So I am guessing you have been hearing all this talk about the wonders of lithium batteries for RVs. Have you finally thought this might be the right time to upgrade your camper? Perhaps you have decided which of the 5 levels you want to have for you camper’s electrical system but don’t know if lithium is worth the price? Well, you might be right. For a long time, RV lithium batteries have been too cost prohibitive to make the leap. In the past few years, a good quality 100Ah LiFePO4 drop-in replacement has been well over the $1,000 mark whereas a 225Ah AGM battery can be had for about 1/3 the price. But with more manufacturers competing for your business and quality of components continually improving, prices have dropped and quality has improved. The time might be finally right to make the leap. If you factor in the longevity of well-maintained lithium cells, lithium batteries in fact cost much less than AGMs when amortized over its lifetime.
In this article, I will try to break down the reasons why this is the right time to finally take the plunge and all of the details you should be aware of to choose the right parts. Keep in mind that I will be using the terms ‘lithium’, ‘lithium ion’, ‘LiFePO4’ sometimes interchangeably but will be specific about the actual chemistry when necessary. Likewise, ‘lead-acid’, ‘AGM’ and ‘Gel’ will also be used to refer to the traditional battery type.
Table of Contents
- Why Should You Upgrade To Lithium Batteries Now?
- 12-Volt or 24-Volt?
- What Type of Battery Chemistry Is Right For Me?
- Components and Features of a LiFePO4 Battery Pack
- How To Choose A LiFePO4 Battery
- Surveying Your Current Electrical System
This is quite a long article with a lot of information in it so feel free to use these table of contents links to jump between each section as you find this information useful. All of the information I am posting here is from my more than a decade of full-time traveling in campers with thousands of nights of boondocking all over the world in all seasons and weather conditions. But I do have to say this, I am not a professional electrician. These are my educated opinions from my own experiences. Follow at your own risk.
Why Should You Upgrade To Lithium Batteries Now?
I realize some of you may not be exactly sure that you are ready or need to make this upgrade. Whether or not cost was the reason that held you back, there are other reasons why you might not find the upgrade necessary. If that is you, I want to give you some other reasons to consider the change.
- It is safe – For a long time people have been concerned about the safety of lithium cells. There have been instances of battery packs catching on fire reported on the news. It is true that this is a risk and the FAA has even implemented limits on how big of a battery you are allowed to bring aboard an airplane. But depending on the specific battery chemistry, thermal runaway from a failed lithium battery may not be a problem. Specifically Lithium Iron Phosphate (LiFePO4) batteries have been proven to have minimal risk when it comes to catching fire. We will talk about these batteries a bit later as they are the ideal cell type we will be recommending. Other types of lithium cells have also come a long ways to avoid its potential dangers. With proper assembly techniques, individual smaller cells can be isolated and fused as they have been done in electric vehicle’s battery packs to limit its potential for thermal runaway.
- It is becoming more affordable – With more people willing to make the leap to using lithium in their campers, lots of manufacturers have come online to build replacement batteries specifically for RVs. With more competition, we now have lower prices. Of course we will still see prices continuing to fall in the future but I believe right now it is at the point where mass adoption will happen worldwide especially since we are starting to see some RV manufacturers like Winnebago using them in their campers.
- It is light – Lithium batteries have much higher energy density than their lead acid counterparts by weight. For the same amount of usable energy, a LiFePO4 cell will only weigh a quarter of that of a lead acid. You will benefit from having a lighter vehicle for better fuel economy or having as much as 4 times the power capacity with the same amount of weight.
- It will power your RV for longer – Because it is so light, having more power is often the result of upgrading to lithium. In a lead-acid battery, the recommended DOD (depth of discharge) is no more than 50% of its rated capacity. With regular discharge of more than 50%, the battery will degrade and lose its ability to recharge much sooner. Lithium, on the other hand, can be discharged much more without any harm. To maximize your lithium batteries cycle life, charging to no more than 90% and discharging to no less than 10% is recommended. That means you will get around 80% of your batteries rated capacity. That means you will be able to run your RV for 60% longer using a LiFePO4 battery at the exact same rated capacity as an AGM.
- It will last a long time – One of the biggest benefits for upgrading to lithium is how many charge cycles they can endure without any noticeable signs of decreased capacity. With high quality AGM batteries at around the 500 cycles range, a heavily-used AGM will not even last 2 years without degradation if it is completely charged and discharged daily. A LiFePO4 on the other hand has the potential to cycle between 4,000 to 5,000 times. That is an improvement by a factor of 10. You might not even keep your camper for that long.
- Less voltage sag under load so its better for your components – Another benefit of lithium battery chemistry is that the discharge curve is not as linear as lead acid. That means you will be able to hold a more constant voltage throughout a single charge without the voltage dipping too much. Why does that matter you say? Well, it is important that sensitive electronic equipment that uses DC power from a battery receives adequate power to prevent it from being damaged. In lead acid batteries, a heavy load will cause the voltage to drop significantly. This is less pronounced in lithium batteries so your electronics and other electrical appliances will be happier.
12-Volt or 24-Volt?
If you have done a big of research on lithium batteries, you have probably come across the 12-volt vs. 24-volt conversation. I know there are several things that may be confusing about switching to a lithium setup but this one we should get out of the way first. Do you need a 12 volt or a 24 volt system?
Well, for the most part, if you are upgrading from an existing lead acid system, you will most likely want to stick to a 12 volt lithium battery. Unless you are planning major changes and overhauls across your electrical components, a 12-volt lithium will be the easiest way to upgrade. Any of your existing 12-volt devices will work as it currently is without the need to do any sort of rewiring. Lights, fans, USB plugs, RV appliances all come standard with 12-volt DC power as the requirement.
So why would someone consider a 24-volt battery setup? Well, there are basically 2 main reasons. One reason is to be able to use smaller gauge copper wiring. According to Ohm’s Law, with higher voltage you will have lower amperage running through your wires. The lower the amperage, the thinner your wires can be without any overheating or voltage drop across the wire. This makes the biggest difference when you need to run long cables to connect to things like solar panels, DC-DC chargers and power inverters. 24-volt would also be a good idea if you are planning to use a large power inverter to provide your camper with AC power like you would have in a house. I will talk more in depth about power inverters later in this article but generally speaking, 24-volt power inverters can have efficiency gains over a 12-volt one and will require smaller gauge wiring. If you do decide to go the 24-volt route, keep in mind that a 24v-12v step down converter might be required to keep things like lights, fans and water pumps running without fail. They will not work natively with 24-volt, it will most likely destroy the component when the higher voltage is applied.
So I would recommend, as a general rule of thumb, that if you are unsure whether or not to use 12-volt vs 24-volt, stick with 12-volt. It will be a much simpler system to set up especially if you are upgrading from a lead acid battery.
What Type of Battery Chemistry Is Right For Me?
This is the section where I get a little bit more technical but I will try to keep things simple so it is easier to understand. In the spirit of simplification, I will categorize lithium ion batteries as a catch all that describe all lithium cells that have a nominal voltage of 3.6 volts such as Lithium Cobalt and Lithium Nickel Manganese. Lithium Iron Phosphate will be the second type with a nominal voltage of 3.2 volts. These 2 categories are important because they differ in several important areas.
- Lithium Ion (Li-Ion)
These are the types of batteries that are most often used in products like phones, laptops and electric cars. They are also used in many of the standalone all-in-one battery banks like the GoalZero and Jackery products which I will talk about a bit later in this post.
- Pros – These are known for their very high battery density. You can pack the most amount of electricity in the smallest space and weight. They usually come in the form of cylindrical cells with the most popular being the 18650 form factor. These are much more popular as they have been used for a long time and can often be salvaged from used battery packs used in modern electronics.
- Cons – These are the types of cells that have the potential issue of thermal runaway. This means that the chemistry of these cells have the tendency of catching fire when the positive and negative terminals are accidentally shorted. Also these batteries can provide very high discharge rates which is great for demanding uses like in electric vehicles. However with excessive discharging, they can overheat and thermal runaway can also occur. One of the biggest issues with these batteries are actually their nominal voltage. Each cell is rated as 3.6 volts. To get the desired 12 volt range in order to build a drop-in replacement for lead acid, connecting 3 cells in series will give you slightly too low of voltage while connecting 4 cells in series will give you too high of voltage. A voltage regulator sometimes can be used to keep the power output constant but it will decrease its efficiency and add complexity to the system.
- Lithium Iron Phosphate (LiFePO4)
These types of lithium cells have been growing in popularity in recent years and is what most battery manufacturers are using for RV drop-in replacements.
- Pros – LiFePO4 chemistry is more stable and has a far lower chance of thermal runaway when overheated or shorted. Also the nominal voltage is lower than the other lithium type at 3.2 volts which means connecting 4 cells in series will give you the ideal voltage for a 12-volt RV system. This chemistry is also much more durable and can have 3-5 times more charge cycles when proper care is taken.
- Cons –The biggest downside is their battery density. LiFePO4 by weight has only about 2/3 of the energy density as compared to other Lithium-Ion batteries. However, there is still a very significant weight advantage over traditional lead-acid types.
With the pros and cons of the different chemistry out of the way, you hopefully will have a good idea of what might be best for you. Even though Lithium-Ion cells might pose a higher thermal runaway risk, there are ways to be able to contain and minimize the danger if built properly. But if you are reading this article, you are likely a relative beginner and your best bet is to stick with the safer and easier to use Lithium Iron Phosphate batteries.
Components and Features of a LiFePO4 Pack
Besides just the actual cells that provide electricity, a lithium battery pack that is compatible with your RV has various components that provide safety and maintenance features. These components are equally as important as the cells themselves and will make all the difference in how your new battery performs, how safe it is and how long it lasts.
- Cells – This is the meat and potatoes of a battery pack. Getting high quality cells with accurate rating is important. Not all manufacturers are rating their cell capacity properly. A good manufacturer will often under rate the capacity to avoid overstating them. Buying them from a supplier that is using new and matched cells will make all the difference in its longevity. When the age and cycle life of cells in a pack are matched, you will get the most capacity and lifespan out of them.
- BMS – Arguably this is the most important component in a lithium battery pack. BMS stands for ‘Battery Management System’. It is here where software on the circuit board, as well as specifically designed circuits, will keep track of the input, output, balance and sensory mechanisms to prevent your cells from being damaged. A BMS will prevent over-charging and discharging of your lithiums cells. It will also try to keep each cell properly balanced from each other. That means it will try to keep the voltages as close to each other as possible so no single cell gets damaged during use. A good BMS will also cut the battery off from use when it is over or under its operating temperature limit.
- Active Battery Balancer – This component is not always present as a standalone item. BMSs often have battery balancing features but they may not do what is called ‘active’ balancing. A passive balancer will simply drain the cell that is too high in voltage by dissipating it as heat. An active balancer will transfer electricity from a higher voltage cell to a lower voltage cell with in the pack with minimal loss.
- Insulation – Often the exterior casing of individual cells are part of the negative terminal. So that means you are going to want to insulate them from each other to prevent any potential issues. Also when multiple cells are connected as a pack, they are usually bound with some kind of heat shrink plastic or tape. Having some insulation between them will also allow the cells to expand and contract a bit as they naturally will during the charge and discharge cycle.
- Bus bars and Terminals – To connect the cells together, there are terminals on each end of the cell and metal bus bars connecting them. These will connect cells in series within one battery pack as well as connecting multiple battery packs in parallel when someone wants to increase their overall capacity. It is important that these connections are solid and properly-sized conductive metals are used such as copper plates.
- Enclosure – Lastly, the entire battery needs to be protected in an enclosure to prevent other objects for damaging it during use. Ideally a non-conductive material is used to minimize shorts. Even better, a fire proof enclosure will also keep any potential hazards at bay if the worst-case scenarios of thermal runaway happens.
How To Choose A LiFePO4 Battery
We are finally at the part of the article where we can talk about what to buy. It is important to get some baseline knowledge of the upgrade you are doing before making the choice into what is the best product for you. There are essentially 4 different ways to do this varying in complexity and technical skills required. I will start from the easiest to the most difficult.
- Complete Stand-Alone Battery System – This is by far the easiest system to install. Companies like GoalZero, MaxOak and Jackery are all popular brands who make complete standalone lithium battery systems. They come complete with chargers, inverters and outlets all built-in to the enclosure. Some of these are better suited for RV use but some are mostly made for portable power needs. These are extremely convenient but often come with shortcomings. Some of the biggest shortcomings are having limited capacity for expansion as well as their compatibility with solar charging. These are relatively expensive but for someone with a small DIY campervan with minimal needs it could be the ideal product to quickly and conveniently put together an electrical system.
- Factory-Assembled New Batteries – For most people, this will be the way to go. Some of the most popular companies that sell these are BattleBorn, Victron, Renogy and Relion Batteries. They come complete in an enclosure with everything as a drop-in replacement to an existing lead-acid battery. The most important thing to look for when you choose one of these is whether or not your battery compartment is inside versus outside. Lithium batteries are more susceptible to hot and cold temperatures. If your battery compartment is not temperature regulated, you can destroy the battery if it does not have a low temperature cut off feature in the BMS.
- Build Your Own from New Cells – This is a bit more advanced for those of you interested in customizing exactly the type of battery you want. It can also be a way to build a high quality battery at a significantly lower cost. There are several types of cells you can buy to assemble your own battery. Cylindrical and prismatic LiFePO4 cells are the most popular. Depending on what you choose, how they are assembled together will be different. As compared to a factory-assembled new battery, you can build a comparable new battery with good components at around half of the cost.
- Build Your Own from Used Cells – Building from used cells is the most cost effective way to switch to LiFePO4 in your RV. This is also the most complicated process as used cells are often of different manufacturer dates and unmatched. This poses an issue as it can lead to over charging and discharging of cells in your bank. The method to decide which cells will work together involves individually testing each one for capacity. It is a time consuming process and requires a lot of know how. But it is the cheapest way to build a usable LiFePO4 battery for your RV. There are many websites and YouTube channels besides ours that will go into much more detail about each of these processes. If you are on a budget but determined, you can go this route and still have a very good setup.
Surveying Your Current Electrical System
Once you have decided which way you are going to go with acquiring your lithium upgrade, you need to know a few important things. Deciding how much capacity you need is one of them and depending on what goals you are hoping to achieve with the upgrade, that will make a difference.
How you use your RV is also important when it comes to deciding what capacity is ideal for you. Some people have said that you can always use more batteries. That notion is true generally speaking. But if you are a full-time traveler like ourselves, you might want to think the process through a bit more. It is important to me that my charging capacity is matched with my storage capacity.
Take solar for example, we often stay in one boondocking place for extended periods of time. If I used more than I am able to generate daily and run a power deficit, I will eventually run out of power and it would take multiple days of electrical rationing to replenish it. In that case, I either don’t have enough solar panels or need to decrease my consumption which means the extra battery capacity becomes less useful. For a more in-depth look at how to size your solar system to match your battery capacity, check out this article.
When an RV is used for everyday living, having the ability to top off your batteries each day gives you a peace of mind so you don’t have to run a generator, use the engine to charge, or search for a plug. If you are a weekender and the RV sits idle most of the time, then it is not a problem to arrive home empty and just charge up before your next trip. Here are some things to consider when deciding how much capacity you need.
- Calculating total daily consumption – It is best to calculate your consumption based on watt hours instead of amp hours. Watt hours give you an absolute, unambiguous number of how much power you need. Use a watt meter for each of your appliances to see how much each item draws. Estimate how many hours a day each appliance is used and add them all together. Whatever battery you use, it should have its rating in watt hours. Make sure your total consumption is under 80% of the listed capacity. For example, if your battery is rated for 1,200Wh, make sure you are not drawing more than 960Wh per day from all of your devices.
- Decide the amount of max current draw for all appliances – Knowing how many amps you will draw at a maximum is also important especially if you are building your own battery pack and choosing your own wires and BMS. Making sure your wires are properly sized and the BMS can handle the current draw. It will make sure your BMS does not trip and go into safe mode. Under normal conditions, you should be fine with regular RV appliances. But if you are venturing into high current draw territory like microwaves, toasters, hair dryers and other items you might run through a large inverter, make sure you are not exceeding the capacities of your battery components.
- Where You Plan to Install Them – As mentioned above, your battery location will have an affect on whether or not you will need to worry about extreme temperatures. Batteries do not like extreme temperatures and lithium batteries are especially sensitive. A good BMS will have a low temperature sensor and cut off your ability to charge and discharge it when it reaches below a predetermined setting. This is in place to save your investment because a lithium battery will be irreversibly damaged in these conditions. But this can also be quite a hassle as not having any power to your RV in subzero temps is not my idea of the good time. Whenever possible, try installing your lithium battery inside the RV where the temperature is regulated. Alternatively a tank heating pad can be used on a thermostatically controlled switch to automatically turn on when the batteries drop below a certain temperature.
- Upgrading Your Chargers – Be aware that by simply installing a drop-in replacement does not mean everything will work without further changes. For the most part, your output side will work as before. Lights, fans, pumps should all be happy with the voltage and current coming out of the new battery. But the input side on the other hand will need some attention. Lead-acid batteries do not charge using the same charging profile as a lithium battery. Make sure the charger that you are using has the proper charging profile that matches the battery of your choice. Here are some options that work with most LiFePO4 batteries.
- DC-DC – With lithium batteries, it is important that you choose a DC-DC charger instead of just wiring your alternator directly to the system with a relay. The alternator will not fully charge a lithium bank and has the potential to damage it without a smart profile. Select a proper charger with the correct charging profile for the job and use properly sized wire based on how much current you plan to push through them.
- Solar – Most solar charge controllers sold these days have LiFePO4 charging profiles pre-programmed. Some may require you to look at the manual and turn dip switches to set them while others have graphical interfaces. Refer to your manual for specifics.
- Shorepower – Depending on the year of your camper and where the converter charger comes from, you might need to upgrade your shorepower charger as well. You can also opt for an expensive all-in-one system like a Victron Multiplus or something portable and simple like a NOCO Genius. There is one that will work for any budget.
- Other components that you might consider upgrading – Besides the charger which is a must have upgrade if your old one is not lithium compatible, here are some other components that might be nice to also upgrade but not totally necessary. You might already have some of these components in your current system as they are not exclusively for lithium batteries.
- Battery monitor – Because lithium batteries don’t have as linear of a voltage curve as lead-acid as the capacity decreases, it is not as easy to know just how much power you have left by simply looking at the voltage. A shunt-based battery monitor is a nice tool to have so you can know exactly how much power you have charged and discharged at any given time. It is also a good tool to be able to know how much power each individual appliance draws.
- Wires, breakers and fuses – With a lithium battery, you will most likely have more capacity to draw more current to use more power hungry electrical appliances. People often use things like induction stoves and electric water heaters after they switch to lithium. Be aware that your existing breakers, fuses and wires might not be set up to handle that rate of consumption. Take a look at each wire and make sure it is able to handle the power you plan to draw through them. Fuses will blow, breakers will trip and under gauge wires can catch fire
- Inverter – With more capacity you might also consider upgrading your inverter so you can run bigger AC appliances. An induction stove top can draw as much as 2,000 watts so if you are planning to use such an appliance, a bigger inverter might be in your future.
- Components that are nice to have with lithium – One of the reasons some people switch to lithium is to avoid the need for fossil fuels like propane. That means you will no longer be able to cook with your propane stove or heat with your propane furnace.
- Electric cooking equipment – An electric induction stove top is a nice efficient appliance. Even though it draws a lot of power, a large enough battery bank with proper sized components and inverter should have no problems with it. Just be mindful to keep your cooking times short so you don’t drain your batteries too quickly.
- Electric water heater – Without propane, you will also need to rely on alternate ways of heating water. Electric water heaters can have very high power draw but with limited use, they can be helpful to add some comforts of home into your RV without burning fossil fuels.
- Diesel/Gasoline heater – Heating is one of those things that electricity can not quite solve at the moment in an RV when off grid. For a diesel powered vehicle, a diesel heater makes a lot of sense because it will just sip small amounts of fuel from your vehicle’s fuel tank and provide a nice dry heat. Although not as common and slightly less efficient, there are also gasoline versions of these dry air heaters.
- Air conditioning – One of the holy grails of off-grid RVing is the ability to run your air conditioner when boondocking. Although possible, this is for those who have the space for large battery banks and vast roof space for many, many solar panels. I would not consider using an air conditioner off of batteries unless you are able to install north of 500Ah of lithium batteries and around 1,000 watts of solar panels.
- Components that still will not work with lithium
- Electric heaters – Well you are probably thinking that if air conditioning is possible, then everything else should work! Well, yes and no. Of course you can use an electric heater technically, but unlike air conditioning which is used during the day when your batteries can be replenished by the sun, heaters are usually used at night. With such a high consumption rate and the need for it to be constantly on for hours at a time, running an electric heater on battery power is still not really a good idea.
I hope this article has provided you with the knowledge you need to take the plunge into the world of lithium batteries for RVs. We have come a long way technologically and now is the best time ever to be living off the grid and on the road. If you have any further questions about full time travel or off grid living, sign up to receive our Freely Roaming Newsletter below and subscribe to our YouTube channel so you can learn more about this lifestyle and make your dreams a reality.