What are the benefits of using Lithium batteries in caravans, camping, 4WD or marine?
Because lithium batteries have several advantages, the number of individuals who want to install them in their caravan, camping, 4WD, and marine is steadily rising. Here we have compiled some of the important benefits. Find them below and evaluate whether Lithium solar batteries are worthwhile while you are travelling.
- More usable capacity: With lead-acid batteries (AGM, GEL, Calcium, Flooded) the recommended maximum depth of discharge is 50% to prolong battery life. Meaning if you have a 100Ah lead-acid battery, the recommended usable capacity is only 50Ah. With most lithium batteries such as Invicta you can comfortably discharge up to 80% of its capacity. This means a 100Ah lithium battery would have 80Ah of usable battery capacity.
- Efficient charging: Most lead-acid batteries can only handle a maximum charge current of 30% of their rated capacity to recharge them. I.e a 100Ah lead-acid battery should not receive more than 30 amps. The ideal charge rate of a lead-acid battery is 10-20% of their capacity. They charge quickly during the bulk charging phase which makes up the first 80% of their capacity. The last 20% of the charging phase is called absorption and this generally takes the longest. The charger automatically applies a lower current and a variable voltage to gently finish off the charging phase. Depending on the condition of your battery this absorption phase can take up to 6 hours to complete. Lithium batteries charge more efficiently than lead-acid batteries. Depending on the specs and quality of your lithium battery, they can handle 50-100% of your batteries rated capacity. I.e a 100Ah lithium battery can be charged at 50 amps or more. They also don’t slow down during the absorption phase like lead-acid batteries. This means with the correct size battery charger you can recharge a lithium battery from flat to fully charged within a few hours.
- More cycle life: There are a number of factors that can influence how many times you can cycle / discharge a battery. As a general rule of thumb most AGM / GEL batteries will last around 600-800 cycles at 50% depth of discharge. Lithium batteries on the other hand can be cycled down to 80% depth of discharge for around 2000 cycles. If you only take 50% out of a lithium battery then this number will increase even further. It’s important to know whilst lithium batteries are more expensive up front compared to an AGM battery they will provide a much longer service life in the long run.
- Up to 50% less weight: Lithium batteries weigh approximately half the weight of lead-acid batteries. This can be important to consider if you are an owner of a caravan and worried about your GVM. (Gross Vehicle Mass is the maximum total mass of a fully loaded motor vehicle as specified by the vehicle manufacturer). Alternatively if you are using a battery in a portable solution you might find the lithium battery easier to move around than a heavy lead-acid battery. I.e You have a caravan with 3x 120Ah AGM batteries. In total these would weigh around 90-100kg. At 50% DOD your AGM batteries would provide 180Ah of usable capacity. If you were to upgrade to a lithium battery system, you would find a 200Ah lithium battery to provide 160Ah of usable capacity and would only weigh around 25kg. The weight saving of 60-70kg can then allow for you to carry extra water, fuel etc.
- Safe: The most common lithium chemistry that we use in caravans and off-grid applications in today's market are “Lithium Iron Phosphate (LiFePO4) or Lithium Ferrous Phosphate (LFP). These are the safest lithium chemistries that you can use. Most lithium batteries will feature a built-in BMS which protects the lithium cells from: Over discharge, overheating, under or over voltage warnings etc. The BMS is effectively a sophisticated on/off switch and will disconnect from the lithium cells as a safety precaution. If the BMS turns off you will need to use a lithium compatible battery charger on a very low current setting to “wake the battery up”. SolarBox recommends using a Victron battery charger.
- Can sit unused: Lead-acid batteries must be kept at least 80% charged or ideally higher than 12.6V when not in use. This is because of sulfation. Sulfation is the build-up of lead sulphate crystals that form on the active material of the batteries plates. If the lead-acid battery is left in a discharged state (flat) then the crystals begin to form larger and larger on the plates and as a result your battery will start to lose capacity or could fail prematurely. If the battery does start to sulphate internally you will also notice that the battery gets hot while charging. Lithium batteries are not prone to corrosion or sulfation as their chemistry is not made from lead. In fact, lithium batteries are usually shipped at 50% charged to meet international shipping standards. This means that a lithium battery doesn’t have to sit fully charged at all times if left for weeks or months at a time.