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We trialled a modern solid-state Lithium Iron Phosphate battery for our power system setup. By the numbers, this should have been a great fit - lighter and safer than a Gel or Pb-acid battery, with greater resiliance to starting cold. I thought I'd share our learnings here:
This brand of Lithium battery claimed 500CCA and 28 Pb eq. Amp hours storage for their largest 16-cell model, impressive credentials for a relatively compact 3lb battery. In reality, it wasn't to be. The problem seems to lie in the characteristics of the power it supplies, and ability to start a big engine. The battery was not able to delivery the massive current draw to get the 6 clyinder engine turning, past the 'hump' of the first few compression strokes, and then sustain a flow of current at 250A-300A to keep the prop swinging. This is using a 'Bob standard' Skytech Lightweight Starter. On turning the key, the battery would turn over a couple of blades then run out of juice; the terminal voltage dropping down to about 5V-6V at that point. So while the lead equivalent storage capacity and cold cranking amp (CCA) capacity both looked good, either the numbers are overstated in the advertising or the ability of the battery to deliver and use that power wasn't good enough for a six-cylinder engine. So we are changing back to an Odyssey PC680 Gel battery, only 17Ah and 170ish CCA - but massive 680PHCA (pulse hot cranking amps) - and proven in Bearhawks!
Notes on Modern Gel and Lithium solid-state batteries:
Both need to be charged correctly using a balance charger to get full preformance, simply trickle charging won't balance the cells and deliver full restorative charge (from flat), also a Li battery at 60% voltage is considered "flat", a totally empty Li battery cannot be recharged and must be discarded.
This brand of Lithium battery claimed 500CCA and 28 Pb eq. Amp hours storage for their largest 16-cell model, impressive credentials for a relatively compact 3lb battery. In reality, it wasn't to be. The problem seems to lie in the characteristics of the power it supplies, and ability to start a big engine. The battery was not able to delivery the massive current draw to get the 6 clyinder engine turning, past the 'hump' of the first few compression strokes, and then sustain a flow of current at 250A-300A to keep the prop swinging. This is using a 'Bob standard' Skytech Lightweight Starter. On turning the key, the battery would turn over a couple of blades then run out of juice; the terminal voltage dropping down to about 5V-6V at that point. So while the lead equivalent storage capacity and cold cranking amp (CCA) capacity both looked good, either the numbers are overstated in the advertising or the ability of the battery to deliver and use that power wasn't good enough for a six-cylinder engine. So we are changing back to an Odyssey PC680 Gel battery, only 17Ah and 170ish CCA - but massive 680PHCA (pulse hot cranking amps) - and proven in Bearhawks!
Notes on Modern Gel and Lithium solid-state batteries:
Both need to be charged correctly using a balance charger to get full preformance, simply trickle charging won't balance the cells and deliver full restorative charge (from flat), also a Li battery at 60% voltage is considered "flat", a totally empty Li battery cannot be recharged and must be discarded.
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