If you’re trying to work out which is the best battery for your RV, you’ve come to the right place. In this comprehensive RV battery buying guide, we explore all the major considerations you need to make when selecting a power product - from RV battery capacity to weight and charge time. With so many products on the market, choosing the right RV battery can be challenging. But it’s absolutely essential if you are to get the most from your RV adventures.
Lithium RV batteries vs lead-acid
The first and most important decision to make is between lithium and lead-acid batteries. In almost every respect, lithium holds the advantage over older lead-acid designs and we believe it represents the most sensible, cost-effective, and efficient means of powering RV electricals.
Lithium advantages include:
- Less than half the weight
- Much higher usable capacity at the same amp-hour
- Full charge achieved up to 6x faster
- Not affected by partial states of charge
- 10x longer life span.
Lightweight RV batteries
Your RV is big and heavy enough as it is. Lithium batteries are typically half the size and weight of traditional lead-acid batteries. Reduce the weight of your vehicle, and you increase the capacity for speed and reduce fuel consumption. Whether you're driving a Class A motorized coach or towing a small teardrop with your automobile, weight is a crucial consideration. All vehicles and trailers have a gross vehicle weight rating or maximum capacity you cannot exceed.
Traditional lead-acid Group 24-31 batteries weigh between 60 and 70 pounds. Lithium batteries usually come in at less than 35 pounds. If you have a bank of eight batteries, those weight savings soon add up. In this example, lithium batteries will lighten your load by a remarkable 280 pounds.
Usable RV battery capacity
Lithium batteries offer a much higher usable capacity at the same amp-hour rating compared to lead acid models. With highly sustainable voltage levels, your lithium RV battery offers 99% usable capacity. Naturally, this enables you to extend your time on the road and enjoy your home away from home for longer.
In many instances, manufacturers recommend discharging lead-acid batteries to 50% capacity at most to prevent premature degradation. So, if you want the advertised expected lifespan from your bank of four 100 amp-hour lead-acid batteries, you only get 200 useful amp-hours before you need to recharge. With highly sustainable voltage levels, your lithium RV battery offers 80% usable capacity and the ability to discharge to 99% without causing damage. Crucially, this means lithium batteries enable you to halve the size of your lead-acid bank and get the same usable capacity.
Significantly faster charge time
Lead-acid batteries have a significantly higher internal resistance, and this resistance increases at a far faster rate than lithium batteries during charging. As a result, charge algorithms slowly raise the voltage, further increasing charge time. With lithium batteries, the lower internal resistance facilitates quicker charging to a much higher state of charge. Practically, this translates to less time running a noisy and polluting generator to recharge your batteries.
Partial state of charge
Partial State of Charge (PSOC) is a common killer of RV lead-acid batteries. As already mentioned, discharging lead-acid batteries beyond 50% of their capacity or not regularly recharging them to 100% adversely affects their lifespan. This can be difficult to manage.
If you rely on solar panels to recharge your batteries, what happens if it is a cloudy day? What if you park up in a campsite that prohibits generator use? Lithium batteries are not affected by partial charging. Expected lifespan and power delivery performance remain the same. Additionally, if you know you won't use your RV for several months, lithium batteries can be put in a storage state (50% charge) for extended periods. There are no adverse effects and they only lose about 3% of their amp-hour capacity for every month in storage.
Cost per cycle
Battery lifespan matters. What is more appealing? A lead-acid battery that needs replacing every two or three years, or investing in a lithium battery that lasts more than a decade? While lithium batteries have a larger upfront investment cost, they also last 10X longer than lead-acid equivalents. This means the true cost of lithium ownership is, at the very least, half of lead-acid. With lithium batteries, you are better off in the long run.
Even the best RV AGM batteries have an effective lifespan of somewhere between 400 cycles at 80% depth of discharge and 800 cycles at 50% depth of discharge. This simply does not compare with lithium battery longevity.
You can compare the costs and other benefits we’ve discussed for yourself in the table below.
To learn more about calculating your energy needs and to find the optimal battery for your application and usage, visit our Lithium Battery Selector Tool.
If you need assistance determining your power needs, take a look at our Battery Bank Sizing article. The table below also contains details of the batteries commonly purchased for use in different classes of RVs in the graphic below. Please feel free to contact us if you need additional help selecting the right batteries for your RV.
