Alternator damage when charging large LiFePO4 battery banks — myth or real?
This comes up constantly so let me give you the detailed breakdown based on real-world experience in Lydenburg.
The technology: The cost argument for LiFePO4 is now clear. A quality 100Ah LiFePO4 at R5,500 gives you 6,000 cycles at 90% depth of discharge. The equivalent AGM at R2,200 gives you 400 cycles at 50% DOD. Work out the cost per kWh over the lifespan — LiFePO4 wins by a factor of 4–6x. Freedom Won and Hubble Lithium are the SA brands with the best track record. BSL is newer but getting good reviews.
Pricing in SA (2025): R4,500–R7,000 per 100Ah depending on brand and supplier. Get at least 3 quotes — pricing varies significantly between installers and online suppliers.
My setup: 193Ah LiFePO4 battery, 323W solar panel, Victron SmartSolar MPPT 75/15 controller, and a Redarc BCDC1225D for DC-DC charging from the alternator. Total investment: R27,000 all-in. It powers a Dometic CFX3 45 fridge 24/7 and runs LED lights, phone charging, and a 12V air compressor without any issues.
Common mistakes to avoid: Buying mismatched panels and controllers — always size your MPPT for at least 20% headroom above your panel wattage.
Happy to share my wiring diagram or go into more detail on any component. This stuff seems complicated but it really is not once you understand the basics.
3 Replies
The Eskom situation is interesting. My view: the 224 loadshedding-free days is excellent progress but I am not dismantling my solar system. Load reduction on overloaded feeders will continue regardless of Eskom's generation performance. And a home battery system has value beyond loadshedding — cheaper overnight electricity from time-of-use tariffs, backup during faults, and off-grid capability when you need it.
The LiFePO4 price argument is now impossible to dispute. I paid R6515 for a 100Ah unit 19 months ago. At my daily usage pattern, I am nowhere near the 5120 cycle limit. The equivalent AGM cost I would have spent in two replacements already.
The Eskom situation is interesting. My view: the 224 loadshedding-free days is excellent progress but I am not dismantling my solar system. Load reduction on overloaded feeders will continue regardless of Eskom's generation performance. And a home battery system has value beyond loadshedding — cheaper overnight electricity from time-of-use tariffs, backup during faults, and off-grid capability when you need it.