Fast Charge

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), there are significant recharge benefits to switching to a LiFePO4 dual-battery setup.

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 that are 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 full 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 simply 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 to last more than 5 years!
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. Incidentally, both setups have a similar overall cost and useful capacity.

 

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.

What’s more, 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 rate of recharge, there are several other pros and cons to consider.

LiFePO4 PROS:

    • Charges faster
    • Significantly lighter (important for portable systems)
    • Can be deeply discharged without greatly affecting battery life
    • Has a longer life span

LiFePO4 CONS:

    • Heat sensitive
    • Costly initial expense
    • Requires a unique charging algorithm
    • Cannot be charged directly from your vehicle’s alternator
    • Can have a much lower current limit, making it unsuitable for high-current applications, i.e. winching and engine cranking

SUMMARY

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

That said, it’s really 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, or do you tend to stay in 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.

 


NLDC-25 DUAL-BATTERY ISOLATOR & CHARGER

The National Luna NLDC-25 is a 25A DC-DC charger and dual-battery isolator. The unit features a 6-stage charging algorithm that’s suitable for all lead-acid batteries, as well as automotive Lithium-Ion batteries.


NLDC-40 DUAL-BATTERY ISOLATOR & CHARGER

The NLDC-40 is similar to the NLDC-25 in terms of features; however, the NLDC-40 has the added benefit of a faster recharge cycle, 40A output, as well as the ability to accept an additional power source (e.g. wind turbine).


DC25 POWER PACK

The National Luna DC25 Power Pack blends the convenience of a ‘plug & play’ portable-battery system with the performance of a DC-DC charger, lithium compatibility, and MPPT solar regulator.

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