12V 7Ah Solar Light Battery. 12v 7ah battery lithium

Battery Charge Time Calculator

Use our battery charge time calculator to easily estimate how long it’ll take to fully charge your battery.

Battery Charge Time Calculator

Tip: If you’re solar charging your battery, you can estimate its charge time much more accurately with our solar battery charge time calculator.

How to Use This Calculator

Enter your battery capacity and select its units from the list. The unit options are milliamp hours (mAh), amp hours (Ah), watt hours (Wh), and kilowatt hours (kWh).

Enter your battery charger’s charge current and select its units from the list. The unit options are milliamps (mA), amps (A), and watts (W).

If the calculator asks for it, enter your battery voltage or charge voltage. Depending on the combination of units you selected for your battery capacity and charge current, the calculator may ask you to input a voltage.

Select your battery type from the list.

Optional: Enter your battery state of charge as a percentage. For instance, if your battery is 20% charged, you’d enter the number 20. If your battery is dead, you’d enter 0.

Click Calculate Charge Time to get your results.

Battery Charging Time Calculation Formulas

For those interested in the underlying math, here are 3 formulas to for calculating battery charging time. I start with the simplest and least accurate formula and end with the most complex but most accurate.

Formula 1

Formula: charge time = battery capacity ÷ charge current

Accuracy: Lowest

Complexity: Lowest

The easiest but least accurate way to estimate charge time is to divide battery capacity by charge current.

Most often, your battery’s capacity will be given in amp hours (Ah), and your charger’s charge current will be given in amps (A). So you’ll often see this formula written with these units:

charge time = battery capacity (Ah) ÷ charge current (A)

However, battery capacity can also be expressed in milliamp hours (mAh), watt hours (Wh) and kilowatt hours (kWh). And your battery charger may tell you its power output in milliamps (mA) or watts (W) rather than amps. So you may also see the formula written with different unit combinations.

charge time = battery capacity (mAh) ÷ charge current (mA) charge time = battery capacity (Wh) ÷ charge rate (W)

And sometimes, your units are mismatched. Your battery capacity may be given in watt hours and your charge rate in amps. Or they may be given in milliamp hours and watts.

In these cases, you need to convert the units until you have a ‘matching’ pair.- such as amp hours and amps, watt hours and watts, or milliamp hours and milliamps.

For reference, here are the formulas you need to convert between the most common units for battery capacity and charge rate. Most of them link to our relevant conversion calculator.

Battery capacity unit conversions:

• watt hours = amp hours × volts
• amp hours = watt hours ÷ volts
• milliamp hours = amp hours × 1000
• amp hours = milliamp hours ÷ 1000
• watt hours = milliamp hours × volts ÷ 1000
• milliamp hours = watt hours ÷ volts × 1000
• kilowatt hours = amp hours × volts ÷ 1000
• amp hours = kilowatt hours ÷ volts × 1000
• watt hours = kilowatt hours × 1000
• kilowatt hours = watt hours ÷ 1000

Charge rate unit conversions:

The formula itself is simple, but taking into account all the possible conversions can get a little overwhelming. So let’s run through a few examples.

Example 1: Battery Capacity in Amp Hours, Charging Current in Amps

Let’s say you have the following setup:

• Battery capacity: 100 amp hours
• Charging current: 10 amps

To calculate charging time using this formula, you simply divide battery capacity by charging current.

In this scenario, your estimated charge time is 10 hours.

Example 2: Battery Capacity in Watt Hours, Charging Rate in Watts

Let’s now consider this scenario:

Because your units are again ‘matching’, to calculate charging time you again simply divide battery capacity by charging rate.

In this scenario, your estimated charge time is 8 hours.

Example 3: Battery Capacity in Milliamp Hours, Charging Rate in Watts

Let’s consider the following scenario where the units are mismatched.

First, you need to decide which set of matching units you want to convert to. You consider watt hours for battery capacity and watts for charge rate. But you’re unable to find the battery’s voltage, which you need to convert milliamp hours to watt hours.

You know the charger’s output voltage is 5 volts, so you settle on amp hours for battery capacity and amps for charge rate.

With that decided, you first divide watts by volts to get your charging current in amps.

Next, you convert battery capacity from milliamp hours to amp hours by dividing milliamp hours by 1000.

Now you have your battery capacity and charging current in ‘matching’ units. Finally, you divide battery capacity by charging current to get charge time.

In this example, your estimated battery charging time is 1.5 hours.

Formula 2

Formula: charge time = battery capacity ÷ (charge current × charge efficiency)

Accuracy: Medium

Complexity: Medium

No battery charges and discharges with 100% efficiency. Some of the energy will be lost due to inefficiencies during the charging process.

This formula builds on the previous one by factoring in charge/discharge efficiency, which differs based on battery type.

Here are efficiency ranges of the main types of rechargeable batteries (source):

Note: Real-world charge efficiency is not fixed and varies throughout the charging process based on a number of factors, including charge rate and battery state of charge. The faster the charge, typically the less efficient it is.

Example 1: Lead Acid Battery

Let’s assume you have the following setup:

To calculate charging time using Formula 2, first you must pick a charge efficiency value for your battery. Lead acid batteries typically have energy efficiencies of around 80-85%. You’re charging your battery at 0.1C rate, which isn’t that fast, so you assume the efficiency will be around 85%.

With an efficiency percentage picked, you just need to plug the values in to the formula.

100Ah ÷ (10A × 85%) = 100Ah ÷ 8.5A = 11.76 hrs

In this example, your estimated charge time is 11.76 hours.

Recall, that, using Formula 1, we estimated the charge time for this setup to be 10 hours. Just by taking into account charge efficiency our time estimate increased by nearly 2 hours.

Example 2: LiFePO4 Battery

Let’s assume you again have the following setup:

Based on your battery being a lithium battery and the charge rate being relatively slow, you assume a charge efficiency of 95%. With that, you can plug your values into Formula 2.

1200Wh ÷ (150W × 95%) = 1200Wh ÷ 142.5W = 8.42 hrs

In this example, your estimated charge time is 8.42 hours.

Using Formula 1, we estimated this same setup to have a charge time of 8 hours. Because lithium batteries are more efficient, factoring in charge efficiency doesn’t affect our estimate as much as it did with a lead acid battery.

Example 3: Lithium Ion Battery

Again, let’s revisit the same setup as before:

First, you need to assume a charge efficiency. Based on the battery being a lithium battery and the charge rate being relatively fast, you assume the charge efficiency is 90%.

As before, you need to ‘match’ units, so you first convert the charging current to amps.

Then you convert the battery’s capacity from milliamp hours to amp hours.

With similar units, you can now plug everything into the formula to calculate charge time.

3Ah ÷ (2A × 90%) = 3Ah ÷ 1.8A = 1.67 hours

In this example, your estimated charge time is 1.67 hours.

Formula 3

Formula: charge time = (battery capacity × depth of discharge) ÷ (charge current × charge efficiency)

Accuracy: Highest

Complexity: Highest

The 2 formulas above assume that your battery is completely dead. In technical terms, this is expressed by saying the battery is at 100% depth of discharge (DoD). You can also describe it as 0% state of charge (SoC).

Formula 3 incorporates DoD to let you estimate charging time regardless of how charged your battery is.

Example 1: 50% DoD

Let’s revisit this setup, but this time assume our lead acid battery has a 50% DoD. (Most lead acid batteries should only be discharged to 50% at most to preserve battery life.)

As before, let’s assume a charging efficiency of 85%.

We have all the info we need, so we just plug the numbers into Formula 3.

(100Ah × 50%) ÷ (10A × 85%) = 50Ah ÷ 8.5A = 5.88 hrs

In this example, your battery’s estimated charge time is 5.88 hours.

Example 2: 80% DoD

For this example, imagine you have the following setup:

As before, we’ll assume that the charging efficiency is 95%.

With that in mind, here’s the calculation you’d do to calculate charge time.

(1200Wh × 80%) ÷ (150W × 95%) = 960Wh ÷ 142.5W = 6.74 hrs

In this example, it will take about 6.7 hours to fully charge your battery from 80% DoD.

Example 3: 95% DoD

Let’s say your phone battery is at 5%, meaning it’s at a 95% depth of discharge. And your phone battery and charger have the following specs:

As before, we need to convert capacity and charge rate to similar units. Let’s first convert battery capacity to amp hours.

Next, let’s convert charge current to amps.

Because the charge C-rate is relatively high, we’ll again assume a charging efficiency of 90% and then plug everything into Formula 3.

(3Ah × 95%) ÷ (2A × 90%) = 2.85Ah ÷ 1.8A = 1.58 hrs

Your phone battery will take about 1.6 hours to charge from 5% to full.

Why None of These Formulas Is Perfectly Accurate

None of these battery charge time formulas captures the real-life complexity of battery charging. Here are some more factors that affect charging time:

• Your battery may be powering something. If it is, some of the charge current will be siphoned off to continue powering that device. The more power the device is using, the longer it will take for your battery to charge fully.
• Battery chargers aren’t always outputting their max charge rate. Many battery chargers employ charging algorithms that adjust the charging current and voltage based on how charged the battery is. For example, some battery chargers slow the charge rate down drastically once the battery reaches around 70-80% charged. These charging algorithms vary based on charger and battery type.
• Batteries lose capacity as they age. An older battery will have less capacity than an identical new battery. Your 100Ah LiFePO4 battery may have only have around 85Ah capacity after 1000 cycles. And the rates at which batteries age depend on a number of factors.
• Lithium batteries have a Battery Management System (BMS). Besides consuming a modest amount of power, the BMS can adjust the charging current to protect the battery and optimize its lifespan. iPhones have a feature called Optimized Battery Charging that delays charging the phone’s battery past 80% until you need to use it.
• Lead acid battery chargers usually have a timed absorption stage. After being charged to around 70-80%, many lead acid battery chargers (and solar charge controllers) enter a timed absorption stage for the remainder of the charge cycle that is necessary for the health of the battery. It’s usually a fixed 2-3 hours, regardless of how big your battery is, or how fast your charger.

In short, batteries are wildly complex, and accurately calculating battery charge time is no easy task. It goes without saying that any charge time you calculate using the above formulas.- or our battery charge time calculator.- should be viewed as an estimate.

V 7Ah Solar Light Battery

Model Number: MLP1207S1 2. Nominal Capacity: 7Ah 3. Nominal Voltage: 12.8V 4. MAX Charge Voltage: 14.6V 5. MAX Charge Current: 3.5A 6. Customization Support: Including voltage, capacity, current, size, appearance, etc.

Light in weight:

LiFePO4 substitution battery is only approx. 1/3 of lead acid battery in weight;

Environmentally friendly:

LiFePO4 does not contain any harmful heavy metal elements, pollution-free both in production and actual use.

Long Cycle Life:

This battery is with over 2000 time charge and discharge cycle life, after that, capacity left is still 80% of original value, self discharge rate is much lower than li-ion battery and lead-acid battery;

Customized Save Time:

Battery cells, size, capacity, voltage, connector…most parameters can be changed according to your request. You don’t need to take too much time to search an exist model

Application

1)Energy Storage: PV Energy Storage, UPS, backup, power station; 2)EV: Golf trolleys, Electric scooters; 3)Solar System: Solar Home System, Solar Street Light, Solar CCTV 4)Telecommunications Base Stations; 5)Others: Emergency Light, Miner’s lamp, portable power supply, digital products, Roboticsetc, AGV/RGV/AMR, etc.

Features:

• Maintenance-free operation;
• The long service life of 10~15 years;
• Inbuilt BMS multiple security protection;
• High-quality lithium iron phosphate batteries, safe and reliable;
• rechargeable time, longer lifetime, economic and environmental protection.

Specification:

• 36 months longer warranty time
• OEM/ODM custom is acceptable without MOQ Request
• Made of industrial Grade original MANLY factory lifepo4 battery cell with Factory price
• With advanced Smart BMS (Battery Management System)

Packing Delivery:

1) Carton box.pallet-container.

2) Packaging also can be customized by customers’ requirements.

1) Shipping time for news sample is 25-30 working days; mass production is 15~20 working days – since deposit received and samples confirmed.

2) Sample order is supposed to be shipped by DHL, UPS, FedEx, or TNT, mass order is suggested to ship by sea, we could supply forwarder service if you need.

Our Services:

OEM ODM can customize according to your request :

• Battery voltage, capacity, and dimension.
• BMS charging and discharging current.
• Connector, case, and wire.
• Your own logo eg: silk print.

After-sales service is available :

• Respond in 24 hours to any inquiry on our product.
• Take action quickly for a normal customers’ claim within 12 hours.
• Good after-sales service: We offer 3 years quality warranty for lifepo4 batteries 12.8V 20Ah/50Ah/100Ah/200Ah/500Ah/1000Ah/…
• One by one tested before shipment.

1: Is MANLY Battery a trading company or factory?

R: MANLY is a company with its own factory, which integrates research, development, production, and sales.

2:How about is the quality of MANLY’s LiFePo4 Battery product?

R: MANLY has 12 years of experience in lifepo4 battery, is also the authorized supplier of Siemens and Bosch.

3: Can you do OEM/ODM project?

R: Yes, we have engineers who can help you design and RD any related products.

4: What’s your MOQ?

R: According to your battery voltage and capacity.

5: What payment terms we can accept?

Remark: Our products are customized, so the main data can be changed by customer’s requirements.

Dakota Lithium 12v 7ah Deep Cycle Battery

Built Dakota tough and crafted out of Lithium Iron Phosphate (LiFePO4) technology this is a battery built.

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Dakota Lithium 12v 7ah Deep Cycle Battery

Decrease quantity for Dakota Lithium 12v 7ah Deep Cycle Battery Increase quantity for Dakota Lithium 12v 7ah Deep Cycle Battery

Dakota Lithium 12v 7ah Deep Cycle Battery

Built Dakota tough and crafted out of Lithium Iron Phosphate (LiFePO4) technology this is a battery built to last. With a lifespan of 2,000 charge cycles this battery will last up to 5 times longer than your typical SLA battery while providing 100% more capacity at 60% less weight. Rated at 7 Ampere Hours (Ah), this is our smallest and lightest battery. Ideal for industrial purposes where you need a long lifespan battery that charges quickly, or for outdoor uses where weight is at a premium. LiFePO4 charger recommended for optimal performance.

SPECIFICATIONS

World beating, best in class, eleven year manufacturer defect warranty.

5.94x 2.55x 3.74 (151x65x95mm). Replaces UB1280 battery and many others.

2lbs 2oz (1.30Kg). That’s 60% lighter then a SLA battery.

7 ampere hours. Dakota Lithium batteries provide consistent power for all 7 amp hours. DL LiFePO4 batteries have a flat voltage curve, which means they have a steady power output as the battery discharges. The power output will not dramatically drop like similar sized SLA batteries. You get all the juice down to the last drop.

Up to 80% capacity for 2,000 cycles in recommended conditions. The typical SLA has 500 cycles. Dakota Lithium batteries last so long that the price per use is a fraction of traditional batteries.

Ideal for rugged harsh environments. Much better than SLA or other lithium’s20’F min, 120’F max optimal operating temps (battery performs well down to.20’F). Avoid charging below 32’F.

Standard F2 terminals (6.35mm or 0.25 wide)

10 A max continuous, 50 A max 300 mS pulse. 9.0 V max discharge, 11.0 V max recommended discharge. For longest lifetime recommended discharge rate 1-5 Amps. The flat discharge voltage curve provides a 75% bigger capacity then a SLA 10Ah battery.

10 A max, 14 V max recommended, 15 V max. Please note: this battery should be charged using a LiFePO4 compatible charger. A SLA charger may work, but will reduce performance and lifespan of the battery.

Contains a circuit that handles cell balancing, low voltage cutoff, high voltage cutoff, short circuit protection and high temperature protection for increased performance and longer life.

All batteries are UN 38 certified. Dakota Lithium’s cells are UL1642 certified and have been tested per IEC62133 standards. Meets all US International regulations for air, ground, and train transport.

This battery should be charged using a LiFePO4 compatible charger. A SLA charger may work, but will reduce performance and lifespan of the battery.

The Complete Guide to Lithium vs Lead Acid Batteries

When it comes to choosing the right battery for your application, you likely have a list of conditions you need to fulfill. How much voltage is needed, what is the capacity requirement, cyclic or standby, etc.

Once you have the specifics narrowed down you may be wondering, “do I need a lithium battery or a traditional sealed lead acid battery?” Or, more importantly, “what is the difference between lithium and sealed lead acid?” There are several factors to consider before choosing a battery chemistry, as both have strengths and weaknesses.

For the purpose of this blog, lithium refers to Lithium Iron Phosphate (LiFePO4) batteries only, and SLA refers to lead acid/sealed lead acid batteries.

CYCLIC PERFORMANCE LITHIUM VS SLA

The most notable difference between lithium iron phosphate and lead acid is the fact that the lithium battery capacity is independent of the discharge rate. The figure below compares the actual capacity as a percentage of the rated capacity of the battery versus the discharge rate as expressed by C (C equals the discharge current divided by the capacity rating). With very high discharge rates, for instance.8C, the capacity of the lead acid battery is only 60% of the rated capacity. Find out more about C rates of batteries.

Therefore, in cyclic applications where the discharge rate is often greater than 0.1C, a lower rated lithium battery will often have a higher actual capacity than the comparable lead acid battery. This means that at the same capacity rating, the lithium will cost more, but you can use a lower capacity lithium for the same application at a lower price. The cost of ownership when you consider the cycle, further increases the value of the lithium battery when compared to a lead acid battery.

The second most notable difference between SLA and Lithium is the cyclic performance of lithium. Lithium has ten times the cycle life of SLA under most conditions. This brings the cost per cycle of lithium lower than SLA, meaning you will have to replace a lithium battery less often than SLA in a cyclic application.

CONSTANT POWER DELIVERY LITHIUM VS LEAD ACID

Lithium delivers the same amount of power throughout the entire discharge cycle, whereas an SLA’s power delivery starts out strong, but dissipates. The constant power advantage of lithium is shown in the graph below which shows voltage versus the state of charge.

A lithium battery as shown in the orange has a constant voltage as it discharges throughout the entire discharge. Power is a function of voltage times current. The current demand will be constant and thus the power delivered, power times current, will be constant. So, let’s put this in a real-life example.

Have you ever turned on a flashlight and noticed it’s dimmer than the last time you turned it on? This is because the battery inside the flashlight is dying, but not yet completely dead. It is giving off a little power, but not enough to fully illuminate the bulb.

If this were a lithium battery, the bulb would be just as bright from the beginning of its life to the end. Instead of waning, the bulb would just not turn on at all if the battery were dead.

CHARGING TIMES OF LITHIUM AND SLA

Charging SLA batteries is notoriously slow. In most cyclic applications, you need to have extra SLA batteries available so you can still use your application while the other battery is charging. In standby applications, an SLA battery must be kept on a float charge.

With lithium batteries, charging is four times faster than SLA. The faster charging means there is more time the battery is in use, and therefore requires less batteries. They also recover quickly after an event (like in a backup or standby application). As a bonus, there is no need to keep lithium on a float charge for storage. For more information on how to charge a lithium battery, please view our Lithium Charging Guide.

HIGH TEMPERATURE BATTERY PERFORMANCE

Lithium’s performance is far superior than SLA in high temperature applications. In fact, lithium at 55°C still has twice the cycle life as SLA does at room temperature. Lithium will outperform lead under most conditions but is especially strong at elevated temperatures.

COLD TEMPERATURE BATTERY PERFORMANCE

Cold temperatures can cause significant capacity reduction for all battery chemistries. Knowing this, there are two things to consider when evaluating a battery for cold temperature use: charging and discharging. A lithium battery will not accept a charge at a low temperature (below 32° F). However, an SLA can accept low current charges at a low temperature.

Conversely, a lithium battery has a higher discharge capacity at cold temperatures than SLA. This means that lithium batteries do not have to be over designed for cold temperatures, but charging could be a limiting factor. At 0°F, lithium is discharged at 70% of its rated capacity, but SLA is at 45%.

One thing to consider in cold temperature is the state of the lithium battery when you want to charge it. If the battery has just finished discharging, the battery will have generated enough heat to accept a charge. If the battery has had a chance to cool down, it may not accept a charge if the temperature is below 32°F.

BATTERY INSTALLATION

If you have ever tried to install a lead acid battery, you know how important it is to not install it in an invert position to prevent any potential issues with venting. While an SLA is designed to not leak, the vents allow for some residual release of the gasses.

In a lithium battery design, the cells are all individually sealed and cannot leak. This means there is no restriction in the installation orientation of a lithium battery. It can be installed on its side, upside down, or standing up with no issues.

BATTERY WEIGHT COMPARISION

Lithium, on average, is 55% lighter than SLA. In cycling applications, this is especially important when the battery is being installed in a mobile application (batteries for motorcycles, scooters or electric vehicles), or where weight may impact the performance (like in robotics). For standby use, weight is an important consideration in remote applications (solar fields) and where installation is difficult (up high in emergency lighting systems, for example).

SLA VS LITHIUM BATTERY STORAGE

Lithium should not be stored at 100% State of Charge (SOC), whereas SLA needs to be stored at 100%. This is because the self-discharge rate of an SLA battery is 5 times or greater than that of a lithium battery. In fact, many customers will maintain a lead acid battery in storage with a trickle charger to continuously keep the battery at 100% so that the battery life does not decrease due to storage.

SERIES PARALLEL BATTERY INSTALLATION

A quick and important note: When installing batteries in series and parallel, it is important that they are matched across all factors including capacity, voltage, resistance, state of charge, and chemistry. SLA and lithium batteries cannot be used together in the same string.

Since an SLA battery is considered a “dumb” battery in comparison to lithium (which has a circuit board that monitors and protects the battery), it can handle many more batteries in a string than lithium.

The string length of lithium is limited by the components on the circuit board. Circuit board components can have current and voltage limitations that long series strings will exceed. For example, a series string of four lithium batteries will have a max voltage of 51.2 volts. A second factor is the protection of the batteries. One battery that exceeds the protection limits can disrupt the charging and discharging of the entire string of batteries. Most lithium strings are limited to 6 or less (model dependent), but higher string lengths can be reached with additional engineering.

There are many differences between SLA and lithium battery performance. In most instances, lithium is the stronger battery. However, SLA should not be discounted as it still has an edge over lithium in some applications, like long strings, extremely high rate of discharge, and cold temperature charging. If there is an application not covered above, or if you have additional questions, please feel free to contact us.

COMPLETE GUIDE ON CONNECTING BATTERIES IN SERIES AND PARALLEL

We have put together a detailed visual guide on how to connect batteries in series, parallel and series-parallel.

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Quality

Manufactured using the latest technology and stringent quality control, our battery products are designed to exceed in performance and reliability.

Experience

Our focused approach to exceptional end to end customer experience sets us apart from the competition. From enquiry to delivery and everything in-between we regularly exceed our customers’ expectations.

Service

Delivery on time, every time to customer specifications. We pride ourselves on offering tailored service solutions to meet our customers’ exact specifications.