Lithium vs Lead - Shifting Technology and Your Choices

When it comes to off-grid living, RV use, fishing, or camping, choosing the right battery is crucial for a great user experience. Two popular options in the market are traditional lead acid batteries and LiFePO batteries. Let's dive into the differences between the two to help you make an informed decision.

 

What are the key differences between Lead Acid and LiFePO batteries?

Flooded lead acid batteries have been around for a long time and were known for their affordability. However, they can require regular maintenance, including topping up with distilled water, maintaining a full charge (they can be damaged if left discharged), and proper ventilation of the hazardous gasses released during charging (These gasses are poisonous, corrosive, and flammable/explosive).  It is recommended to only discharge lead batteries to about 50%, or you risk sulphating.   This is a chemical process that prevents the battery from recharging/discharging fully, shortening your battery's lifespan.  So, in reality, you only get about half the advertised capacity in your daily use.  Using the battery's full advertised capacity can shockingly drop your number of cycles by up to 75%.   In a daily use scenario, that means they're likely only going to last you a year, maybe two. 

On the other hand, LiFePO batteries are a newer technology that offers several advantages. They have been widely available for several years now, but in the last couple, the prices have fallen dramatically.  This has put them in reach of most users.   They are maintenance-free, lightweight, and have a notably longer lifespan (2-10x more cycles than lead, depending on your use case). One of the largest benefits is LiFePO batteries do not mind being discharged all the way down to 20%, or even 0%, meaning you get every Amp hour advertised!  Often they can go down to 20% over 5000 times before notable degradation.  They also have a higher energy density, meaning they can store more power in a smaller space. So they're physically smaller than the lead equivalent.

The one area, in my opinion, that lead batteries still have distinct advantages, is in extreme cold.   Flooded lead acid (and AGM) batteries operate (albeit with greatly reduced capacity) down to -40°C without any real trouble.   So long as you keep them charged (they'll freeze and crack if discharged fully), they will continue to work.   LifePO batteries can generally discharge down to about -20°C, but need to be above freezing to recharge without damage (Check for low temperature charging protection when purchasing).   However, It is important to remember, that since LiFePO can safely be installed inside, it's easy to move them indoors where the temperature isn't a problem.   Also some modern LiFePO batteries have temperature controlled heating elements built into them, and will prevent charging until they warm themselves up.  More on these advanced features later.

A feature of lithium based batteries that is often overlooked is the discharge voltage curve.   Stay with me, I know that's a mouthful.   Most people are familiar with seeing the output of a battery slowly wither away to nothing, as they use up the charge.  This shows up as your trolling motor spinning slower, or your camper's lights getting dimmer as the night goes on, or your inverter giving you a warning beep when your microwave starts up.

Lead batteries have a fairly linear drop in their voltage output as they discharge. Usually going from around 12.6 Volts down to ~11 Volts as they discharge.  Lithium is quite different.  It will start at around 13.5 Volts, quickly drop to around 13, and then stay there until it's almost fully drained.  This means you get full power from your toys (and your lights) for nearly the full pull of your battery's charge.   It's a little thing, but it puts a smile on most people's faces when they realize this hidden gem of a feature.  

 

What are the benefits of choosing LiFePO batteries for off-grid living or RV use?

LiFePO batteries are a popular choice for off-grid living or RV use due to their durability and efficiency. They can withstand a higher number of charge cycles compared to lead acid batteries, making them a cost-effective long-term investment.

Additionally, LiFePO batteries have a faster charging rate and are safer to use, as they don't produce dangerous/flammable gasses, and therefore are less prone to catching fire. This added safety feature is crucial, especially in remote locations where immediate assistance may not be readily available.

Lets examine a traditional setup using 2 deep cycle 6V batteries of ~230 Amp Hours each.   The two batteries together give you approximately 1.4kWh of usable energy (50% Depth of Discharge).  Enough to run a few lights and the furnace in your camper for a weekend getaway.   These batteries weigh 126lbs (57.2kg), and if you take good care of them, they should last you about 3-5 years.

Now, let's look at the equivalent LifePO setup.   You buy 1 battery with 230 Amp Hour of power (~2.8kWh).  It's enough to run the camper's lights, furnace, and charge a few devices for a long weekend.   Wanna know the best part?   It's only  28kg!  You've doubled your usable power AND reduced your weight by half.

The benefits only go up from there.  You can get models with built in Bluetooth so you can see, from your phone, exactly what your batteries are doing, and how much charge is left in them.   Add solar or external chargers into the equation, and it becomes a great troubleshooting tool.

A huge benefit, that I mentioned earlier, is that they charge faster.   Unlike lead batteries that start off charging strong, and then slowly wither down to only a few amps, LifePO batteries will pull the full power of your charger until they are over 80% charged, at which point it will start to slow down a little, but still not nearly as much as lead.

 The list goes on.   If you've ever had a flooded lead battery bank, you know you have to top up the cells with distilled water, and monthly you are supposed to "Equalize" the batteries by purposely over charging them for a few hours.  This is essential to maximizing the life of a lead batter bank, especially in a daily use scenario like a solar powered house, or cabin.   Lithium batteries don't generally need this extra chore.   In fact, the BMS inside quality LifePO batteries will "Active Balance" the cells automatically, every time you charge the batteries back up to full.   Not all batteries include this feature however, so be sure to check the manufacturer's spec sheet to ensure it does when making purchasing decisions.

Lower Ownership Costs of LiFePO Batteries

While LiFePO batteries may have a slightly higher upfront cost compared to flooded lead acid batteries (currently it's only about 15% higher), their significantly lower ownership costs, over time, make them a far superior choice for most people. With fewer maintenance requirements, a longer lifespan, and far more usable energy, you'll save a ton of money in the long run by choosing LiFePO batteries for your off-grid power needs.

 

Safety First: A Note on Battery Handling

Regardless of the type of battery you choose, it's essential to prioritize safety when handling and installing batteries. Always follow the manufacturer's guidelines for proper installation, maintenance, and disposal of batteries to prevent accidents and ensure optimal performance.

There is a lot of confusion around lithium batteries, and their perceived safety (I hear the term "explode" pretty often). 

It's important to recognize that there are many lithium based battery technologies.   Lithium Ion (like that often used in laptops, cell phones, etc) does have an increased risk of fire, when compared to Lithium Iron Phosphate (LifePO4) batteries.  When damaged, or allowed to heat up too much, lithium ion ignite violently, and burn incredibly hot, further damaging themselves and other cells around them.  However, LiFePO batteries do not suffer from this "thermal runaway" condition, where they suddenly combust when damaged. Don't get me wrong, care should always be taken to prevent damage to LiFePO batteries (they can still rupture and be fairly violent), but they are not known for being a fire hazard, and do not self-sustain flame.

Their safer chemistry, along with integrated Battery Management Systems (BMS) that are built into the batteries, often have many protective features to keep the battery safe from things like accidental overcharging, short circuit, or overload.  Features like this make them arguably more safe than the traditional lead based batteries.   They not only help protect you from things like accidental wiring errors, but they also help maximize the lifespan of your battery, saving you money.  It's a good idea to always check for these features when buying a new LifePO battery, to ensure the safest experience possible.

 

Frequently Asked Questions Surrounding LiFePO Batteries.

Q: Are LiFePO batteries compatible with solar setups?

A: Yes, LiFePO batteries can be easily integrated into existing, or new, solar setups with the appropriate connectors and converters. They are a proven and versatile option for renewable energy storage.  This works for everything from cabins to RVs to tent trailers to a little DIY solar backup you keep in the garage for emergencies.  With their smaller size, and weight, they are excellent for this purpose.

Q: Can I use LifePO in my RV without changing anything else?

A: Chances are good, yes you can.   Most recreational vehicles come equipped with the ability to plug in to "Shore Power" when available, and this activates an onboard "Converter" (fancy word for charger).  This charges your onboard batteries back up, so you're ready to go on your next off grid adventure.  The catch is, that the older style "Charge Converters" (or "RV Converter" as they're sometimes called) are often setup only for lead acid charging voltages.  LiFePO uses a slightly higher charging voltage, so your new batteries won't charge to 100% full.  This actually gives the batteries an even longer lifespan, but means you're not quite getting your full advertised power.  The choice to run "as is" is yours, however, new converters are often available around $150 (or less), are fairly easy to install, and will be compatible with lithium based batteries for full charging.   If money is tight, you can always upgrade your charger/converter later.

Q: Why would I want extra features like Bluetooth or Heating?

A: Bluetooth offers a huge advantage with the ability to "see" what's going on inside your battery.  See exactly how much charge is left, or see how much energy you are drawing from (or charging into) your battery.   This can be accomplished with a "Battery Monitor" (aka "Shunt") as well, which gives you a remote screen (wired) that you can place in a convenient location. Some batteries are now including an onboard LCD screen that communicates with the BMS and shows you exactly what's going on.  So the choice is yours, but I always recommend some form of indication to make troubleshooting your system easier, as well as giving you peace of mind when you're away from shore power.

Features like self heating offer the ability to use the batteries in more extreme cold environments, without risk of damaging them.   This protects your battery, plus gives you better enjoyment of your investment.  Self heating is a great option for off grid cabin solar, or where you are trying to recharge during the cold weather.  Where possible though, you can always insulate or move the batteries to a warmer location.

Q: How do I dispose of old batteries safely?

A: RECYCLE THEM!  Don't ever throw them in the garbage, or your curbside bins.   Both lead and LiFePO batteries are fully recyclable. It's important to recycle old batteries properly to prevent environmental harm. Many municipalities offer recycling programs, or you can contact your local waste management facility for guidance on safe disposal methods.  There is also an ever growing DIY culture of people who will repair, reuse, and repurpose old batteries.  You can likely give it away on marketplace (or similar sites), if you don't want to deal with the recycling.  Just never throw them in the trash as they will be damaged in the trucks, and can cause safety issues for the workers/facilities.

 

In Conclusion

When it comes to choosing the right battery for off-grid living, RV use, or activities like camping & fishing, LiFePO batteries stand out as a reliable, safe, and cost-effective option. Their advanced technology, longer lifespan, and lower ownership costs make them a smart choice for powering up your adventures.