12V Battery Types: Which One Is For You. 12v battery low

V Battery Types: Which One Is For You?

When it comes to 12-volt battery types, the choice can seem a little daunting to those unfamiliar with battery technology. All 12-volt battery types are similar in that they provide power for your 12V electrical system. However, there are significant differences in how they’re designed, their capacity, the amount of maintenance required, and the cost to buy and install.

Join us as we take a closer look and find the right battery type for you!

What is a 12V Battery?

Twelve-volt batteries are commonly used in RV, boat, and other automobile systems. From a technical perspective, a battery uses one or more cells to allow a chemical reaction creating the flow of electrons in a circuit. Batteries do not create energy or power on their own. Batteries simply store energy for you to use when you need it.

The power you get from a battery is direct current (DC) power and is different than the alternating current (AC) power you get from the wall outlets in your home. If needed, DC power can be converted to AC power using an inverter.

You can connect multiple 12-volt batteries in series or in parallel to get either a higher voltage or more storage capacity. For example, if you connect two 12 volt batteries in series, you will have a 24-volt system. If you connect these same 12-volt batteries in parallel, you will still have a 12-volt system, but it will be able to power the same device for twice as long as a single 12-volt battery.

Your 12V battery system will power most of your basic systems like your lights and some appliances in your RV. You’ll charge this battery system while plugged into shore power and draw from it while traveling or boondocking.

V Battery Types

When it comes to 12-volt rechargeable storage batteries, two primary types are currently used, Lead-Acid and Lithium-ion.

Lead-acid batteries have been around for a long time, while Lithium-ion is the newer technology. There are many types of Lead-acid batteries, so let’s start by taking a look at them first.

Flooded Lead-Acid Batteries

Lead-acid batteries are the most basic 12V battery type. They’re made of lead plates suspended in a sulfuric acid solution. This creates a chemical reaction that allows for energy to be stored.

Flooded Lead-Acid batteries are the most common variety of lead-acid batteries. You’ll need to have the right amount of water in these batteries to keep them functioning correctly. This means periodic maintenance is required to monitor this battery. Flooded lead-acid batteries generally last 2 to 5 years, depending on use and maintenance. The cost can vary widely, starting at around 100.


Since these are the most common kind of batteries, they’re also the most readily available and cheapest upfront to replace when the time comes. This type of battery also does not have any electronics in it and can produce a large current for a short period. This makes them ideal for starting batteries in vehicle engines.


Because these batteries need a specific amount of fluid in them to operate properly, you’ll need to be comfortable maintaining your battery system every 3-6 months. This can be difficult, depending on where your batteries are located in your RV.

Flooded lead-acid batteries also have the shortest overall lifespan of the main battery types and can be negatively affected by extremely hot or cold temperatures. You must also install them in an upright position or they will leak water and acid and fail.

Sealed Valve-Regulated Lead-Acid Batteries (VRLA)

Sealed valve-regulated lead-acid (VRLA) batteries eliminate most of the maintenance needs of their flooded counterparts. As their name implies, they’re sealed shut with the necessary ingredients to run correctly for the life of your battery.

Since they are sealed, as they discharge the chemical reaction starts to build up the pressure of hydrogen gas. Most of this gas gets recombined back to water in the battery, but during Rapid charge or discharges, the gas pressure may exceed the battery’s safety specs. The regulator valve is used to relieve this excessive pressure but, unfortunately, at the same time, slowly decreases the capacity of the battery.

These are also reasonably easy to find come replacement time. Sealed lead-acid batteries last about the same length as flooded ones (2-8 years) and tend to cost a few hundred dollars.


No maintenance means a more hassle-free life for you. While they’re more expensive than flooded batteries, they’re still among the most budget-friendly battery options. Per energy delivered however, these batteries will cost more than flooded batteries.


As mentioned, the price increase may be important to cost-conscious buyers. The inability to maintain the battery, as well, may result in less than optimal performance over their life as some gas is lost. A properly maintained flooded lead-acid battery will outlast a sealed battery, but a poorly maintained flooded battery will have a shorter lifespan than a sealed battery.

Gel 12 Volt Batteries

The next step up in lead-acid 12V battery types is the gel battery. Gel batteries suspend their lead plates inside a thicker gel instead of a liquid and are considered a type of VRLA battery. Gel 12V batteries generally last 2-5 years and cost anywhere from 100 up to 800-900. The cost typically goes up as the capacity of the battery increases.


Gel batteries don’t require any regular maintenance, and you don’t have to worry about fluid leaking out as with flooded batteries. Because of this, they do not need to be installed upright. They also work well in high temperatures, unlike other types of lead-acid batteries. This makes them commonly used in special use cases or as high-temperature starting batteries for engines.


Gel batteries need more care when charging to make sure they’re not damaged. They require a particular type of charge controller and need slower charging cycles at lower voltages. All of this means an increased cost to the overall system beyond just the price of your batteries. Like other lead-acid types, deep discharges and fast recharge are not great for these batteries.

AGM 12 Volt Batteries

What is an AGM Battery? It is an Absorbent Glass Mat (AGM) technology that is a sealed lead-acid battery type.

In AGM 12V battery types, the lead plates sit between fiberglass saturated electrolyte mats. This allows increased efficiency in discharging and recharging. AGM batteries usually last 4-7 years and start in the 200 range.


AGM batteries don’t require any regular maintenance, are leak-free, and work well in most temperatures. They also don’t require the special charging equipment and care needed with Gel batteries and tend to have a longer lifespan.


These additional benefits come at a cost. AGM batteries can be significantly more expensive than lead-acid or gel batteries with similar capacities.

Challenges For All Lead-Acid Battery Types

All of the batteries we have discussed so far are variations of lead-acid battery technology and utilize the same internal chemical reaction. Because of this, they all suffer similar drawbacks in operational performance.

All lead-acid battery types require strict usage and charging requirements to get their full lifespan. Monitoring discharge and charge levels is required to get the full lifespan from these batteries as deep discharges and partial charges will damage the battery. These batteries also have long recharge times and need a special absorption charge cycle to get fully charged. This makes lead-acid batteries a poor choice for applications that involve lots of charges and discharge cycles, like renewable energy power applications.


Lithium-ion batteries have the highest storage capacity of all RV 12V battery types and have the fastest and most efficient charging. They also last the longest before needing to be replaced, sometimes 3-5 times longer than traditional batteries. Lithium-ion batteries are lighter and don’t require the regular maintenance that other types of batteries do.

Finally, lithium-ion batteries can discharge more of their stored energy without damaging the battery or reducing your power, unlike lead-acid batteries. Because of all these charging benefits, this type of battery performs very well in repetitive and partial charging tasks like solar power systems.


Lithium-ion batteries are by far the most expensive up-front of the 12-volt battery types available. Additionally, since lithium-ion technology is newer, you will need to upgrade more than just your batteries if you want to convert to a lithium-ion battery system.

However, lithium-ion batteries last much longer and also employ electronics inside them that both protect the battery and you. These overall make the battery much safer than a lead-acid alternative.

Lastly, they will limit current to the nameplate label. This means most Lithium-ion 12 volt batteries will not work as an engine starting battery.

How to Choose the Best 12 Volt Battery Type For You

Picking the best 12-volt battery type for you is about trade-offs. Each battery type has advantages and disadvantages, and these can vary depending on your style of RV or travel.

The RVer on a tight budget may go for cheaper flooded lead-acid batteries, even if the long-term cost is more. Those who often operate in very hot or cold temperatures may want to avoid lead-acid batteries, however, in favor of a lithium-ion battery that will protect itself and perform better.

Gel batteries eliminate some of these issues, but the owner needs to be really comfortable with additional charging requirements.

RVers looking for low maintenance batteries should FOCUS on sealed lead acid, gel, AGM, or lithium batteries and ignore flooded lead-acid batteries altogether.

Lithium-ion batteries are the obvious top choice, as they include an optimal mix of safety, low maintenance, efficiency, long lifespan, and power.

Choose the Best 12V Battery Type for Your Adventure

All of the different 12-volt battery types may seem complicated, but in the end, the results are the same. Once you understand your needs and budget, you should be able to use the pros and cons we discussed to make the best choice for you and your RV to keep yourself powered on the road for years to come.

We encourage you to check out our line of lithium-ion batteries assembled right here in the USA for your next RV, marine, or off-grid power need!

Battery’s Good, But the Car Won’t Start. Now What?

When your car won’t start, the first thing to do is check the battery. The vast majority of the time when a vehicle refuses to start up, the cause is a battery with little or no juice. However, sometimes it isn’t that easy. If the battery terminals are clean and properly connected, and a battery tester shows that it’s in good shape, you’ll need to keep troubleshooting to find the problem.

This diagram is a little basic and out of date, but it roughly explains the components of a typical 12-volt charging system:

The battery is a vulnerable component because it can be weakened by age, temperature, and even vibration. But it’s not the only component that needs to be inspected and replaced, and as the years have gone by, it’s become one of the more expensive components in the charging system. There was a time when 75 would buy the best battery on the shelf. These days, you’re looking at 140 to 200.

You don’t want to spend that money unless the battery truly is the problem. We’re not only going to describe how to test these components but the order in which you should be testing, which will uncover typical problem areas and save you from spending more than you have to.


You’re going to need a few diagnostic tools, but we’ll keep it to the absolute minimum.

The first thing to consider purchasing is a battery tester with a load tester. This kind of tester not only tests the state of charge at rest but also the health of the battery while it’s subjected to the load of a start cycle.

There are fancier electronic testers, but this old-school analog tester has a couple of advantages:

  • You can usually buy one for less than 40.
  • It doesn’t require batteries to operate. This thing is going to be hanging in your garage — unused — for years. (Something that requires a fresh set of AAs is going to fail when you need it to work most.)

If you don’t want to invest in a battery tester like this, you can always bring the car — or just the battery — to a good auto parts store. Most have a battery tester that can immediately tell you whether or not your battery is the problem.

The other thing to consider is a decent multimeter. You can spend a ton of money on one with features you’ll never use. Find one in the 29 to 45 range with a large digital readout and you should be fine.

This Klein Tools auto-ranging multimeter is about 50 and has all the features you’ll need. It’s available at big box home centers, so you won’t have to find one at a specialty electronics warehouse.

One note: a multimeter can test the voltage of a battery, but it won’t run a one-person start cycle on it the way a battery tester will, so we’d recommend getting both. You can have a second person start the car while you hold a multimeter’s probes against the battery posts, but it’s not as convenient.

The other thing every garage needs is a battery charger. Trickle chargers have gotten smaller, cheaper, and more sophisticated over the years. You can pick up a BlackDecker charger that you simply plug in and not think about for around 30.

Testing in Order

If you want to make this as expensive as possible, just start replacing parts without knowing if they’re the problem.

If you want to get out of this as inexpensively as you can, you need to test a few components to find the root of the problem. We’ve laid these tests out in order of (a) ease, (b) expense, and (c) likelihood of failure.

Test the Battery

Even if it’s new, you need to understand what’s going on with the battery. Attach the tester to the battery. If the needle’s not moving at all, then you’ve got a dead battery. What’s more important is its condition under load.

By pressing the “Load Test” button, you’re simulating a start cycle. The battery should be able to hold 8.5 volts for 15 seconds at 0 degrees Fahrenheit. If it doesn’t, then you know the battery is at least part of the problem.

If it does, then you need to start investigating elsewhere.

Test the Cables

Battery cables go bad all the time. Not only do the connections get crusted up with corrosion, but that corrosion can creep down inside the cables, rendering them all but useless.

A voltage drop test can tell you if your battery cable is the problem. Using the Voltage setting on the multimeter, first, touch the probes to the battery terminals to determine the voltage of the battery. A fully charged battery should have about 12 volts ready to go.

To perform a voltage drop test of the cables and terminals, touch one probe to the battery post, and then the other to the terminal. It should read at or near zero. If it’s reading any lower (the numbers will be represented as negative decimals:.0.07, for example), then you’re losing voltage in your cables.

Watch this video for a more detailed explanation:

Check the Belt

If the battery is discharged and the cable connections are good, you’ll want to fully charge the battery and start looking at the condition of the charging system.

The second cheapest component in the entire charging system next to the cables is the belt, so let’s look at that next. For decades now, cars have used serpentine belts with idler pulleys that maintain tension. If the belt is squeaking or showing signs of slippage, it might not be allowing the alternator to work the way it should. If the belt hasn’t been changed and it looks cracked, it’s time to replace it anyway.

It’s typically a less than 50 replacement, but you also want to replace the idler pulley at the same time. There’s a bearing in it that will go bad at the least convenient moment. At best, this will lead to a dead car. At worst, it could blow your head gasket. This is because this same belt not only spins the alternator, but also the water pump. They’re easy to replace and don’t cost much more than the belt.

Test the Alternator

Typically, if your alternator is no good, it’s going to throw a “CHARGE” light on the dash or show you that you’re not running at 14.3 volts. But, you can’t always count on your dashboard to tell you exactly what’s wrong.

Using your trusty multimeter, you can test exactly how much voltage the alternator is putting out. Simply attach the two probes to the positive and negative terminals of the battery, make sure the probe leads are out of the way of any moving parts in the engine bay, and fire the engine up.

The multimeter should show somewhere between 14.2 and 14.7 volts. If it’s showing less, the battery isn’t being charged as well as it should. This will be especially apparent when you’re running accessories like lights, wipers, rear defroster, and the radio. If it shows MORE than 14.7 volts, the alternator is overcharging the battery and will eventually cook the life out of it.

Test for Parasitic Drain

It’s hard to place this test using our hierarchy of ease, expense, and the likelihood of a problem. If you’ve left a light on, that should be easy and free to fix. If you’ve got a short in a hidden wire because a mouse chewed through it, that could be difficult and expensive to diagnose and fix.

In general, though, less-than-obvious parasitic drains aren’t as common as some of the other issues on our list. However, if your battery is discharging overnight — which you’re determining because you’ve charged the battery, then tested the voltage the next morning as described in step 1 — then you might actually have some kind of a constant drain happening.

To perform this test, remove the negative battery cable from the battery. With the multimeter set to the highest amp scale (read your multimeter’s instructions), touch one of your multimeter’s probes to the cable terminal, and one to the battery post.

The readout on your multimeter shouldn’t be higher than 50ma (milliamps). If it’s more than 50ma, you’ve got something that’s drawing power from the battery.

To determine what’s causing that draw, you’ll need to follow the instructions in the video below. The process involves removing and replacing every single fuse in the car one by one until that voltage draw goes to fewer than 50ma.

Check the Starter

If the cables, belt, battery, and alternator are okay, then (and only then) start looking at the starter. Testing it requires taking it out, meaning that you’re probably going to end up replacing it anyway. So unless you’re pretty ambitious, you’ll probably end up at a mechanic shop. But by this point, you’ll be able to provide your technician with a lot of information about the condition of your charging system. That means you save the mechanic time which he’d otherwise be charging you for. That’s a small win in our book.

We hope this information helps get you back on the road with as much money left in your as possible. And hey, if you decide your current vehicle is more than it’s worth, we know where you can find a new one.

Lead Acid Battery Voltage Charts (6V, 12V 24V)

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 lead acid battery voltage charts showing state of charge based on voltage for 6V, 12V and 24V batteries — as well as 2V lead acid cells.

Lead acid battery voltage curves vary greatly based on variables like temperature, discharge rate and battery type (e.g. sealed, flooded). The voltage to battery capacity chart in your battery manual should always take precedence over the generic, averaged ones listed below.

Note: Estimating state of charge based on open circuit voltage is only accurate when batteries are at room temperature and have been resting — i.e. disconnected from all loads and chargers — for several hours.

V Lead Acid Battery Voltage Charts

Printable Chart


6V lead acid batteries are used in some DC devices like lights, pumps and electric bikes. You can also wire two in series to create a 12V battery bank. They are made by connecting three 2V lead acid cells in series.

6V sealed lead acid batteries are fully charged at around 6.44 volts and fully discharged at around 6.11 volts (assuming 50% max depth of discharge).

6V flooded lead acid batteries are fully charged at around 6.32 volts and fully discharged at around 6.03 volts (assuming 50% max depth of discharge).

V Lead Acid Battery Voltage Charts

Printable Chart


12V lead acid batteries are popular in solar power systems and other 12V electrical systems. They’re widely available and have a low upfront cost. Many car and marine batteries are 12V lead acid batteries. They are made by connecting six 2V lead acid cells in series.

As far as I can tell, lead acid is still the most popular rechargeable battery type for DIY solar power systems. Lithium iron phosphate (LiFePO4) batteries have become a lot more popular in recent years, though, in large part thanks to their dramatic price drops we’ve seen over the last decade.

12V sealed lead acid batteries are fully charged at around 12.89 volts and fully discharged at around 12.23 volts (assuming 50% max depth of discharge).

12V flooded lead acid batteries are fully charged at around 12.64 volts and fully discharged at around 12.07 volts (assuming 50% max depth of discharge).

V Lead Acid Battery Voltage Charts

Printable Chart


24V lead acid batteries are another common option for solar power systems. Working with higher voltages helps keep amperage low, saving you money on wiring and equipment. They are made by wiring in series twelve 2V lead acid cells or two 12V lead acid batteries.

24V sealed lead acid batteries are fully charged at around 25.77 volts and fully discharged at around 24.45 volts (assuming 50% max depth of discharge).

24V flooded lead acid batteries are fully charged at around 25.29 volts and fully discharged at around 24.14 volts (assuming 50% max depth of discharge).

V Lead Acid Cell Voltage Charts

Printable Chart


Individual lead acid cells have a nominal voltage of 2 volts (sometimes listed as 2.1 volts). You can buy 2V lead acid cells and connect them in series-parallel configurations to build a battery bank with your desired voltage and capacity.

2V sealed lead acid cells are fully charged at around 2.15 volts and fully discharged at around 2.04 volts (assuming 50% max depth of discharge).

2V flooded lead acid cells are fully charged at around 2.11 volts and fully discharged at around 2.01 volts (assuming 50% max depth of discharge).

Ways to Check Lead Acid Battery Capacity

Measure Open Circuit Voltage with a Multimeter

Pros: Accurate

Cons: Must disconnect all loads and chargers and let battery rest for several hours

To properly estimate battery capacity based on open circuit voltage, first disconnect everything from your battery and let it rest at room temperature for several hours. (Battery University recommends at least 4 hours.)

Then, simply use a multimeter to measure the voltage at the battery terminals and compare the number you get to the state of charge chart in your battery manual. If your battery manual doesn’t have a chart, use the relevant one listed above.

For example, I recently wanted to test the remaining capacity of a 12V 33Ah sealed lead acid battery I own. The battery was already at rest and at room temperature — it had been sitting disconnected in my basement for the past couple weeks.

So I grabbed my multimeter, prepped it to measure DC voltage, and touched the probes to the battery terminals. I got an open circuit voltage of 12.63 volts.

I couldn’t find my battery’s manual, so I referred to the 12V sealed lead acid voltage chart above to estimate its capacity. Based on that chart, I’d estimate it had about 80% capacity left.

Check Specific Gravity with a Hydrometer or Refractometer

Pros: Accurate

Cons: Only works for flooded lead acid batteries

You can use a hydrometer or refractometer to measure what’s called the specific gravity of your lead acid battery. Measuring the specific gravity is another way to estimate state of charge.

Because this method requires you to open the battery to access the electrolyte solution inside, it only works with flooded batteries.

I’ve only ever used sealed lead acid batteries, so I unfortunately can’t run you through the steps on how to do this. Refer to the steps listed in your battery manual, or the product manual for your hydrometer or refractometer.

Use a Solar Charge Controller

Pros: Convenient

Cons: Inaccurate

If you’re using your lead acid battery in a solar power system, your charge controller probably measures battery voltage for you.

You may be thinking you can just use this reading to get an accurate estimate of your battery capacity. Unfortunately, using battery voltage to estimate capacity while the battery is connected to chargers and loads is very inaccurate.

Battery voltage varies greatly depending on factors like temperature and rate of discharge. Plus, the battery voltage reading given by some charge controllers can be inexact. Some charge controllers only display one decimal place, and others have wide margins of error. For example, one cheap PWM charge controller I tested claimed a battery voltage margin of error of ± 0.2 volts.

Still, I know most DIY solar enthusiasts will use this reading most often, if not exclusively. It’s a hassle to disconnect everything from your battery and let it rest just to measure its state of charge more accurately.

If that’s you, just keep in mind how inaccurate this number can be. Don’t think you can know the precise state of charge of your battery from it. Just use it to get a general idea of whether or not your battery is close to being fully charged or discharged.

Lead Acid Voltage FAQ

Note: To reiterate, the recommended voltages and state of charge chart in your battery’s manual should take precedence over the generic ones listed below.

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

A 12V sealed lead acid battery will have an open circuit voltage of around 12.9 volts when fully charged.

A 12V flooded lead acid battery will have an open circuit voltage of around 12.6 volts when fully charged.

To accurately estimate a battery’s capacity based on its voltage, you must first disconnect all loads and chargers from the battery and let it rest at room temperature for several hours.

What is the minimum voltage of a 12V lead acid battery?

The minimum open circuit voltage of a 12V sealed lead acid battery is around 12.2 volts, assuming 50% max depth of discharge.

The minimum open circuit voltage of a 12V flooded lead acid battery is around 12.1 volts, assuming 50% max depth of discharge.

How much can you discharge a lead acid battery?

Many lead acid batteries can only be discharged up to 50%. Discharging them more can cause permanent damage. You should never completely discharge a lead acid battery to 100% depth of discharge. Doing so can shorten its lifespan greatly.

Here is a graph showing the relationship between depth of discharge and life cycles for non-deep-cycle lead acid batteries:

As you can see, consistently discharging a lead acid battery to 100% can severely shorten its lifespan.

What is the float voltage of a 12V lead acid battery?

The float voltage of a sealed 12V lead acid battery is usually 13.6 volts ± 0.2 volts.

The float voltage of a flooded 12V lead acid battery is usually 13.5 volts.

As always, defer to the recommended float voltage listed in your battery’s manual. Some brands refer to float as “standby.” Sometimes, the float voltage will even be listed on your battery label.

How I Got the Numbers in These Charts

To get the numbers in the voltage tables above, I looked up the datasheets for 7 popular brands of lead acid batteries. I found the state of charge charts in each and averaged them together for the final values.

Here are the datasheets I used for the sealed lead acid values (2 AGM, 2 gel), along with the page number where I found the voltage chart:

And here are the ones I used for the flooded values:

Creating these charts was far from an exact science. Only a couple of the datasheets listed open circuit voltages by capacity in table format with exact numbers. Often, they included a graph from which I’d have to infer the numbers. What’s more, the graphs often had wide bands rather than thin lines, as if to convey a margin of error or range of possible values — what I came to see as the brands hedging against providing an exact number.

Other brands provided exact numbers, but only for 0%, 25%, 50%, 75%, and 100% capacity values. From these I had to create linear functions to estimate the values between them.

I calculated all the numbers for 2V lead acid cells first, then multiplied these values by the respective number of cells in series to get the values for 6V, 12V and 24V batteries. Finally, I rounded all the values to two decimal places.

Tesla will now send push notifications when 12V battery needs to be replaced

Tesla is seemingly now issuing push notifications when the vehicle’s 12V battery needs to be replaced.

user BLKMDL3 shared a screenshot of a notification he received from Tesla that informed him his 12V battery must be replaced soon. It also encourages him to schedule a service appointment to replace the battery.

“Really Smart, hope they add push notifications when you have low tire pressure or other important alerts,” BLKMDL3 says in the tweet.

Since Tesla has access to virtually every piece of information on the vehicle, it certainly seems like a welcomed feature to notify owners if anything needs to be repaired or replaced, like windshield wipers, wiper fluid, or a headlamp.

The 12V battery in Teslas powers smaller motors and functions around the vehicle, including lights, power window motors, wiper motors, power lift gate, washer fluid pumps, ABS electronics, the main display and more.

Last year, Tesla switched away from using a 12V lead-acid battery to a lithium-ion battery. Lead-acid batteries perform well in gasoline-powered vehicles because they produce the high output needed to start the engine. However, that high output is not needed in an electric vehicle.

Lithium-ion batteries last longer, weigh less and are much better optimized for electric vehicles, as they will last the lifetime of the vehicle and never need to be changed.

Whether you have a lead-acid or lithium-ion low-voltage battery, they’re both charged through the vehicle’s main battery pack instead of an alternator like a traditional vehicle.

With Tesla at the forefront of battery technology, specifically for vehicles, a study conducted by Dr. Jeff Dahn and his team at Dalhousie University in Halifax, Canada, says that the Austin-based automotive company may be able to produce batteries that last 100 years. Dahn and his team has been working exclusively with Tesla since 2015 to develop new Li-ion batteries.

Earlier this year, Tesla started delivering Model Ys from their Austin, Texas Gigafactory with their new 4680 battery pack. These battery packs have already seen impressive charging rates and are showing very promising potential.

Don’t miss out!

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Tesla Cybertruck Shown Off With Possible Ventilated Seats, Camera Cleaner and [Video]

The Petersen Automotive Museum’s inaugural Electrified Cars Coffee meet was memorable. Tesla’s much-anticipated Cybertruck rolled into the spotlight. The star-studded truck was helmed by none other than Tesla’s Chief Designer, Franz von Holzhausen. He drove the eye-catching electric pickup truck to the event and served as the host of Petersen’s first-ever EV-only Cruise-In.

Ventilated Seats and : Unveiling Cybertruck’s Interior Updates

As the electric vehicle community delved into the details, an intriguing feature stood out. the Cybertruck appeared to flaunt ventilated seats. Further, the vehicle’s fit and finish looked polished, suggesting that the Cybertruck seen at the event could be a near-final production model. Attendees also noticed a significant refinement in the truck’s fully constructed interior.

Redesigned ‘Vault’ and Other Noteworthy Exterior Details

The Cybertruck’s unique ‘vault’. its bed. appeared to have undergone some design tweaks. Observers noted the presence of a slot close to the tailgate, hinting at potential outlets in the truck bed. The charge port, a key element in any EV, was seen on the Cybertruck’s rear fender, departing from the original 2019 prototype design. The lighted Cybertruck logo replaces the traditional Tesla logo on the NACS port. a fun Easter egg for fans.

FOOKN CRAZYYYY! Another tonneau in action video, but also the tailgate dropping. Cybertruck is going to just be otherworldly @elonmusk @Tesla

Forward-Thinking Design for Optimum Functionality

The red-tinted cameras of the Cybertruck suggest that the vehicle will be armed with Tesla’s Hardware 4 computer and cameras, elevating its autonomous driving capabilities. Another eye-catching design detail was the front bumper camera equipped with an overhead slot, possibly designed to wash the sensor if it gets covered with dirt or mud.

As the EV community eagerly waits for the official rollout, these latest updates from the Petersen Automotive Museum event showcase the significant progress Cybertruck has made since its 2019 debut. These enhancements underline Tesla’s relentless pursuit of innovation, delivering more than expected while staying true to their unique design language.

The ventilated seats and revamped ‘vault’ are just a peek into what’s in store for future Cybertruck owners. They’re a testament to Tesla’s dedication to combining luxury, convenience, and sustainability in their vehicles. And with Franz von Holzhausen at the design helm, there’s no telling what other surprises may be in store as the Cybertruck gets closer to production.

A quick peek inside the Cybertruck as Franz drives it off piccom/Fly2XxWugP

— Ryan Zohoury (@RyanZohoury) June 25, 2023

A Close Look at Tesla’s Model Y as a Police Cruiser [Video]

When it comes to police vehicles, performance, reliability, and durability are non-negotiable. Recognizing the need for a more modern, sustainable solution, Model PD has converted Tesla’s Model Y into fully equipped, robust police cruisers.

According to Zack Wilson, a spokesperson for the company, they considered other electric vehicle manufacturers. Still, Tesla was the clear winner, stating, The reason we’re sticking with Tesla is that from what we’ve seen, Tesla is the only company that can meet the demand. Not only that. But the Model Y is the safest car on the planet.

Modifications Made

The Model Y police cruiser sees a host of changes that elevate it from a sleek consumer vehicle to a reliable law enforcement workhorse. The typical glass roof has been replaced with a carbon fiber one, providing the strength required to house police lights and dome lights. Durability is a crucial factor here, with the interior upholstery being swapped out for a more resistant material to withstand the rigors of police work, including the wear and tear from handcuffs and guns.

A keyboard has been added to the bottom of the screen, and with one press of a button, the display will switch from the Tesla screen to a Windows interface for police officers to access law enforcement information.

To ensure the safe and secure transport of suspects, the back seats have been converted to a vinyl surface, complete with a plexiglass enclosure. In an interesting shift, the standard Tesla wheels have been replaced with traditional police steel wheels, topped off with Goodyear police-rated tires.

Outperforming the Competition

Compared to a traditional police vehicle such as the Ford Police Interceptor Utility, the Model PD’s Tesla Model Y-based cruiser presents some compelling advantages. The Model PD boasts an impressive 131/117 MPG equivalent in city/highway driving, compared to Ford’s 23/24 MPG. Additionally, it delivers a powerful 384 horsepower and 375 lb-ft of torque, outshining Ford’s 285 horsepower and 322 lb-ft of torque.

The Tesla-based cruiser also offers significant savings in terms of operational costs. Based on 20,000 miles per year, the Model PD’s estimated annual electric cost is just 605, compared to a whopping 5,085 for fuel in the Ford. Furthermore, the estimated yearly maintenance cost for the Model PD is a modest 350, starkly contrasting the Ford’s 1,300.

The Future of Policing with Tesla

Model PD plans to expand its portfolio by converting Tesla Cybertruck into a police vehicle. If the Model PD’s transformation of Model Y is anything to go by, the Cybertruck could revolutionize policing in terms of resilience, functionality, and sustainability.

The Model PD’s transformation of the Tesla Model Y into a fully equipped police cruiser embodies a significant stride in the evolution of law enforcement vehicles. With its impressive performance stats, cost-efficiency, and commitment to sustainability, the Model PD shows that Tesla is not just meeting the demand. it’s shaping the future of policing.

Your gas car uses an alternator to charge its 12-volt battery. An electric car uses a device called a DC-DC Converter. Here’s how that works.

Most electric cars get around with just one big, high voltage battery pack full of rechargeable lithium cells that drive the motor. But, EVs also have a regular old 12 volt lead-acid battery, just like the one in your fossil-fueled car. This may seem odd or redundant, but the old-school battery serves multiple important purposes. One of the problems with a big, high voltage battery is that it can be quite dangerous. Isolating the battery from the rest of the car’s electronics is important. To achieve this, electric cars use a contactor.

The Contactor: It’s All About Safety

The contactor allows the main battery power to the vehicle to be shut off when the car is in an accident, being worked on, or simply not being driven. It’s an important safety measure that helps prevent electrical fires and/or electric shocks, and allows the main traction electronics to be de-energized when not in use. Contactor is a fancy word for what is essentially a big switch that controls the flow of current from the battery pack. A contactor is turned on by supplying voltage to a coil. This coil acts as an electromagnet, moving a larger set of contacts, which allows current to flow out of the high-voltage battery. Switch the coil back off, and the contacts spring apart, breaking the circuit and disconnecting the battery. It’s just like a big relay, basically.

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The need for such a device poses a problem: How do you energize this contactor in order to connect the main traction battery to the rest of the car’s electronics? An easy way to do this is to use a nice, reliable 12 volt battery. Fancier solutions would work too — such as modern Li-Ion 12V batteries — those are already shipping in some cars. But with lead-acid car batteries already proven and rated to last in an automotive environment, and available all over the world, why reinvent the wheel? Or the battery, for that matter.

The other main area where the 12-volt battery helps is in all the ancillary systems in a modern car. Things like blower fans, electric Windows, headlights, and infotainment systems have all historically run on 12 volts. They all work great as-is. Engineering an electric drivetrain is strenuous enough, so it makes sense from a cost and durability standpoint to use existing, proven designs for systems that can largely carry over.

Electric cars use huge voltages for their main traction batteries. anywhere from 300 to over 800 volts. Higher voltages allow for lower currents for a given power level, and lower currents cut down on resistive losses for the main power circuits. But high voltages are undesirable for other uses, as they require more care in terms of insulation and protecting cables from damage. These high voltages are dangerous to people and other equipment, so any such cabling must be produced to a high standard and insulated properly to avoid issues.

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It’s also difficult to switch high voltages; particularly with direct current from batteries, switches tend to arc when flipped and get damaged, and semiconductors to handle higher voltages inherently cost more. There are vague plans to switch more cars over to 24 V or 48 V systems in the future. but these voltages are still much lower and safer than modern high voltage batteries for regular use. For now, though, 12 volt accessories are the norm.

For more information on the presence of 12 volt batteries in EVs, we reached out to an engineer at a major OEM. He broke it down, saying:

If we take the EV bit out for a second 12V systems are used in vehicles to supply power to various modules and accessories we find in cars. 12V systems were not always the answer, if we look back 6V used to be the answer, many military applications use 24V and 48V is starting to creep in, but at this point 12v is most prolific. Regardless of the voltage we need some sort of power supply to run our modules, and there are A LOT of 12v parts sitting around, and the automotive industry loves to re-use parts.

Yes, you could have a radio that is supplied by 350V but that’s expensive and as I mentioned before there’s a lot of 12v designs ready to just plop in.

There’s No Alternator In Aa EV, There’s A DC-DC Converter

Thus, having source of 12 volt power for all these accessories is a must. However, as anyone who’s ever had a busted alternator knows, you won’t keep things running for long on just a regular car battery. EVs need a way to keep their 12 volt battery charged, and to help supply power to all the accessories when they’re running. EV batteries output direct current (DC), so simple AC transformers are not an option to step the voltages down from the main battery to charge the 12-volt one. Instead, the job falls to the DC/DC converter.

You might ask: Can’t we just use a DC/DC converter to run everything and forget the 12V car battery altogether? Well, no. You still need the 12V battery to turn on the contactor that connects the high-voltage traction battery to the rest of the car. On top of that, regulations get sticky, too. Our engineering contact notes:

Now you could only have a DC-DC converter that is always on to power the various modules but being always on that would mean the HV battery would be slowly discharging over time, always. This isn’t really ideal from a storage scenario and then there are some regulations (ECE-R-100 and FMVSS-305) which state in the event of a crash the HV bus must be discharged in a certain amount of time and the HV battery disconnected from the rest of the vehicle. So again we have some situations where we want systems to be powered while the vehicle is “off” and this is where that 12v battery comes in.

I’ve been an electronics fanatic since I was just a few feet high. Teaching myself to understand the basic concepts has served me well, as modern cars are as reliant on electronics as they are on mechanical principles. It’s also made me popular with anyone that needed help installing a car stereo. Let me lay down the basics of how DC-DC converters work so you might better understand what’s going on under the hood of your garden-variety EV.

How DC-DC Converters Work: It’s All About The Switching

There are a wide variety of DC/DC converter designs, some capable of turning a small voltage into a bigger one (boost converters), turning a big voltage into a smaller one (buck converters), or doing both (amazingly, called buck-boost converters). For electric vehicles, a buck converter is the part for the job, stepping hundreds of volts from the main battery back down to the nominal 12-14ish volts desired to charge the 12V battery and run accessories.

Some manufacturers do use bidirectional buck-boosts in this application for niche edge cases. However, when stepping down the high traction battery voltage to the 12 volts for the accessory subsystem, the mode of operation is by and large identical to a regular buck converter.

A buck converter takes a DC supply at the input, and puts out a lower DC voltage to the output load. In our case, the DC supply is the main battery voltage, sitting at many hundreds of volts. Our output load is our 12 volt accessory system. The buck converter steps the voltage down using a diode, an inductor, a capacitor, and a transistor that’s switched by some additional circuitry. For those unfamiliar, a transistor is a special type of electronic switch that can be turned on to allow current to pass or turned off to stop the flow. In that way, it’s similar to a contactor, but is electronic instead of electromechanical, switches much faster, and works at much lower voltages and currents.

The diode is a part that only lets electricity flow one way. The inductor and capacitor are devices that store electrical energy in magnetic fields and electric fields, respectively. For reasons that are best explained with complex physics going well beyond the scope of this article, inductors tend to oppose changes in current, while capacitors oppose changes in voltage.

So how does the buck converter operate? When the transistor is first turned on, current begins to flow from the higher voltage DC supply (in our case, the battery). The positive voltage is present at the cathode of the diode, which prevents it from conducting, and it has no effect on the circuit at this point. Current from the battery also flows into the inductor. The inductor begins storing some of this energy, and power begins to flow through the inductor to the load, as well as to the capacitor. As the inductor resists instantaneous changes in current flow, the capacitor begins to charge up gradually rather than all at once, increasing in voltage over time. As the capacitor is in parallel with the output, the output voltage slowly increases.

After a set time, the transistor is turned off, breaking the connection to the high voltage DC supply. The side of the inductor that was receiving positive charge from the battery is now seeing nothing. The inductor wants to keep the current flowing, however. Thus, it switches from storing energy from the battery to supplying energy itself. Thus, it develops a negative charge at its input side, and a positive charge at the output terminal to keep the power flowing in the same direction. The negative charge at the input side is also connected to the diode, now allowing it to conduct. With the circuit completed, the energy previously stored in the inductor’s magnetic field keeps the current flowing, stopping the voltage from simply diving straight to zero.

Then, after a period, the transistor is switched back on, and the inductor and capacitor charge up again. The timing of the switching—also known as the duty cycle—is key to how much the output voltage is stepped down. This is the ratio of how long the transistor is on versus how long it is switched off. If the transistor were on 100% of the time, the output voltage would rise to the input voltage once the capacitor was fully charged, and stay there. If the transistor is off all the time, the output voltage would be zero. The output voltage is, in a perfect buck converter, directly proportional to duty cycle. Thus, the desired duty cycle equals the desired output voltage divided by the input voltage. This means that to step down 400V from a traction battery to 12V. we get a duty cycle of 0.03. This means that we turn the transistor on 3 percent of the time, and keep it off 97 percent of the time.

When a buck converter is operating on such a large step down, the off period is very long. as we’ve seen in our example. In these conditions, the inductor can run out of magnetic energy to keep the circuit flowing. When this happens, the capacitor begins to drain itself of energy too, maintaining current flow until the transistor comes back on again. This is called discontinuous operation, though buck converters are also perfectly happy operating at more even duty cycles without issue.

The basic theory behind the buck converter takes some wrapping your head around, but the reality of how they work is even more complicated. There are electromagnetic noise issues to contend with, thermal issues, and it’s important to FOCUS on efficiency too. Engineers optimize all parts of the operation with techniques such as switching the transistor on and off at high speeds. often in the tens or hundreds of kilohertz. This also has the benefit of reducing ripples in the voltage output as the capacitor and inductor charge up and down.

Diodes can also be replaced with transistors switched by external circuitry to mimic a diode’s one-way-valve operation. This is due to the relatively high voltage drop of diodes in the real world. usually 0.3-0.6 volts. which can waste huge amounts of power in a high current application. Transistors can offer voltage drops well below 0.05 volts, saving energy and running cooler, too.

There are numerous, complicated ways to improve a buck converter and numerous ways of configuring them to run in reverse, too but that’s all beyond the scope of this post. But the basic concept at play remains the same. switching on and off a voltage to an energy storage device at a certain duty cycle lowers the voltage at the output.

Mike of the YouTube channel mikeselectricstuff tore down a relatively low-powered unit from a Renault Zoe last year. revealing it to be a densely packed and inordinately complicated device. He points out the obvious features. the large capacitors and inductors made of fat copper bars bent into coils. The video also goes to show the safety measures built into the hardware, like the special high-voltage connectors with extra pins to check that they’re properly hooked up.

These are not cheap components, either. The average alternator in a modern ICE car can output in the realm of 150 amps. Talking about accessories only, electric cars have similar electrical demands to their ICE forebears in this area, so the DC/DC converter must be able to deliver a similar amount of current. This means plenty of fat conductors are required to carry the current, and high power transistors are key. These are often hefty IGBT or MOSFET parts, with bare silicon dies assembled directly onto special thermally conductive boards.

This helps reduce thermal insulation effects from plastic packages on individual components and reduces losses through long component wire leads, too. The DC/DC converter is often built into a single module with the charging hardware, as both need to connect directly to the high voltage battery and both benefit from water cooling their hot electronics.

Thus, the humble 12 volt lead-acid battery remains a key part of almost all modern electric cars, working in concert with a high-power DC/DC converter and 12 volt accessories to provide you with all the usual amenities you expect in a modern car. Technology will continue to march onward, and we may see standards change to higher voltages or new battery types. However, we’ll be relying on low-voltage accessory subsystems for the foreseeable future, and now you know how they work!

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