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With winter just around the corner, one of the most common concerns of RVers relates to their batteries. The big question is: which batteries work best in cold temperatures – lead acid (AGM) or lithium? This can be a complex topic, and with the latest release of some interesting new data testing on battery performance, we put together this article to simplify the key highlights for you.
RVs and Battery Power
One of the primary ways an RV is able to provide the convenience, comfort and enjoyment of electrical power while out camping is via the batteries. Traditionally, most RVs come equipped with either regular lead acid batteries or AGM batteries (also lead acid). But over the last few years, lithium batteries have become incredibly popular as a superior power supply.
If you’ve done any research at all on lithium-ion batteries, you would have undoubtedly discovered a limitation – that most lithium batteries generally will not accept a charge in temperatures below freezing. For example, the Battle Born Batteries we installed in our motorhome in 2018 have internal protections that will not allow charging if the temperature drops below 25 degrees Fahrenheit (approx. minus 4 Celsius) and will not resume the ability to charge until the battery temperature exceeds 32 degrees (Zero degrees Celsius).
With this limitation in mind, some consumers have understandably – but incorrectly – come to the conclusion that lead acid batteries perform better in cold temperatures. In this latest study, just released in a detailed white paper by Battle Born Batteries, LiFePO4 lithium batteries dramatically outperformed a similarly sized bank of lead acid AGM batteries.
The experiment – and subsequent white paper report – were produced to answer two of the most common questions Battle Born Batteries reported being asked about lithium battery performance, being:
- Do lithium batteries still work in cold temperatures?
- Can I charge my lithium batteries in colder climates?
Click here for more detail in the white paper report and/or watch the video below.
Key Takeouts from this Battery Experiment
We know this topic can be quite technical and confusing, so here we have simplified some of the highlights we gained from the study, and explain how it impacts you.
- When subjected to a 30amp draw (less than 400watts) at a room temperature of roughly 70 degrees Fahrenheit (21C), the lead acid batteries were only able to deliver 63 of their claimed 210 amp hours of power. Comparatively, the 200 amp hours Battle Born Lithium batteries delivered OVER 200 amp hours of power.
- As the temperatures got lower, the differences between lead acid and lithium became more and more pronounced, with lithium losing very little in delivered power, but the lead acid battery delivering only 32 amp hours at the lowest temperatures tested.
- When drawing a larger amount of power (80amps) the results were even more dramatic. The lead acid battery was basically useless. The 210amp hour battery bank supplied less than ONE amp hour of power. By comparison, the lithium-ion battery continued to deliver 154 amp hours of power, even with temperatures of around 15 degrees Fahrenheit (minus 9.4 Celsius).
The battery experiment: lithium (Battle Born) vs lead acid (AGMs). Credit: Battle Born Batteries
What does that mean for you?
The idea that lead acid batteries are still worthwhile at cold temps was blown out of the water by this study. With so little available power from the lead acids, you would use it up very quickly and it will be difficult to replenish the power since lead acids are so slow to charge, especially when it is cold. Lead acids cannot be charged when super cold either, because of the resistance.
This nullifies the claimed benefit of lead acid over lithium batteries at cold temps.
Even more evidence that lithium is the king of batteries for RV, Marine, or off-grid home systems, even in cold weather. The fact that lithium can still deliver so much power at cold temperatures means that it can use some of that energy to power an external (or internal) heat supply. This, in turn, allows them to stay warm enough to accept power.
In a nutshell, all of this means that you can stay off grid longer, and in more comfort, with lithium batteries.
Benefits of Lithium Batteries
If you have researched lithium batteries, you would already be familiar with the more widely known benefits, including:
- dramatically lower weight
- the ability to use virtually all of the available power
- faster charging rates and
- dramatically longer life spans.
All of these existing benefits were already showing the lithium-ion as superior value, despite their higher initial cost, for those who do extensive RVing unplugged from power. This study clearly demonstrated that lithium also outperforms lead acids, in the one area previously hypothesized as a shortcoming.
We have had lithium batteries (600ah) in our RV for almost 2.5 years now, and they have been an amazing upgrade to our RV lifestyle. With less battery concern, increased ability to camp off grid. As full time RVers, we tend to chase moderate temperatures most of the year, but of course, there are times when we find ourselves in colder weather, and need to pay extra attention to our batteries.
How we keep our batteries warm (safe) in cold temps
Fortunately, in our motorhome, we have a dedicated battery bay, which we’ve been able to keep at a moderate temperature, even in cold weather. Here how we do that:
- We are able to send some of the heat from our furnace into the insulated basement bay where the batteries are stored.
- There is also residual heat transferring through the floor of the living space, and heat generated from the inverter.
- When we are faced with sub-freezing temperatures (we have experienced lows in the teens Fahrenheit (minus 4 degrees Celsius) we put an additional heat source in the battery bay to keep the temperatures warmer. We normally use a 100 watt incandescent bulb in a shop light fixture hanging in the battery bay. This simple light keeps the bay – and batteries – substantially warmer. Don’t use an LED or fluorescent bulb. You need a lightbulb that actually produces some heat.
- We are also able to keep track of the temperature (and humidity) of our batteries using a SensorPush Wireless Thermometer/Hydrometer. We installed in our battery basement bay (and inside the RV). This allows us to wirelessly monitor the temperature and humidity of each area via the app on our smartphones, when in and around the RV.
- When we’re away from the RV, we set up the SensorPush WiFi Gateway, which connects to our router. This allows us to remotely monitor the temperature and humidity via the SensorPush app, no matter where we are. We also set up alerts on the SensorPush to notify us if/when the battery bay hit the minimum or maximum temperatures (or humidity) we have set on the device.
If we planned on spending significantly more time in cooler environments, we would consider investing in specially designed heating products, like the ones offered by Battle Born. If you are buying new lithium batteries, we suggest getting them with inbuilt heat sources, like the next generation batteries from Battle Born.
See our RV lithium battery and power system
If you caught our Ultimate RV Makeover Series, you would have learned all about our RV power and off-grid system in episode 5 and how we used it to power our entire off-grid RV renovation. In the article and video, I go into detail, explaining the benefits of lithium batteries, and why we decided to install them in our motorhome. I also talk about all the elements of our off-grid system, how it works, and what we’ve been able to do with it.
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