How to Charge Your LFP Battery the Right Way

From constant current to constant voltage, understanding how a smart charger talks to your LFP battery can mean the difference between years of reliable service and premature capacity loss.

By
Stephen Burnage
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2
Victron's Smart IP43 Charger uses an adaptive multi-stage algorithm and a dedicated LFP setting to safely manage the transition from constant current to constant voltage charging.(Image/Victron)

If you are thinking of managing a conversion of your own existing, all lead acid system over to one with a Lithium iron phosphate (LFP or LiFePO4), house bank, there are a few things that you need to understand about the charging of LFPs. As we have discussed in previous articles, LFP’s have their own unique characteristics, distinct from both lead acid and other forms of lithium-ion battery. One of the principal distinctions is its charging characteristics.

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Stephen Burnage
Stephen Burnage
Stephen Burnage is a full-time cruiser, having retired in 2017. He left Vancouver, Canada and headed south for warmer climates, on his 1975 Cal 34 sailboat “Moonrise”, in 2018. Since then, Stephen, Moonrise and occasionally his wife Anita, have cruised the West Coast of North and Central America. They are presently in Boca Chica, Panama. Stephen originally trained in the UK as an Electrical Technician Engineer and then proceeded to have a forty-year career, managing high voltage electrical systems around the world. Career highlights include building new power infrastructure on six continents; writing a comprehensive paper on how the North American Power Grid operates (and needs to be rebuilt) and; later, owning and operating his own renewable energy business. Stephen is a joint Canadian and British national and a resident of Chile, with an extended family across the world.

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2 COMMENTS

  1. Great article. At 81 I’m not A “sailor” anymore but run around in a Triton Bass Boat. Way back when I became a Marine Engineer there was no such wizardry. I’m changing over to LFPs for the trolling motor as one goes south. So, I’m now running two lead acid batteries and one LFP in series for a Lowrance 36 volt trolling motor using a NOCO charger. This seems to be woking very well, the charger seems to be the key. I now understand some of the differences significantly better than before.
    Thanks
    Joe

  2. It is not recommended to charge different battery chemistries in series as they have different open circuit voltages, different charge & discharge profiles and different internal impedence. Even charging three LFP’s in series can be challenging (unless you have an external BMS), as imbalances open up over time – better to buy a 36V single pack (managed by a single BMS) if you can. You didn’t say whether your charger is on a lead acid or a LFP setting but you definitely don’t want an LFP on a float or desulfation setting.