries, completely charge them individually and check with the voltmeter. The charges to charge the battery must be of slightly higher voltage.
-
How to protect lithium batteries from explosion
How to Protect Against Lithium-Ion Battery Fires: 8 Essential Strategies1. Store Batteries at the Correct Temperature. Implement Regular Maintenance and Inspections.
FAQs about How to protect lithium batteries from explosion
How can you prevent lithium-ion battery fires and explosions?
Preventing lithium-ion battery fires and explosions requires a combination of vigilant maintenance, proper storage and charging practices, and staff education. By adhering to these safety measures, both individuals and businesses can significantly reduce the risks associated with lithium-ion batteries.
Are lithium-ion batteries safe?
Mobile phones, e-cigarettes, laptops, hoverboards and many other electronic devices are powered by lithium-ion batteries. These batteries are normally very safe, but if used improperly then there is a small risk of fire or explosion. Read this article to learn how to handle lithium-ion batteries safely.
How to store lithium ion batteries safely?
Improper storage can heighten the risk of fire. Here's how to store lithium-ion batteries safely: Cool, dry environment: Avoid heat and humidity. High temperatures accelerate the degradation of battery cells. Distance between batteries: Store batteries at least two feet apart to prevent a fire from spreading if one battery malfunctions.
Can a lithium-ion battery fire be extinguished?
In all circumstances, only suitably trained personnel/emergency-responders should attempt to extinguish early-stage lithium-ion battery fires, when it is safe to do so. As lithium-ion battery fires create their own oxygen during thermal runaway, they are very difficult for fire and rescue services to deal with.
What causes a lithium ion battery to explode?
The core of the problem lies in the volatile chemistry of lithium-ion batteries. When the internal components, such as the separator or electrodes, are damaged or malfunction, it can trigger a thermal runaway —a rapid and uncontrollable increase in temperature that often results in fire or explosion.
How do you manage a lithium-ion battery hazard?
Specific risk control measures should be determined through site, task and activity risk assessments, with the handling of and work on batteries clearly changing the risk profile. Considerations include: Segregation of charging and any areas where work on or handling of lithium-ion batteries is undertaken.
-
The materials used to make small lithium batteries are
Key materials include lithium, cobalt, nickel, manganese, and graphite, often sourced from specific regions globally:Lithium: Predominantly mined in Australia and South America. Cobalt: Mainly sourced from the Democratic Republic of Congo. Nickel & Manganese: Mined in various countries including Indonesia and China.
FAQs about The materials used to make small lithium batteries are
How a lithium battery is made?
1. Extraction and preparation of raw materials The first step in the manufacturing of lithium batteries is extracting the raw materials. Lithium-ion batteries use raw materials to produce components critical for the battery to function properly.
What materials are used in lithium ion batteries?
The materials used in these batteries determine how lightweight, efficient, durable, and reliable they will be. A lithium-ion battery typically consists of a cathode made from an oxide or salt (like phosphate) containing lithium ions, an electrolyte (a solution containing soluble lithium salts), and a negative electrode (often graphite).
What element makes a lithium battery a battery?
This element serves as the active material in the battery's electrodes, enabling the movement of ions to produce electrical energy. What metals makeup lithium batteries? Lithium batteries primarily consist of lithium, commonly paired with other metals such as cobalt, manganese, nickel, and iron in various combinations to form the cathode and anode.
What is a lithium ion battery?
Lithium-ion batteries are electromechanical rechargeable batteries, widely used to power vehicles or portable electronics. These batteries contain an electrolyte made of lithium salt along with electrodes. The lithium ions pass through the electrolyte from the anode to the cathode to make the battery work.
Where does lithium come from in a battery?
Lithium may be the key component in most modern batteries, but it doesn't make up the bulk of the material used in them. Instead, much of the material is in the electrodes, where the lithium gets stored when the battery isn't charging or discharging.
How can lithium-ion batteries be made more compact?
So one way to make lighter and more compact lithium-ion batteries is to find electrode materials that can store more lithium. That's one of the reasons that recent generations of batteries are starting to incorporate silicon into the electrode materials. There are materials that can store even more lithium than silicon; a notable example is sulfur.
-
How to maintain solar lead-acid batteries
While it's perfectly fine to string together a few batteries to increase your storage capacity, make an effort to keep the number of batteries in your bank as low as possible. The general guideline is to make sure you have enough storage for five days' worth of power. While it may be tempting to add capacity beyond that,. The batteries in your bank need to be rotated within the circuit on a regular basis in order to provide the maximum effective lifespan. Because of the possibility of uneven charging,. Most of the deep cycles batteries that are used for solar storage require water in their cells to keep them in optimal working order. While some tout. Another common mistake made with solar batteries that can cut their lifespan short is allowing them to become completely discharged and failing to recharge them for long periods of time. When batteries reach a nearly full charge, they can begin a phenomenon known as gassing or boiling. While that may sound disconcerting, gassing is a normal part of the battery usage and is actually good for a battery. It should occur.
[PDF Version]
-
Differences between the nine batteries in a solar battery cabinet lithium battery pack
In this article, we will compare different lithium battery types for solar energy storage systems, helping you make an informed choice based on yourIn this article, we will compare different lithium battery types for solar energy storage systems, helping you make an informed choice based on your.
-
How many batteries should be connected in parallel for the base station power supply
The basic concept is that when connecting in parallel, you add the amp hour ratings of the batteries together, but the voltage remains the same. For example: 1. two 6 volt 4.5 Ah batteries wired in parallel are capable of providing 6 volt 9 amp hours (4.5 Ah + 4.5 Ah). 2. four 1.2 volt 2,000 mAh wired in parallel can provide 1.2. This is the big “no go area”. The battery with the higher voltage will attempt to charge the battery with the lower voltage to create a balance in the. This is possible and won't cause any major issues, but it is important to note some potential issues: 1. Check your battery chemistries – Sealed Lead Acid batteries for example have different charge points than flooded lead acid units. This means that if recharging the two.
[PDF Version]
FAQs about How many batteries should be connected in parallel for the base station power supply
How to wire multiple batteries in parallel?
To wire multiple batteries in parallel, connect the negative terminal (-) of one battery to the negative terminal (-) of another, and do the same to the positive terminals (+). For example, you can connect four Renogy 12V 200Ah Core Series LiFePO4 Batteries in parallel. In this system, the system voltage and current are calculated as follows:
What happens if a battery is connected in parallel?
When batteries are connected in parallel, the voltage across each battery remains the same. For instance, if two 6-volt batteries are connected in parallel, the total voltage across the batteries would still be 6 volts. Effects of Parallel Connections on Current
What is the capacity of a battery bank wired in parallel?
Capacity Calculation: The overall capacity of a battery bank wired in parallel is the sum of the individual battery capacities. For example, if you have four 100Ah batteries wired in parallel, the total capacity would be 400Ah. 3. Voltage Compatibility: When connecting batteries in parallel, their voltages should be identical.
What is a parallel battery configuration?
In parallel connection, the positive terminal of one battery is connected to the positive terminal of another, and the negative terminal of one battery is connected to the negative terminal of another. This results in a combined battery bank with increased capacity. Advantages of Parallel Battery Configuration:
Should 12V batteries be connected in series or parallel?
Connecting 12V batteries in series will increase the voltage of the battery bank while keeping the amp-hour capacity the same. Connecting 12V batteries in parallel will increase the amp-hour capacity of the battery bank while keeping the voltage the same.
What is the difference between a series and a parallel battery?
In a series configuration, batteries are connected end-to-end, resulting in increased voltage while the capacity remains the same. On the other hand, parallel connections combine batteries side by side, maintaining the voltage but increasing the overall capacity. Does connecting batteries in series affect their lifespan?
-
Safety of transporting lithium batteries
When handling lithium-ion batteries, safety precautions are a must:1. Cracks, dents, or leaks should be treated as warning signs. Avoid exposing batteries to heat or fire.
FAQs about Safety of transporting lithium batteries
Are lithium batteries safe to transport?
As a result, batteries are manufactured and shipped globally, and the safe and reliable transport of batteries from production sites to suppliers and consumers, as well as for disposal, must be guaranteed at all times. This is especially true of lithium batteries, which have been identified as dangerous goods when they are transported.
Are lithium batteries regulated in transportation?
The HMR apply to any material DOT determines can pose an unreasonable risk to health, safety, and property when transported in commerce. Lithium batteries must conform to all applicable HMR requirements when offered for transportation or transported by air, highway, rail, or water. Why
Why is regulatory compliance important when transporting lithium batteries?
Ensuring regulatory compliance when transporting lithium batteries is crucial for mitigating safety risks and avoiding legal issues. Lithium batteries, while essential in powering modern devices, present significant challenges due to their chemical composition and potential hazards.
What are the regulations for lithium batteries?
International, national, and regional governments, as well as other authorities, have developed regulations for air, road, rail, and sea transportation of lithium batteries and the products that incorporate these batteries. The regulations govern conduct, actions, procedures, and arrangements.
Are lithium ion batteries dangerous?
Lithium ion batteries with a nominal capacity exceeding 100 Wh and lithium metal batteries containing over 2g of lithium are classed as dangerous goods (Class 9), as such there are strict requirements for transporting them via road, air, sea and rail. Simplified requirements apply for other lithium batteries that do not reach these thresholds.
Can a road transport unit carry lithium batteries?
In addition, the passage of a road transport unit carrying lithium batteries is forbidden in category E road tunnels, which are assigned by the competent authority and indicated by a sign with an additional panel bearing a letter E.
-
How to divide lead-acid batteries into several power strings
The single-cell configuration is the simplest battery pack; the cell does not need matching and the protection circuit on a small Li-ion cell can be kept simple. Typical examples are mobile phones and tablets with o. Portable equipment needing higher voltages use battery packs with two or more cells connected in series. Figure 2 shows a battery pack with four 3.6V Li-ion cells in series, al. There is a common practice to tap into the series string of a lead acid array to obtain a lower voltage. Heavy duty equipment running on a 24V battery bank may need a 12V supply for a. If higher currents are needed and larger cells are not available or do not fit the design constraint, one or more cells can be connected in parallel. Most battery chemistries allo. The series/parallel configuration shown in Figure 6 enables design flexibility and achieves the desired voltage and current ratings with a standard cell size. The total power is the su.
[PDF Version]
FAQs about How to divide lead-acid batteries into several power strings
What is a battery string?
Similar to PV, groups of batteries connected in parallel are called a Battery String. As for the capacity rating of a battery bank, it is similar to the current principle. When connecting batteries in series, the capacity is not added. As for a parallel connection, the capacities add up.
What is the voltage level of a lead acid battery?
Lead-acid batteries are usually rated at 12 V, 24 V or 48 V. This voltage is determined by the series and parallel interconnection of several batteries. The voltage needs to meet the load or inverter voltage level requirements. How do we determine the battery bank voltage levels for PV applications?
How many lead acid cells are in a 12V starter battery?
The car industry wanted to increase the starter battery from 12V (14V) to 36V, better known as 42V, by placing 18 lead acid cells in series. Logistics of changing the electrical components and arcing problems on mechanical switches derailed the move.
How to arrange batteries to increase voltage or gain higher capacity?
Learn how to arrange batteries to increase voltage or gain higher capacity. Batteries achieve the desired operating voltage by connecting several cells in series; each cell adds its voltage potential to derive at the total terminal voltage. Parallel connection attains higher capacity by adding up the total ampere-hour (Ah).
How many volts does a 6 cell lead acid string produce?
In comparison, a six-cell lead acid string with 2V/cell will generate 12V, and four alkaline with 1.5V/cell will give 6V. Figure 2: Series connection of four cells (4s).
How do batteries achieve a desired operating voltage?
Batteries achieve the desired operating voltage by connecting several cells in series; each cell adds its voltage potential to derive at the total terminal voltage. Parallel connection attains higher capacity by adding up the total ampere-hour (Ah). Some packs may consist of a combination of series and parallel connections.
-
How to distinguish the quality of refurbished lead-acid batteries
Determining whether a lead-acid battery is refurbished can be challenging, but there are several signs and tests you can perform to help you make an informed judgment.
FAQs about How to distinguish the quality of refurbished lead-acid batteries
Is a lead-acid battery a good battery?
Batteries delivering above 80% are generally still in good condition, though they should be monitored for any decline. Capacity testing is one of the most reliable methods for evaluating the true health of a lead-acid battery. However, it can be time-consuming, as the battery must be fully discharged and then recharged. 3.
How do I distinguish between good and bad 12V lead acid batteries?
The difference, or drop, in voltage is IR, is due to internal resistance of battery. We now have current and voltage drop, so internal resistance can be calculated. How do I distinguish between good and bad 12V lead acid batteries with the internal resistance value? If IR>30 milliohm, battery is in very bad condition. Probably unusable.
Why do you need a lead-acid battery test?
Impedance Testing: Comprehensive Health Assessment Lead-acid batteries degrade over time due to several factors, including sulfation, temperature fluctuations, and improper maintenance. Testing these batteries at regular intervals allows us to detect potential problems early, ensuring longevity and optimal performance.
What is the internal resistance of a lead-acid battery?
The internal resistance of a lead-acid battery can provide insights into potential problems such as sulfation, a common cause of battery failure. High internal resistance can indicate that the battery is nearing the end of its life or has been poorly maintained.
How do you test a lead-acid battery?
Lead-acid batteries are highly sensitive to temperature. Testing should ideally be conducted at room temperature to ensure accurate results. Extremely high or low temperatures can skew the results of voltage, capacity, and resistance tests. To ensure optimal performance, it is recommended to perform battery testing at regular intervals.
How do I know if a battery is a good battery?
If the battery lights the lamp and the terminal voltage stays above 5.8V or so (assuming a ~500mA load), you're probably OK given the caveats about not using marginal batteries in important applications. Measure the time you can have a 6 V say 10 W lamp connected before you hit 6 or 6.1 V. This will give you the useful Ah of the battery.