A Complete Guide About Solar Panel Installation. Step by Step Procedure with…

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)

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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.

Complete Solar Panel Installation Design Calculations with Solved Examples – Step by Step Procedure

Below is a DIY (do it yourself) complete note on Solar Panel design installation, calculation about No of solar panels, batteries rating / backup time, inverter/UPS rating, load and required power in Watts. with Circuit, wiring diagrams and solved examples. Anyone who follows the simple steps (DIY tutorial) below can install and connect solar panels in home for residential applications.

If you pick this article related to solar panel installation, You will be able to;

  • To calculate the no of solar panel (with rating)
  • To calculate the rating of Solar panel
  • To calculate the rating of batteries for Solar panel system
  • To calculate the back up time of batteries
  • To calculate the required and charging current for batteries
  • To calculate the charging time for batteries
  • To calculate the rating of charge controller
  • How much watt solar panel we need?
  • Connect Solar Panel in Series or Parallel?
  • How to select the proper solar panel for home
  • UPS / Inverter Rating for load requirement and much more…

Solar Panel Installation: Step by Step Procedure with calculation and examples

Before we start, its recommended to read the article about proper selection different types of solar panels and photovoltaic panel for home commercial use as well. To the point, lets know how to wire and install a solar panel system according to the proper calculation and load requirements.

Suppose, we are going to install a solar power system in our home for a total load of 800W where the required backup time of battery is 3 hours (You may use it your own as it is just for sample calculation)

Load = 800 Watts

Required Backup time for batteries = 3 Hours

  • Inverter / UPS Rating =?
  • No of batteries for backup power =?
  • Backup Hours of batteries =?
  • Series or Parallel Connection of Batteries = ?
  • Charging Current for Batteries = ?
  • Charging Time for batteries = ?
  • Required No of Solar Panel =?
  • Series or Parallel Connection of Solar Panels = ?
  • Rating of Charge Controller = ?

Inverter / UPS Rating:

Inverter / UPS rating should be greater than 25% of the total load (for the future load as well as taking losses in consideration)

800 x (25/100) = 200W

Our Load 25% Extra Power = 800200 = 1000 Watts

This is the rating of the UPS (Inverter) i.e. We need 1000W UPS / Inverter for solar panel installation according to our need (based on calculations)

Required No of Batteries

Now the required Back up Time of batteries in Hours = 3 Hours

Suppose we are going to install 100Ah, 12 V batteries,

Now for one Battery (i.e. the Backup time of one battery)

But our required Backup time is 3 Hours.

Therefore, 3/1.5 = 2 → i.e. we will have to connect two (2) batteries each of 100Ah, 12V.

Backup Hours of Batteries

If the number of batteries are given, and you want to know the Backup Time for these given batteries, then use this formula to calculate the backup hours of batteries.

1200 Wh x 2 Batteries = 2400 Wh

2400 Wh / 800 W = 3 hours.

In the first scenario, we will use 12V inverter system, therefore, we will have to connect two (2) batteries (each of 12V, 100 Ah) in Parallel. But a question raised below:

Why Batteries in Parallel, not in Series?

Because this is a 12V inverter System, so if we connect these batteries in series instead of parallel, then the rating of batteries become V1 V2 = 12V 12V = 24V while the current rating would be same i.e.100Ah.

Good to Know: In Series Circuits, Current is same in each wire or section while voltage is different i.e. Voltage are additive e.g. V1V2V3….Vn.

That’s why we will connect the batteries in parallel, because the Voltage of batteries (12 V) remains same, while its Ah (Ampere Hour) rating will be increased. i.e. the system would become = 12V and 100Ah 100Ah = 200Ah.

Good to Know: In parallel Connection, Voltage will be same in each wire or section, while current will be different i.e current is additive e.g. I1I2I3…In

We will now connect 2 batteries in parallel (each of 100Ah, 12V)

i.e. 2 12V, 100Ah batteries will be connected in Parallel

= 12V, 100Ah 100Ah = 12V, 200 Ah (Parallel)

Good to Know: Power in watts is additive in any configuration of resistive circuit: P Total= P1 P2 P3. Pn (Neglecting the 40% installation loss)

Charging Current for Batteries

Now the Required Charging Current for these two batteries.

(Charging current should be 1/10 of batteries Ah)

200Ah x (1/10) = 20A

Charging Time required for Battery

Here is the formula of Charging Time of a Lead acid battery. Charging Time of battery = Battery Ah / Charging Current T = Ah / A

For example, for a single 12V, 100Ah battery, The charging time would be:

T = Ah / A = 100Ah / 10A = 10 Hrs (Ideal Case)

due to some losses, (it has been noted that 40% of losses occurred during the battery charging), this way, we take 10-12 A charging current instead of 10 A, this way, the charging time required for a 12V, 100Ah battery would be:

100Ah x ( 40/100 ) = 40 (100Ah x 40% of losses)

the battery rating would be 100Ah 40 Ah = 140 Ah (100Ah losses)

Now the required charging current for the battery would be:

140Ah / 12A = 11.6 Hours.

Required No of Solar Panels (Series or Parallel) ?

Now the required No of Solar Panels we need for the above system as below.

Scenario 1: DC Load is Not Connected = Only Battery Charging

We know the famous power formula (DC)

P = VI ………… (Power = Voltage x Current)

Putting the values of batteries and charging current.

P = 240 Watts

these are the required wattage of solar panel (only for battery charging, and then battery will supply power to the load i.e. direct load is not connected to the solar panels)

240W/60W = 4 Nos of Solar panels

Therefore, we will connect 4 Solar Panels (each of 60W,12V,5A) in parallel.

The above calculations and system was only for battery charging (and then battery will supply power to the desired Load) to AC electrical appliances, which will get power through inverter and DC loads via Charge controller (via charged batteries)

Scenario 2: DC Load is Connected as well as Battery Charging

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Now suppose there is a 10A directly connected load to the panels through inverter (or may be DC load via Charge Controller). During the sunshine, the solar panel provide 10A to the directly connected load 20A to the battery charging i.e. solar panels charge the battery as well as provide 10A to the the load as well.

In this case, the total required current (20 A for Batteries Charging and 10 A for directly connected load)

In this case above, total required current in Amperes,

20A 10 A = 30A

Now, I = 30 A, then required Power

P = V x I = 12V x 30A = 360 Watts

I.e. we need 360 W system for the above explained system (This is for both Direct Load and Batteries Charging)

Now, the number of solar panels we need

360/60W = 6 Nos of Solar Panels

Therefore, we will Connect 6 Nos of Solar panels in parallel (each of 60W, 12V,5A)

Rating of Charge Controller

As we have calculated above that the charging current for 200Ah battery is 20-22 Amperes (22A For Battery Charging10A for direct DC Load), therefore we can use a charge controller about 30-32 Amp.

Note: The above calculation is based on ideal case, so it is recommended to always choose a solar panel some bigger then we need, because, there are some losses occurs during battery charging via solar panel as well as the sunshine is not always in ideal mood.

How Much Watts Solar Panel We need ?

We have shown a very simple method in the previous post to find that How much Watts Solar Panel We need for our Home Electrical appliances? depends on the sunshine time and the load in watts we need to power up an electrical appliance.

Which One Solar Panel we Select ?

Among lots of brands and material of solar panels like c-Si, String Ribon, Thin Film Solar Cells (TFSC) or (TFPV), Amorphous silicon (a-Si or a-Si:H),Cadmium Telluride (CdTe) Solar Cells, Copper Indium Gallium Selenide (CIGS/ CIS) Solar Cells, BIPV: Building Integrated Photovoltaic Panels, Hybrid Solar Cells and PV Panels, We have discussed in a very details post “different types of solar panels with advantages/advantages, cost, and applications” This way, you will be able to find which is the best type of Solar Panel for Home Use?

Aquarium Battery Backup – This Guide Could Save You !

If you want more information about my backup power system, I have set up a two-part system:

This way the Battery takes over for the periods when I’m not home, then the generator is easily set up for longer periods of no power. It works awesome!

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Read on to find out what may be the best Battery Backup system for you and why…

What Happens In Aquariums When The Power Fails?

When aquariums lose electrical power the water will begin to lose oxygen, its temperature will change based on its surrounding climate and ammonia will begin to rise. Left without attention livestock can begin to die within 1-2 hours in small aquariums and several hours on large aquariums.

Lets look at each of these problems abit more closely:

Oxygen Consumption

This has to be your first concern because it is usually the one that will cause the first deaths in an aquarium, especially if you are heavily stocked (High Bio-Load).

As all living cells need oxygen to live, the cells in your aquarium’s inhabitants will continue to require oxygen even when the power goes out. The water in the aquarium can only hold so much dissolved oxygen and if it is not resupplied the animals within it can rapidly consume all the oxygen from the water.

Another problem you may have is a current algae bloom. Algae is a plant that when it dies it can decay rapidly. This decay will cause the bacteria in your aquarium to multiply because there is an abundance of food. bacteria = more oxygen being consumed. Yep, even bacteria need oxygen to survive.

Oxygen replenishment should be your Number One concern when the power goes out as it will kill your fish way before the temperature drops, Unless its.40°C outside!

Ammonia Rise

The next task you need to sort out will be the rise of ammonia. As your fish are still living, so is their metabolism, which means they still go to the bathroom.

Under normal circumstances, the Nitrosomonas Bacteria living in your sand, rocks etc will be responsible for consuming this ammonia and converting it into the less toxic Nitrite. As these bacteria begin to die because of the lack of oxygen, the ability of your aquarium to manage ammonia decreases. This then causes the ammonia to rise.

Saltwater fish and coral are very sensitive creatures and once the ammonia level begins to reach 0.2 ppm (Parts Per Million) it becomes toxic. At 0.5ppm it is fatal. How fast it gets there is predicated on your bioload and how rapidly your Nitrifying Bacteria begin to die.

At this point, you are on your way to a tank crash.

Ways to prevent Ammonia Rise:

  • Use an ammonia test kit to monitor your ammonia level
  • Have an Ammonia Alert Badge (Amazon.com Link) on stand-by to put in your tank during power outages.
  • Small water changes every 6 hours. Be sure to match the temperature to the aquarium’s current temp! Use the water change to slightly bring the temperature closer back to normal! Small Steps!!

Temperature Drop Or Rise

For most aquarium owners the water temperature is likely to drop due to the ambient air in your part of the world being cooler than 78-80°F. For those of you that live in the hotter climates and are relying on home air conditioning /or aquarium chillers, you face a slightly different challenge of keeping your water cool.

Unfortunately, heaters and chiller are serious power hogs and running them on most battery backup systems will run them flat very quickly. Other methods must be used.

Once you have some way of keeping the water oxygenated the next part to survival is keeping the temperature stable.

Aquarium Is Beginning To Cool – There are several ways you can help to keep the temperature warm in your aquarium:

  • Small Aquariums will lose heat faster than large aquariums
  • Wrap warm blankets around and over the aquarium – Just leave a gap in the top for gas exchange
  • Keep the canopy closed as much as you can
  • Keep the door to the room with the aquarium closed
  • Prevent any draughts around the aquarium
  • Warm water on a propane stove or BBQ and place into clean pop bottles to float in the aquarium
  • Run an Inverter off your car battery (Car Running) to power a pump and a heater
  • Remove aquarium water and gently warm it on a propane stove – This is a very last resort. Be careful to check your salinity for evaporation and rapidly adding warm water to an aquarium can kill coral instantly!

Aquarium Is Beginning To Warm – There are several ways you can help to keep the temperature cool in your aquarium:

  • Open the aquarium canopy if installed
  • Open Windows to try and create a breeze – Be aware of outdoor dust
  • Evaporation is a great way to cool water. Fanning the water my work
  • Float double-bagged ziplock bags of ice in the water – do not add cold water! You will drop your salinity!

Based on the information above you can see that oxygen depletion is the first killer in your aquarium. To help minimize this we need to get oxygen back into the water and there are two ways to do this:

  • An Air Pump creating bubbles to help saturate the water with oxygen.
  • With wavemakers and powerheads to agitate the water surface to enable oxygen to be absorbed and nitrogen and carbon dioxide to be expelled.

Now we just need to find ways to get these devices to work…

What Types of Aquarium Battery Backup Are Available?

To supply battery power to an aquarium there are systems made by aquarium equipment manufacturers to run their brand of pump or filter. You can run off a UPS, an inverter plugged into a car battery or create a DIY battery powered-system tailored to your aquarium setup.

Below are the main types of battery backup systems that are available and popular among the aquarium community, but there are a few things you need to be aware of before deciding on the type of backup system you wish to implement:

  • DC (Direct Current) that is converted to AC (Alternating Current) is terribly inefficient. The units that convert this are called Inverters.Your pumps, lights and all equipment that plugs into the wall are AC.A battery of any kind only supplies DC so when the system converts DC to AC, a lot of the stored power is lost to the conversion process. This is electrical fundamentals and nothing we can do about it so you have to be aware.
  • Anytime DC is converted to AC the unit doing the conversion (UPS, Inverter) has to manually create the ‘Sine Wave’. This is the way the electrical current flows from the unit.

The Black Line is how a true AC sine wave looks when it comes into your home. Nice and smooth and uniform. This allows motors especially to run properly.

The Blue Line is very square. Almost like an On Off waveform. this is how the most basic power inverters work and it is very hard on motors and sensitive electronics. You may find your pumps squeal and your equipment does not work correctly when plugged into a cheaper inverter.

The Red Line is called a Pure Sinewave and this is created by using multiple steps to form the waveform. The more steps, the closer the waveform is to being smooth. You will see inverters now called ‘Pure SineWave Inverters’ as these units are designed to run motors and electronics, but they cost more!

Many of the pump manufacturers are becoming aware of this and you can now see DC powerheads, wavemakers and return pumps available from most of the top aquarium brands. This helps running them in power outages far more efficiently and easy!

Here are the main types of backup system being implemented within our hobby:

UPS – Uninterruptable Power Supplies

A UPS is a battery system that is mainly used in the world of computers and IT. The unit plugs into the wall and you then plug in the equipment you want it to run when the power is out.

The UPS will trickle charge while power is available and once the power goes out, the onboard batteries will run for a set period of time to allow you to safely shut down your computer. Having a computer suddenly shut off can create really annoying problems when you go to turn it back on!

Many people may have a UPS sitting around which they wish to use to run their aquarium pumps and that is fine, just be sure to test its ‘Run-Time’ every year. UPS systems are notorious for the batteries suddenly losing their capacity over the years and if you are not careful it could only run for 10 minutes when you next need it!

Some of the reputable UPS manufacturers you may want to look at are:

Here is a great calculator from APC, one of the world’s most recognized UPS manufacturers to help you decide on what size UPS to buy.Just add in the total watts of the equipment you wish to run and for how long.

If you can afford it you want to select only the ‘Smart-UPS’ models as these are the ones creating the smoothest Pure SineWave that will be the most efficient for your equipment.

2x TunzeTurbelle Stream 1700GPH powerheads – (Amazon.com Link)Input Voltage of each Pump = 120VEach powerhead draws 12 Watts = 22 wattsI want to run for 8 hours

Just enter these values into the calculator below to get the recommended sized UPC:

For this example, APC suggest a UPS of around 1500VA

Many UPS systems are being used successfully by a lot of aquarium owners and you can instantly see why. You can find some of the most popular UPS systems used by fellow aquarists HERE at Amazon.com

Aquarium Specific Battery Backup Systems

A few of the most well-known brands in the aquarium industry have designed and manufactured their own battery backup systems to either be used solely with their own products or as a generic backup system to be used with other manufacturers’ equipment.

The two main players in the game are EcoTech and Icecap.

EcoTech Marine Battery Backup System

This system was the battery backup that started off the trend of other manufacturers following suit. The EcoTech Battery is designed for use exclusively with EcoTech’s range of Vortech Wavemakers and Vectra Return Pumps.

This unit plugs into the wall and your Pump Controller then plugs into the battery pack. It is a self-monitoring, self-charging system that is totally automated, allowing you to SetForget! Great for when you are away from your home or sleeping!

With up to a possible 72 hour run time for a single Vortech Wavemaker or 30 hours for running two, this system is an absolute must for anyone running or looking to purchase an Ecotech Pump.

Additional batteries can also be added to create even longer run times, simply by plugging in another battery.Many people are now buying these to run one for the wavemakers and one for the return pump.

You can find the EcoTech Battery Backup System Here at Amazon.com

IceCap Battery Backup System

The IceCap Battery Backup system is the most versatile system on the market. Pretty much every 12-24VDC controlled pump on the market can be plugged into this system to allow your aquarium water to stay in motion during a power outage.

The kit comes with all the cables and electrical connectors you will need to ensure that your pump/s will be able to connect to the battery system.

The IceCap Battery system is rated to run for 35 hours based on a 50 Watt pump running at 30% power. If you are only running 2x 12 Watt Tunze pumps like in the example above, your battery will last much, much longer!

Just like the EcoTech battery, this can also have additional batteries connected to dramatically increase the run time. It will automatically charge and switch on when the power goes out.These features make this a great system no matter what pumps you have.

This battery system will only work with pumps that have a controller that they plug into. Any pump that plugs directly into the wall is an AC powered pump and will not work with this system.

So long as your pump is a 12-24VDC pump then you will be able to use it with this, but remember: The Bigger The Pump, The Lower The Run Time.

Having spare batteries ready to go soon cures that problem. Multiple air pumps can be run on the same aquarium if the tank is large.

These pumps are super cheap, but the batteries will cost you a bit more. The major downside to them is that if you are not home when the power goes out these air pumps are useless sitting in the aquarium stand! You have to manually turn them on, even if you have the airstones permanently sat at the back of the aquarium ready to go.

These are some great pumps for a great price to help get you out of a sudden power loss.

Requires 2x D size batteries.

Automatically Activated Air Pump

This pump takes the Standard D-Cell air pump you see above and gives it automation! The Automatic pump plugs into the wall to monitor the power. Once it senses the loss of power it automatically turns on and starts creating bubbles.

Powered by 2 D-Cell batteries this unit can be permanently plumbed into the back/corners of your aquarium, sitting waiting to run.

Having only one outlet, just like the Marina model you will have to add a Tee or Splitter to run multiple air stones.

You have to make sure that the red switch is in the ON position for it to automatically startup.

With a claim from the manufacturer to run for 48 hours on one set of batteries, most aquarists have never had to run it last that long to substantiate the claim!

This is my preferred choice for a battery-powered air pump as it does not need you to be there to activate it!


  • If you have an automatic battery-powered air pump/s permanently installed on your aquarium be sure to test it/them every week by disconnecting the plug from the wall. This ensures the unit will work when required. It only needs to run for seconds to test it.
  • Ensure your air pump is placed higher than the aquarium to prevent back siphoning of the water when it is off.
  • Install a drip loop in the electrical cord to prevent electrocution and fire hazards.
  • If the pump has not been used after 6 months, I recommend you pull the plug and run it fully until the batteries go flat to test its run time and ensure no parts are sticking.
  • When doing your test run, pull your airstones out of the water. Bubbles being pushed around by the wavemakers are not good for fish or coral.
  • Keep multiple spare sets of batteries close-by for easy change out.
  • If your pump has run during a power outage ALWAYS replace the batteries with fresh. Next time you could be away for the weekend and need the full capacity of new batteries to keep your fish alive!
  • Change your airstones every 6 months when testing your pump. They can break down over time and disintegrate.

The Limewood Air Diffusers tend to last longer and resist disintegration a lot better than the ceramic air stones.

You can find the Limewood Air Diffusers HERE at Amazon.com

Are There Any DIY Aquarium Battery Backup Systems?

Tunze Safety Connector

The Tunze Safety Connector allows anyone to build their own DIY aquarium battery backup system for for 12VDC-24VDC Tunze pumps and powerheads. The connector installs between the pump controller and the pump heads and allows the user to connect to 12vdc batteries like those used in cars and boats.

This is an odd name for what it does. The Safety Connector from Tunze is an adapter that allows you to connect a 12-24VDC battery to it and power any Tunze Turbelle Stream Controllable Powerhead or Tunze Wavebox during a power outage.

Most aquarists who set this up use 12VDC AGM Deep Cycle batteries with a battery maintainer to keep the battery/s in peak condition. Many double up the batteries to give even longer run times. Here is the typical wiring diagram:

The more AH the battery, the longer the run time for your pumps. You can easily add in a second battery in parallel to do this as shown in the diagram.

This system is a simple PlugPlay for Controllable Tunze Turbelle Stream and Wavebox pumps, but the Safety Connector can also be used to run other manufacturers’ pumps and controllers, You just have to hack the wiring to suit your controller/pump.

For a great backup system for under 200 here are the main parts you will need:

To work out what size AH (Amp Hour) battery you will need you can use this super helpful calculator HERE from Batterystuff.com, but first, you will need the details below:

The calculator needs the pumps Amperage, but most pumps are given in Watts:-

eg. Tunze Turbelle NanoStream 6055 Controllable PumpWattage = 4 to 18W depending on speed ran (I used 18W for worst-case scenario)

Divide Watts by Volts to gets Amps:18Watts ÷ 12Volts = 1.5Amps

  • 1.5Amps – This goes into the calculator
  • Next Select Hours to Run – eg 24 hours
  • Next Select AGM Battery
  • Hit Calculate

For this pump to run for 24 hours I need at least a 72AH 12V AGM Battery like This One Here at Amazon.com

Inverter Backup Systems

The above system works great if you have any 12VDC to 24VDC controllable pumps, but what do you do if all your pumps plug straight into the wall? The answer is very similar to the above system, except you swap out the Tunze Safety Connector for an Inverter.

An Inverter is a device that converts 12VDC from batteries into 110VAC for your pumps to be able to run. For this type of system to work properly you need to pick an inverter with the following characteristics:

  • Pure SineWave to ensure motors run safely smoothly
  • Automatic switching when it senses a power loss
  • Sufficient wattage to run all your pumps

For a great backup system for around 350 here are the main parts you will need:

Here is a typical Inverter Connection Diagram:

Here is a great little calculator for calculating Run Time of a Battery Inverter system CLICK HERE

WARNINGThis type of installation requires you to have some electrical wiring knowledge. Always seek professional advice or installation when attempting to install a system like this.TheBeginnersReef.com accepts no liability for your actions!This stuff hurts if you get it wrong!

What Can You Run Off An Aquarium Battery Backup System?

Aquarium battery backup systems typically run one or two powerheads. Systems with larger capacity can run DC-powered return pumps, or heaters and lights if designed large enough. The main benefit to battery systems is to automatically keep a pump or two running during outages of a few hours.

When you lose power you may feel like you need to run everything to maintain the health of your aquarium, and while in a perfect world this would be very helpful, but most of us can’t afford the 20K investment in an automatic whole house generator!

Most of the power outages we face are usually in the region of a few hours to half a day. Any longer than that and you are going to need at generator of some form to keep your tank alive.

If you would like more detailed information about providing emergency power to your aquarium during long power outages please have a read of this article:

We now know that air pumps and water movement give us the best opportunity for survival but what about plugging in other equipment.

Return Pumps

Easy if they are DC-powered and are not large 100W pumps. The more wattage a device pulls, the sooner your battery power will run out. The Controllable DC pumps from Ecotech and Reef Octopus are your best option if you wish to easily add them to your battery backup system.


These are not required to be ran unless you start getting into days without power. By the time you need to run lights for your corals, you will probably have been on a generator-powered system for a while!

Another way you could get light to your aquarium is by reflecting light from a window with a large mirror towards your tank. Even this small amount will help your coral. Fish do not require light to survive.

Protein Skimmer

Running a protein skimmer is only useful if you have your return pump circulating water to your skimmer. Again, if you have a DC-powered skimmer you could hook up both your return pump and your protein skimmer to one backup system so they work together.


Heaters and Chillers are the biggest power-hungry items on your aquarium! Running at several hundred watts they can really drain a battery quick. Most of the time they click on and off and only run for a set amount of time per hour, but if your home is cold for example, because the furnace has stopped, then your heater will be constantly on.

Aquarium Controller

Having an aquarium controller like the Neptune Apex hooked up to a battery backup system can be really handy to automatically drop the flow rate and thus the power consumption of the pumps it controls when it senses a power outage.

The controllers themselves use only a few watts of power so are no major drain on a backup system, in fact many aquarists will put their aquarium controller, internet router and Wi-Fi modem on their own UPS or battery backup system so the controller can send you a text or an email to let you know the power is out!

This is super helpful if you want to then get home and fire up the generator so your whole tank (and Furnace will run.

If you want more information on what Aquarium controllers can do to make your life easier please check out my article about them:

How Long Do Aquarium Battery Backup Systems Last?

Aquarium battery backup systems on average will run between 8-48 hours depending on the system installed and the equipment it powers. Powering just a single pump will run twice as long as running two pumps. Run Time = Battery Capacity/Amps drawn by the equipment.

Running pumps/wavemakers off a battery backup can easily give you hours if not days of use looking at the options available. But if you wanted to run more items of your aquairum system? How long would they last?

Its pretty simple math to work it out:

Example #1:DC Return Pump DC Protein Skimmer

Ecotech Vectra S1 Return Pump – 55W AquaMaxx ConeS DCQ-2 Controllable In-Sump Protein Skimmer – 25WEcotech Marine Battery = 18Ah

Running off 1 Ecotech Marine Backup Battery with wiring rigged to connect the Aquamaxx ConeS Skimmer:

80W Total Load ÷ 12Volts = 6.66Amps

18Ah (Amps Per Hour) Battery ÷ 6.66Amps = 2.70Hours

Running the Vectra Return Pump the Aquamaxx Skimmer together will flatten the Ecotech Battery in just under 3 hours!

Run the same pump and skimmer off a Tunze Safety Connector and a 100Ah battery:

100Ah Battery ÷ 6.66Amps = 15 Hours

Add another 100Ah Battery (200AhTotal) = 30 Hours

If you want to run anything but powerheads, you need to have a dedicated Battery Backup system with very large AH Batteries!

Example #2:AC Return Pump AC Protein Skimmer

Ehiem 1250 Return Pump – 28W @ 110V ACBubble Magnus Curve 7 In-Sump Protein Skimmer – 16W @ 110V AC Pure Sine Wave Inverter with Battery = 18Ah

Using the calculation from the Inverter Run Time Calculator:

Backup Time = Battery AH x 12V x N x Efficiency of Battery / Load in Watts

Where,Battery AH = Ampere Hour Capacity of BatteryN = Number of 12 V Batteries neededEfficiency of Battery = Generally it is 0.8, which is the max. power factor of home standard

18Ah x 12V x 1 x 0.8 = 172/(2816) = 3.9 Hours Run Time

This is a very similar run time to the DC Ecotech powered system.If you change out the battery to 100Ah:

100Ah x 12V x 1 x 0.8 = 960/(2816) = 21.8 Hours Run Time!

Example #3:AC Return Pump AC Protein Skimmer 250W Heater

Ehiem 1250 Return Pump – 28W @ 110V ACBubble Magnus Curve 7 In-Sump Protein Skimmer – 16W @ 110V AC Ehiem Jager Heater – 250W Pure Sine Wave Inverter with Battery = 100Ah

Using the calculation from the Inverter Run Time Calculator:

Backup Time = Battery AH x 12V x N x Efficiency of Battery / Load in Watts

Where,Battery AH = Ampere Hour Capacity of BatteryN = Number of 12 V Batteries neededEfficiency of Battery = Generally it is 0.8, which is the max. power factor of home standard

100Ah x 12V x 1 x 0.8 = 172/(2816250) = 3.2 Hours Run Time!

To run your Return Pump, Protein Skimmer and the Heater (Will say the heater is on 24/7 because the house is cold – worst-case scenario) for 24 hours you will need a Battery Bank of at least 800Ah!

This will cost you 1000 for just the batteries and inverter!

Are There Any Aquarium Power Alternatives To Batteries?

You are better off just installing a battery backup system to run a couple of powerheads for a few hundred dollars and then invest in a good gasoline or propane generator you can hook up and then run EVERYTHING off.

Be sure to buy one that is large enough to also run your furnace to help keep the house warm in the winter! Happy Wife, Happy Life remember! If your partner is cold but your fish are alive then I can see some arguments starting

To size one correctly add up all the wattage of the devices you plan to run using the calculations above and ensure the ‘Continuous Use Wattage’ on the generator is higher than your number.

For even more ideas on preparing for a power outage and what to do during and after, I have a great article dedicated to it:

Further Reading

If you are into the techie side of this hobby you might find the following articles interesting:

Hi, I’m Richard and I have been an avid aquarist for over 30 years with a passion for Saltwater Aquariums. I love to pass on my knowledge to help others get the same amount a pleasure out of this hobby as I do. View my About Me page to find out more about me my mixed reef aquarium.

Recent Posts

Having to move an aquarium over a long distance is bar far one of the most labor-intensive moves you can do with an aquarium. Not only do you have the task of moving the house but you also have to.

Moving house is said to be one of the ‘Top 5 Most Stressful Times’ in our life! Now if you have an aquarium, especially an established saltwater aquarium this now sends that stress toward the very.

About Me

My name is Richard and I have been an avid aquarist for over 30 years. My journey began, like many others, with the introduction of two goldfish and a small aquarium. I was hooked! It took me years of searching to help find all the best information to help me become successful with a Saltwater Aquarium. This site is designed to put all that helpful information in one easy-to-find place.

How To Calculate Battery Backup Power

Deciding on which battery to use means knowing how much power it can supply. There is a way to calculate battery backup power and this post should give you an idea on how to do it.

How Do You Calculate Battery Amp Hours (Ah) for a UPS?

You will need to know the battery voltage, device load in watts, how long the UPS needs power the device in hours, the inverter efficiency, and discharge coefficient. With this information, you can determine the Amp Hours (Ah) of your UPS.

  • W: Device Load = 100W
  • T: Time on backup power = 8 hours
  • V: Battery Voltage = 120V
  • E: Inverter Efficiency = 90%
  • C: Discharge Coefficient or Power Factor = 0.8
  • Ah: Amp Hours = ?

Amp hours of the UPS = (W × T) ÷ (V × E × C)

What Is the Backup Time of a 100 Ah Battery?

Battery backup time (T) = Ah x V/W

Using the same variables above, then if we have:

The battery backup time calculation formula

The “battery backup time calculation formula” is a way to calculate battery backup power. The formula for the calculation can be found in this video:

Here are some good universal power supplies with extended backup battery capability:

As an Amazon Associate, SelectSafety earns commissions from qualifying purchases made through links in this post.

How Do I Calculate Battery Needs?

Battery need = daily load in kWh x days of electricity needed / kWh of usable capacity per battery

Here’s an illustration assuming one and a half days’ worth of electricity needed:

You expect an average daily load of 10 kWh. For 1.5 days of electricity backuip you will need 15 kWh of storage (10 kWh x 1.5 days).

The batteries you’re using each have 2.8 kWh of usable capacity available.

15-kilowatt hours divided by the battery capacity of 2.8 kWh equals 5.3 batteries.

How Do You Calculate the Power Output of a Charger?

Power output of a battery charger (in watts) = current in Amps x Volts x Efficiency

When power loss is ignored, the input and output power is the same. However, you must factor in the real-world output by multiplying it by an efficiency factor.

Here is an example for a typical laptop charger, assuming these values:

typically have output specifications of 19.5 VDC and 2.31 A.P (in watts) = 19.5 2.31 = 45 watts, which is the standard (approx.)

Here are some highly rated battery chargers to check out:

How Much Power Does a UPS Battery Backup Use?

Most home-use UPS units consume very little power (3-10 watts per hour) to keep their batteries fully charged. They are normally rated between 92 and 95 percent in terms of energy efficiency.

Related Questions and Answers

How long will a 150 Ah battery last?

To calculate how long a backup battery with a specific amp-hours (Ah) will last, use this formula to convert its capacity to kilowatt-hours (kWh) then divide by the kW of load to ge the number of hours it will last.

Battery kWh = battery Ah × battery Volts/1000

Let’s assume we have these values:

Next we want to determine how many hours this battery will last with our anticipated load (in kW).

How long battery will last in hours (H) = battery kWh / 0.4 kW load from a lightbulb

This assumes the battery is completely charged at the beginning. The battery will last longer if the load is lowered, and shorter if the load is increased.

How many watts is a 150 Ah battery?

To get the watts (W) from the amp-hours (Ah) of a battery, simply multiply the amp-hours of the battery times the battery’s voltage.

Battery W = battery Ah x battery Volts

150 amp-hour 12 volt batteries are popular for solar and backup installations. The watts available from this battery are as follows:

How many amps is a 150 Ah battery?

The term “150 Ah” refers to a battery’s ability to provide a continuous current of 15 amperes over a 10-hour discharge period (that is, 15A x 10h = 150Ah).

How do you calculate battery watt-hours (Wh)?

Watt-hours is another unit of measurement for battery capacity (Wh). Amps and battery voltage are multiplied to arrive at Wh. In other words, the total energy stored in a 12V 100Ah (12-volt, 100-amp-hour battery) is 12 x 100, or 1200 watt-hours. 1200Wh is the maximum power that may be derived from either a 12V 100Ah or 24V 50Ah battery.

How long will a 100Ah battery run a 1000w inverter?

A fully loaded 1000-watt inverter could be operated for 34 minutes on a 12 volt 100 Ah deep-cycle battery with a consistent depth of drain of 50%. This estimate considers the 95 percent average efficiency of pure sine wave inverters.

How do you calculate how long a battery will power a device?

A battery’s lifespan may be determined by its capacity. Calculate the battery’s entire capacity and divide it by your circuit’s power to estimate how long your battery will survive.

How Many Watts Is 600VA?

To get the watts simply multiply the volt-amperes (VA) value by the power factor of your load.

If your 600VA load has a 100 percent power factor, you’ll need 600 watts to power it. In other words 600VA x 1 power factor = 600W.

If your 600VA load has a power factor of 0.8, you will need 480 watts to power that load. 600VA x 0.8 power factor = 480W.

Is VA equal to Watts?

An electrical circuit’s perceived power may be expressed in terms of volt-amperes (VA). DC circuits can’t make use of volt-ampere measurements; only AC systems can. Volt-ampere to watt (VA to w) conversion is easy. Watts are equal to VA times the power factor of the system.

What does 600VA or 1500VA mean?

VA means “volt-amperes” and is a UPS’s estimated maximum “instantaneous” output power. VA is a simple power rating that doesn’t include any reference to time or load. It does not inform you how long it will be able to provide a particular load (in watts) with power. It is just a quick indication of the maximum short-term load the UPS backup power system can handle.

VA allows different power supplies to be compared at a high level. A UPS rated at 600VA will output less than one rated at 1500VA.

The VA rating does not imply that it can output that amount of watts. A 1000VA power supply cannot output 1000 watts. Real-world wattage ratings for a power supply range from 50% to 75% of the VA rating in real-world use. This power factor (PF) of the unit must be taken into account to estimate the actual output of any UPS.

How long will a 1500VA UPS run?

A 1500VA UPS will generally provide backup power for between 10 and 60 minutes, depending on how many machines it must power and their wattage draw. You can generally operate a PC, networking equipment, and a monitor for about 10 minutes on a 1500VA UPS.

How many watts does a 40 amp battery charger use?

A battery charger that consumes 40 amps can charge 480 watts at 12 volts (actually a bit more but this is good for comparison sake).

How is LED power calculated?

If you want to know how much electricity an LED is using, multiply its voltage by its current in amps. Your LEDs’ power consumption is calculated as a wattage.


There is a way to calculate the amount of energy in a battery backup unit that is available to power your home. However, it may be better to rely on the data provided by the battery manufacturer and any information in the guidebook to help make this decision.

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