YOUR COMPLETE GUIDE TO CHARGING A LITHIUM BATTERY - REDARC AND VICTRON RECOMMENDATIONS
One of the most common questions we get at Custom Lithium is straightforward: what do I charge it with? It's the right question to ask. Charging a LiFePO4 battery correctly isn't complicated, but it does matter - and using the wrong charger is the fastest way to shorten the life of a battery that should last a decade or more.
Here's what you need to know, and the specific chargers we recommend.
How LiFePO4 charging works
LiFePO4 batteries charge in two stages: a constant current (CC) phase where the charger pushes current into the battery at a steady rate, and a constant voltage (CV) phase where the voltage is held steady while the current tapers off as the battery reaches full charge. The key numbers for LiFePO4 are a charge voltage of 14.2–14.6V for a 12V system, and an absorption voltage that doesn't exceed 14.6V. Charging with a charger set up for AGM or wet cell batteries will undercharge your lithium - you won't get the full capacity you paid for and it won't do any favours for the lifespan of your shiny new lithium battery.
REDARC recommendations
REDARC is one of Australia's most trusted names in power management and their lithium-compatible products are genuinely excellent. For Custom Lithium customers we recommend:
The REDARC BCDCN1225 or BCDCN1240 - a 25A or 40A DC-DC charger with a dedicated lithium charging profile. This is the unit for anyone charging from their alternator while driving. It isolates your starter battery, charges your lithium aux battery efficiently, and includes a solar input so you can run both your panels and your alternator charge through a single unit. For most dual battery setups in a 4WD or caravan, this is the unit.
The REDARC MANAGER30 or New Alpha 50 - These 30A or 50A DC-DC charger and solar regulator combined. If you're running a more serious solar setup with higher panel capacity, the Manager30 or Alpha 50 handle greater input and gives you more flexibility. It's a favourite among serious tourers and those with larger lithium capacity setups.
The added functions of the Manager, or larger Alpha range (up to 100A constant charge) is the ability to plug in to 240v charge. This can get you out of trouble if you do happen to run the 12v Lithium battery low due to high output over a long period of time, or due to poor weather and low driving times. Simply plug in at a powered site and you're good to go again in no time.
Victron recommendations
Victron Energy is the benchmark for serious off-grid and solar setups worldwide. Their build quality, monitoring capability and flexibility are unmatched. For Custom Lithium customers running more sophisticated systems, we typically recommend Victron systems for Caravans & Complete Off-Grid setups.
The Victron SmartSolar MPPT range - if you're running solar, a Victron MPPT controller is the standard. The 75/15, 100/30 and 100/50 models cover most van and 4WD solar setups, and every unit in the range supports LiFePO4 charging profiles. Pair them with the Victron SmartShunt & the Victron Connect app and you can monitor your system in real time from your phone.
The Victron Orion-Tr Smart or Orion XS 50 DC-DC charger - Victron's answer to the DC-DC charger category. The 12/12-30A or the new Orion XS 50 are the go-to favourites for 4WD and caravan installs. Like all Victron products it's fully configurable via Bluetooth and supports LiFePO4 natively.
If you aren't favouring a large output Inverter/Charger then the Victron Blue Smart IP22 charger - for 240V mains charging, is hard to beat. Bluetooth enabled, and with a LiFePO4 preset. Available from 7A to 25A depending on your needs.
That being said, we highly recommend the Victron Multi-Plus II Inverter Charger systems, with their 12v options of 3000VA output including 120A constant charge to the Lithium battery. Or the 12v 5000VA option allowing a massive 220A constant charge. The future is now. Ask us how we use these systems on our big builds & our own off-grid systems.
The bottom line
Whatever charger you choose, make sure it has a dedicated LiFePO4 or lithium charging profile - not just an AGM or calcium profile. If you're unsure whether your existing setup is compatible, reach out to the Custom Lithium team before you install. Getting the charging right from day one protects your investment and ensures your battery delivers every amp-hour it was built to deliver.