12V vs 24V: What’s The Difference In Battery Systems. 24v power bank

V vs 24V: What’s The Difference In Battery Systems?

We all use batteries in typical day-to-day life. Whether it be in our remote control, watch, car, or RV, batteries are a part of our lives. Most of the time, we don’t need to think about the voltage of a battery. However, when working with DC power systems for RV’s boats or off-grid applications, a serious decision needs to be made between 12V vs 24V.

This article will discuss 12V and 24V systems and the differences in 12V vs 24V batteries. Let’s get into it!

What is the Voltage of a Car, RV, or Boat Electrical System?

Most cars, RVs, and boats utilize a 12-volt electrical system, although there are some exceptions. So, when are 12V vs 24V batteries used?

To understand more about batteries, we must first understand what volts or voltage is. Voltage is the amount of electrical pressure it takes to push an electrical current. Take a look at what volts are to get a better understanding of this concept.

What Does “12V” Mean?

12V tells us that the battery supplies 12 volts under a nominal load. The same principle holds for a 24V battery bank in that it provides 24 volts.

As we discussed before, most car and RV batteries are 12V.

12V batteries are used in most vehicles because the electrical components such as the starter, lighting, and ignition systems are designed to operate on 12 volts.

We sometimes use 24V battery systems in larger trucks and busses due to the vehicle’s higher power needs and long cable runs. You can also see 24V used in larger boats and some RVs with elaborate solar systems.

Another typical application for a 24V system is on trolling motors for fishing boats.

How is a 24V System Made?

A 24V system is where you produce 24V under nominal load. There are a couple of ways to create a 24V power system. One way is to purchase a 24V battery. The other is to use two 12V batteries in series to create a 24V system. Let’s take a look at these options in a little more detail.

What is a 24V Battery?

One way to create a 24V system is to use a 24V battery. 24V batteries are less common than their 12V counterpart and are harder to come by. 24V batteries are also relatively expensive.

However, they do take up less space than running other batteries in series. So, if space is a concern, a single 24V battery may be a better choice for you.

↳ Click here to check out our 12V and 24V Battle Born Batteries product specs.

How Do You Connect 12V Batteries In Series?

The most common method for building a 24V system is to run batteries in series.

Running batteries in series means they have a single electrical path equal to the sum of the system’s volts. So, if you have two 12V batteries wired in series, then 2x12V=24V.

To create a 24V system using two 12V batteries, you would wire the first battery’s “” positive terminal to the “-“negative terminal of the second battery. The remaining negative and positive connections get wired to the component you want to power just as you would if you were using a single battery. You can accomplish the same thing using four 6 volt batteries.

To make this easier to digest, let’s look at something we are all familiar with, a flashlight. Many flashlights use batteries that are running in series. Suppose you have a large flashlight that uses four “C” size batteries.

When you install the batteries, they are in a single row with negative touching positive. This is a series circuit. Each of the “C” batteries is 1.5V. We learned earlier that when batteries run in series, then the output voltage is the sum. In this case, the flashlight runs off 6 volts.

Comparing 12V vs 24V – Benefits of Each

When looking at 12V vs. 24V systems, there are some pros and cons to each system type. Let’s take a look at some of the pros of each.

12V System Benefits

As we talked about earlier in the article, 12V systems are relatively common. Most vehicles use 12V systems as components used in vehicles are designed to operate on 12V. The alternators generate 12V to charge the battery.

When it comes to RVs, most appliances such as RV refrigerators and all the lighting work on 12V as well. 12V systems only require one battery and work well for low-power applications and short wire runs.

24V System Benefits

24V systems are beneficial because you can use smaller diameter wire and reduce amperage by two times. Using smaller diameter wire can reduce wiring costs and decrease the space needed to run wiring. This is especially important where long wire runs are required.

But wait, how can you run a smaller wire with more voltage?

You can actually run a wire 2x smaller than an equivalent 12V circuit. This is because the higher voltage requires less current to produce the same power. Since we are running less current or amps, we can use a smaller wire. This is the same reason power is transmitted on power lines at very high voltages. The wires can be much, much smaller and carry lots more power!

In addition to smaller wires, 24 volt systems operate more efficiently in motors and inverters. Often, the same solar charge controller operating on 24V vs 12V will handle twice the solar input.

Comparing 12V Vs 24V Cons of Each

As there are pros of 12V vs 24V systems, there are also cons to each type of system. Some of the pros of one system can become a con of the other.

Downsides of 12V

12V systems require massive wires when pulling large loads because the current (amps) are higher. As we have already learned, 24V systems reduce the current or amps two times, then a downside of a 12V system is the amperage is double that of a 24V system at the same power.

Because 12V batteries use two times the amperage at a given power draw, they are less efficient than a 24V battery due to resistive losses.

Downsides of 24V

If you are using a 24V system in an application with 12V appliances, you will need a converter to reduce the voltage to 12V. The variety of components and devices that run on 24V are not as plentiful as what is available in 12V.

Although you can charge a 12V battery with the alternator of a vehicle, you won’t be able to do that with a 24V system if the chassis is a 12V system. Additional DC-DC converters are needed to accomplish this task.

When To Use A 12V vs 24V System

Now that we have learned a little about 12V vs. 24V systems, we need to understand when we should use one over the other.

When building a DC (direct current) battery system, it’s crucial to understand your power requirements to run the appliances you need. The energy that is consumed by a device is measured in watts. Once you know your wattage requirement, you can determine what system is required.

If your requirements are below 3000W, you can generally get by with a 12V system.

Many recommend 24V systems when your power needs are above 3000W or generating 3000W of solar or more. When you get to this point, the benefits of a 24V system outweigh the cons because you can run smaller and increase the system’s efficiency.

If your power consumption is even higher, above 6000W, you can benefit from an even larger DC system and consider stepping up to 48V.

24V DC Benefits For Solar

Many DC MPPT solar charge controllers have higher voltage capabilities to handle higher panel voltages. They, however, have a hard current limit.

When using a 50 amp rated charge controller on a 12V battery bank, you can use the controller with 700 watts of solar. If you use that same charge controller on a 24V battery system, it can connect to 1400 watts of solar panels. This means that half the number of solar charge controllers is needed. They will also operate more efficiently at 24 volts.

V vs 24V, Which Is Right For Me?

It isn’t always a clear-cut decision. There are many variables to consider when determining which one is the best choice.

Now that we understand these systems better, they are not as intimidating as we originally thought them to be. Whether you end up with a 12V or 24V system, you now understand the differences. You can assess your needs and make an educated decision.

Things You Should Look for When Buying a Portable Power Station

Are you shopping for a portable power station? Here are five things you should look for when buying one.

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With the advancement of battery technology, portable power stations have the capacity and raw power to reliably power electronics that require much greater power than your regular power bank can provide. Although not as powerful as gas-powered generators, they are quieter, lighter, and don’t require fuel to start delivering power.

So, getting a portable power station is likely the better solution if you’re looking for a quiet and mobile device to power your smartphone, laptop, computer, or TV. To help you find a quality one, here are five things you should look for when buying a new power station.

Battery Capacity

When looking for a portable power station, battery capacity is the most important specification you should be looking for. The bigger the battery capacity, the longer you can run your devices per charge. So, in general, buy the highest capacity battery you can.

However, considering size, weight, and cost, you might want to go for a more calculated approach when considering the battery capacity of your portable power station.

Since different manufacturers use different metrics to measure the battery capacity of their portable power stations, knowing battery capacity can be confusing. The most popular metrics used in measuring battery capacity would include mAh (milliamp hour), Ah (Amp hour), Wh (Watt hour), and kWh (kilowatt-hour).

Electronic devices usually indicate their maximum power consumption in Watt-hours, which you can find marked on various types of power supplies. If the power supply indicates its power rating in Watts, remember that one watt is equal to one Watt-hour.

To better understand how long a portable power station can power your device, you first need to know its battery capacity in Watt-hours. To do that, you can check its Watt-hour rating. But if it only indicates battery capacity in mAh (milliamp-hours) or Ah (Amp-hours), you can take those numbers plus its rated system voltage (12v or 24v) and look up its Watt-hour rating using this graph below:

Battery Amp/milliamp Hours

So let’s say your laptop is rated to operate at a maximum of 90W or 90Wh, and the portable power station has a battery of capacity of 40,000 mAh on a 12-volt system. Using the table above, you’ll see that the power station has a battery capacity of 480Wh. If you divide that by the 90Wh that the laptop uses, you can expect around 5 hours of runtime without accounting for power loss and other variables.

Battery Technology

Another important thing you should be looking for in a portable power station is battery technology or the type of battery it utilizes. The type of battery used in a portable power station heavily determines the size, weight, cost, charging speed, and how long your power station can keep producing AC power before cutting off.

Lithium-ion (Li-Ion), lithium-polymer (Li-Po), and lead-acid batteries are the most common batteries used in portable power stations.

Lithium-ion batteries charge three times faster than lead-acid batteries and are the most energy dense out of the three. On the other hand, lithium-polymer batteries are less energy dense than Li-Ion batteries but have fast charging capabilities and are generally safer to use than Li-Ion and lead acid batteries. While lead-acid batteries are the most affordable of the three, but are also bulky, slow-charging, and have the least energy density.

If you’re looking for something packable, lighter, and can be used frequently, then a Li-Ion battery is usually worth the investment. But if you want something safer, fast charging, and have the lowest passive discharge rate, then a Li-Po battery power station might be the better option.

Lead-acid batteries aren’t usually recommended, but if you really need a cheap set-and-forget backup power station to use during emergencies, then a lead-acid power station should suffice.

Inverter Technology

Depending on the device you’re trying to power, having the right inverter in your portable power station can save your delicate devices from damage and make them work as efficiently as possible, saving battery charge.

Power inverters are electrical components that convert your battery’s direct current (DC) to alternating current (AC). DC is used to charge your battery-powered handheld devices, such as your phone, tablet, and Bluetooth earbuds, while AC is used to power more power-hungry devices, such as your laptop, computer, TV, and gaming consoles.

In general, there are two types of power inverters; they are pure sine wave inverters and modified sine wave inverters. Pure sine wave inverters provide clean sine waves that produce AC, while modified sine wave inverters use pulse width modulation (PWM), which makes an electronic signal that tries to mimic a pure sine wave signal.

If you will power precision, delicate, and highly sensitive equipment, having a pure sine wave inverter should be your only option. But if you’re only going to use the power station to power your computer, monitors, console, and TV, then a power station with a modified sine wave inverter should work fine while saving you quite a bit of money.

Peak and Continuous Wattage

Peak and continuous wattage are also important specifications you should be looking for when buying a portable power station. Although portable power stations are usually used to power computers, TVs, and other electronic gadgets, they can also power things like refrigerators, corded power tools, electric fans, and kitchen appliances such as blenders and food processors. However, these devices can only be powered by a portable power station if they have enough peak and continuous wattage.

Most power-hungry devices and equipment need certain peak or surge watts just to jump-start and turn them on. Once turned on, they will need a lower but continuous supply of power known as continuous watts or rated watts.

To know how much peak and continuous wattage you need out of your portable power station, here is a list of typical appliances and their watt ratings:

Giant Power 26.4kWh 24V 1100AH AGM Battery Bank (6V cells)

Buy now and pay later, with 6 months interest free. You pay over time weekly, fortnightly or monthly, whichever suits you best. Applications are quick, and get a decision in real-time.

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Overview

Deep cycle AGM Batteries are perfect for applications that require either frequent cycling or renewable power storage. Common uses include running appliances when camping away from power, using with a solar panel for charging, running in a dual battery system in a vehicle, or providing safe power on a boat.

Features

  • Sealed construction (VRLA)
  • Maintenance free operation
  • Non-Spillable, Non-Gassing
  • Designed Service Life 12 years
  • Ideal for frequent cyclic discharge
  • Exceptional deep discharge recovery performance
  • Low self-discharge characteristic

Bank Inclusions

  • 8x 550AH 6V AGM Deep Cycle Battery
  • 6x 2 BS Series Cable 250mm length
  • 2x 2 BS Parallel Cable 600mm length

Please note: Wiring supplied with this bank is designed for a standard battery bank configuration. Other wiring configurations available upon request.

Reviews

Giant Power 26.4kWh 24V 1100AH AGM Battery Bank (6V cells) has a rating of 5.00 /5 based on 3 reviews.

I really like these batteries, performance far better than old AGM set.

Shane T on 28 November 2020

Totally confident with purchase, staff are very friendly and knowledgeable, happy to answer questions and give advice when required. You will be hard pressed to find a better bunch of people to deal with if you’re living off grid or wish to power up your mobile home

MIKE B on 19 October 2020

So far very happy with the product ( 8 X Giant 550A/H 6volt cells). Holding over 24v during the night draw. Unfortunately they took over 5 weeks to land in Perth from Brisbane mainly due to the transport companies computer system being hacked and the lock down caused by the Covid 19.

DAVID C on 8 July 2020

Specifications

Giant Power 6V 550AH AGM Deep Cycle Battery
Cells Per Unit 3
Voltage Per Unit 6
Nominal Capacity 550Ah@C100 to 1.75V per cell @25ºC
Dimension Length: 295 ±2mm Width: 178 ±2mm Total Height (with Terminal): 425 ±2mm
Approx Weight Approx 57.5 Kg (Tolerance ± 1.5%)
Max Discharge Current 4000A (5 Sec)
Internal Resistance Approx 1.1mΩ
Operating Temp.Range Discharge :.20 ~ 60 o C Charge : 0 ~ 50 o C Storage :.20 ~ 60 o C
Nominal Operating Temp. Range 25°C ± 5°C
Float Charging Voltage 6.8 VDC/unit Average at 25oC
Max Charging Current Limit 60 A
Equalization and Cycle Service 7.3 (7.4 for equalization) VDC/unit Average at 25oC
Self Discharge Giant Power batteries can be stored for more than 6 months at 25ºC. Self-discharge ratio less than 3% per month at 25ºC. Please charge batteries before using.
Terminal Terminal F14/F22
Container Material A.B.S UL94-HB, UL94-V0 Optional

Warranty

For more information, please read our full warranty policy

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LiFePO4 Battery Voltage Charts (12V, 24V 48V)

Just so you know, this page contains affiliate links. If you make a purchase after clicking on one, at no extra cost to you I may earn a small commission.

Here are lithium iron phosphate (LiFePO4) battery voltage charts showing state of charge based on voltage for 12V, 24V and 48V LiFePO4 batteries — as well as 3.2V LiFePO4 cells.

Note: The numbers in these charts are all based on the open circuit voltage (Voc) of a single battery at rest. If your LFP battery manual has its own discharge curve and charging parameters, they should take precedence over the ones below.

V LiFePO4 Battery Voltage Chart

VoltageCapacity
14.6V 100% (charging)
13.6V 100% (resting)
13.4V 99%
13.3V 90%
13.2V 70%
13.1V 40%
13.0V 30%
12.9V 20%
12.8V 17%
12.5V 14%
12.0V 9%
10.0V 0%

Here’s a printable version of the above chart:

And here it is graphed out:

12V 100Ah LiFePO4 batteries are currently some of the most popular for off-grid solar power systems. They’re a drop-in replacement for 12V lead acid batteries, and a great upgrade.

They are fully charged at 14.6 volts and fully discharged at 10 volts. They are made by wiring four 3.2V LiFePO4 cells in series.

12V LiFePO4 Battery Charging Parameters

  • Charging voltage: 14.2-14.6V
  • Float voltage: 13.6V (or disabled)
  • Maximum voltage: 14.6V
  • Minimum voltage: 10V
  • Nominal voltage: 12V or 12.8V

V LiFePO4 Battery Voltage Chart

VoltageCapacity
29.2V 100% (charging)
27.2V 100% (resting)
26.8V 99%
26.6V 90%
26.4V 70%
26.2V 40%
26.0V 30%
25.8V 20%
25.6V 17%
25.0V 14%
24.0V 9%
20.0V 0%

Here’s a printable version of the above chart:

And here it is graphed out:

24V lithium iron phosphate batteries are another popular option for DIY solar power projects. You can either buy a 24V LiFePO4 battery off the shelf, or get two identical 12V LiFePO4 batteries and connect them in series to make a 24V battery bank.

They are fully charged at 29.2 volts and fully discharged at 20 volts. They are made by connecting eight 3.2V LiFePO4 cells in series.

24V LiFePO4 Battery Charging Parameters

  • Charging voltage: 28.4-29.2V
  • Float voltage: 27.2V (or disabled)
  • Maximum voltage: 29.2V
  • Minimum voltage: 20V
  • Nominal voltage: 24V or 25.6V

V LiFePO4 Battery Voltage Chart

VoltageCapacity
58.4V 100% (charging)
54.4V 100% (resting)
53.6V 99%
53.2V 90%
52.8V 70%
52.4V 40%
52.0V 30%
51.6V 20%
51.2V 17%
50.0V 14%
48.0V 9%
40.0V 0%

Here’s a printable version of the above chart:

And here it is graphed out:

48V batteries are more popular for larger solar systems. They rarely make sense for small-scale projects. Designing a higher voltage solar system allows you to keep amperage low, thereby saving you money on wiring and equipment costs.

48V LiFePO4 batteries are fully charged at 58.4 volts and fully discharged at 40 volts. They are made by connecting 16 3.2V LiFePO4 cells in series.

48V LiFePO4 Battery Charging Parameters

  • Charging voltage: 56.8-58.4V
  • Float voltage: 54.4V (or disabled)
  • Maximum voltage: 58.4V
  • Minimum voltage: 40V
  • Nominal voltage: 48V or 51.2V

.2V LiFePO4 Cell Voltage Chart

Here’s a printable version of the above chart:

And here it is graphed out:

Individual LiFePO4 cells have a nominal voltage of 3.2 volts. They are fully charged at 3.65 volts and fully discharged at 2.5 volts.

You can buy individual LiFePO4 battery cells online. They’re best used for making your own lithium batteries. You can wire cells in series and parallel to make LFP batteries with your desired voltage and capacity combinations.

3.2V LiFePO4 Cell Charging Parameters

  • Charging voltage: 3.55-3.65V
  • Float voltage: 3.4V (or disabled)
  • Maximum voltage: 3.65V
  • Minimum voltage: 2.5V
  • Nominal voltage: 3.2V

Ways to Check LiFePO4 Battery Capacity

Measure Battery Open Circuit Voltage with a Multimeter

Pros: Moderately accurate

Cons: Must disconnect all loads and chargers and let battery rest

A battery’s voltage changes depending on its charge and discharge rate. Plus, LiFePO4 batteries have a relatively flat discharge curve from around 99% to 20% capacity. Because of these factors, it can be hard to estimate their state of charge from voltage alone.

To get an even somewhat accurate estimate of LiFePO4 battery capacity based on voltage, you first need to disconnect any loads and chargers from the battery. (Don’t forget to disconnect your solar panels from your charge controller first!)

Let the battery rest for a little while — I usually wait 15-30 minutes — and then measure its open circuit voltage with a multimeter.

Compare your measurement to the right voltage curve above, or the state of charge chart in your battery manual. Use it to get a rough estimate of your battery’s remaining capacity.

For example, I own the Ampere Time 12V 100Ah LiFePO4 Deep Cycle Battery (Ampere Time has since rebranded to “LiTime”). I wanted to check its capacity after having stored it for a few weeks. I brought it out of storage and measured its voltage with a multimeter. I got 13.23 volts.

I then compared this number to the 12V LiFePO4 state of charge chart above, as well as the one in the battery manual.

Based on the charts, I’d estimate my battery’s state of charge was somewhere around 80%.

I like this method best for estimating the state of charge of an LFP battery I’ve just received or just pulled out of storage. The battery is already at rest and not connected to anything. I find it too inconvenient to disconnect everything once the battery is in use.

DIY lithium battery builders will also measure the voltage of used (and new) battery cells — such as LFP cells and 18650 lithium batteries — to see which are good and which are duds.

Use a Battery Monitor

Pros: Most accurate, convenient

Cons: Good battery monitors are expensive

The best way to track battery capacity is to connect a good battery monitor — such as the Victron SmartShunt or Victron BMV-712.

Battery monitors track the amount of amp hours consumed to accurately estimate the state of charge. They also display useful system specs such as battery voltage and current. Some connect via Bluetooth to your phone so you can check your LiFePO4 battery’s capacity in a mobile app.

Use a Solar Charge Controller

Pros: Convenient

Cons: Inaccurate

“My solar charge controller already measures battery voltage. I can just use it to check battery capacity.”

This voltage reading is largely inaccurate. It suffers from all of the problems mentioned above, plus it’s done while the battery is connected to loads and chargers.

(Not to mention that some charge controllers have incorrect voltage readings.)

For example, recall that when I checked my battery’s voltage with a multimeter at the battery terminals, I got a voltage reading of 13.23 volts. That correlates to a roughly 80% state of charge.

But when I connected my battery to an MPPT charge controller, the controller measured 13.0 volts. That correlates to a roughly 30% state of charge — a difference of 50%! Granted, some charge controllers have much more accurate battery voltage readings than others.

After all, voltage drops under load. And a charge controller is a load. If I were to connect a solar panel and start solar charging the battery, its voltage would quickly jump.

Checking battery capacity this way is convenient. But beware that it can be quite inaccurate. I generally use this voltage reading just to make sure my battery isn’t close to being fully discharged.

If you use this method and want to make sure it’s as accurate as possible, you can buy a battery voltage sensor, such as the Renogy Battery Voltage Sensor or Victron Smart Battery Sense. A voltage sensor gives the controller a more accurate voltage reading, especially in solar power systems with long wire runs.

LiFePO4 Voltage FAQ

What is the voltage of a fully charged 12V LiFePO4 battery?

A fully charged 12V LiFePO4 battery will have a charging voltage of around 14.6 volts and a resting voltage of around 13.6 volts.

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What is the charging voltage of a 12V LiFePO4 battery?

The charging voltage for 12V LiFePO4 batteries is 14.2 to 14.6 volts. This works out to a charging voltage of 3.55 to 3.65 volts per cell.

Most often, you’ll see LiFePO4 battery chargers and solar charge controllers use a charging voltage of 14.4 volts for 12V lithium batteries.

What is the minimum voltage of a 12V LiFePO4 battery?

The minimum voltage of many 12V LiFePO4 batteries is around 10 volts. The battery’s BMS should detect when the battery voltage falls to around 10 volts and trigger low-voltage cutoff. (Low-voltage cutoff is also called low-voltage disconnect, which you’ll sometimes see abbreviated LVD.)

Note: Some batteries have higher cutoff voltages, such as 10.6V. So the limit in your battery manual may not be exactly 10V.

LiFePO4 batteries in low-voltage cutoff enter a sleep mode to protect the battery cells from over discharge. LFP batteries in sleep mode can have very low voltage readings, usually less than 5 volts. You may think that the battery is dead, but really it’s just sleeping.

Once a battery enters sleep mode, it needs to be woken up. Refer to your battery manual for instructions on how to do this. If your manual doesn’t have instructions, check out our tutorial on how to wake up a sleeping LiFePO4 battery.

What is the float voltage of a 12V LiFePO4 battery?

LiFePO4 batteries don’t need to be float charged because they don’t leak charge the way lead acid batteries do.

If you can, disable float charging on your charge controller or battery charger. If you can’t, prevent the battery from entering float charge by setting the float voltage to that recommended in the battery manual — usually 13.6 volts ± 0.2 volts.

How much can you discharge a LiFePO4 battery?

Many LiFePO4 batteries can discharge 100% of their rated capacity every time with no ill effects.

However, many manufacturers recommend discharging only 80% to maximize battery life. In fact, some brands state the cycle life of their batteries based on 80% depth of discharge (DoD).

For comparison, lead acid batteries can only discharge 50% of their rated capacity. So a 12V 100Ah LFP battery has as much usable capacity as a 12V 200Ah lead acid battery.

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