Is it time to ditch your lead-acid battery for lithium-ion technology?

While some overland travellers have migrated away from lead-acid batteries in favour of Lithium Iron Phosphate (LiFePO4), others are not yet convinced of the economics.

Although it may be true that the higher costs of a LiFePO4 auxiliary battery make it harder to justify in a vehicle-based application (where the system is only used a few times a year), switching to a LiFePO4 dual-battery setup offers significant recharge benefits.

Economics aside, the real question is: How much better performing is LiFePO4 when compared to lead-acid batteries? And does that performance justify the higher upfront costs?

BATTERY TESTS

Boasting a range of DC-DC chargers that are all lithium, AGM and wet-cell compatible, National Luna recently tested three battery options commonly used within the leisure market. We conducted these tests by discharging each battery type by 70Ah and then recorded the recharge performance using our 25A and 40A DC-DC chargers.

As shown in the graphs below, the LiFePO4 battery features a longer ‘Bulk’ charging stage in relation to its shorter ‘Absorption’ stage. This is thanks to lithium having a better ‘Conversion Efficiency’, which means the LiFePO4 battery reaches its total capacity in a far shorter period.

An argument for lithium: Technically speaking, you could consume the entire capacity of a LiFePO4 battery at night and recharge the battery (to a full state) on a 2-3 hour game drive the next day or a short trip to your next campsite. Even when doing this every day, a LiFePO4 battery promises a significantly greater lifespan.

The extra 15 amps of the NLDC-40 help the LiFePO4 battery reach a full charge in less than 2 hours. It’s also worth noting that a 40A DC-DC system coupled to an AGM battery has a similar recharge time to a 25A DC-DC system coupled to a LiFePO4 battery.

In contrast, the recharge performance of the wet-cell and AGM batteries is hindered by a disproportionately short ‘Bulk’ stage in comparison to a longer ‘Absorption’ stage.

Moreover, the extra 15 amps of the NLDC-40 help the LiFePO4 battery reach a full charge in less than 2 hours. Needless to say, a rapid recharge cycle is supremely practical in terms of driving times and how you plan your road trip.

PROS & CONS

Of course, only you can decide if the above data justifies a migration, but aside from the recharge rate, there are several other pros and cons to consider.

LiFePO4 PROS:

- Charges faster
- Significantly lighter (important for portable systems)
- It can be deeply discharged without overly affecting battery life
- Has a longer lifespan

LiFePO4 CONS:

- Heat sensitive
- Costly initial expense
- Requires a unique charging algorithm
- Because the battery can accept a much higher current than the alternator can deliver, a lithium battery should never be recharged directly from the alternator. Doing so could permanently damage your vehicle’s charging system.
- Highly sensitive to overcharging (above 14.6V), which is why your chosen lithium battery should include a Battery Management System with overcharge protection. Note: Some intelligent alternators may reach voltages as high as 16V in certain weather conditions.
- Lithium batteries often have a much lower current limit, making them unsuitable for high-current applications like winching and engine cranking in an emergency.

SUMMARY

Considering the above points, it’s clear that the decision to adopt LiFePO4 technology has less to do with economics and more with the convenience of having a fast-charging dual-battery system.

That said, it’s a personal question of whether the performance benefits of a LiFePO4 battery are enough to overlook the initial costs of the newfangled technology.

However, it should also be noted that the integration of a solar panel will also greatly influence your decision, as well as your camping habits:

Do you typically drive long distances between camps?
Do you move around a lot?
Do you tend to stay at one campsite for a few days?

What’s more, not all DC-DC chargers support lithium technology, so make sure your DC-DC unit is lithium compatible before you make any changes to your dual-battery setup.

Fortunately, no matter which battery technology you opt for, the following National Luna products all support: lithium-ion, LiFePO4, AGM, Calcium and wet-cell batteries.