I'm curious about the battery efficiency of LiFePO4 batteries. If I put in 100 units of energy, how much should I realistically expect to get back? I've seen varying numbers—from 90% to 98% efficiency—depending on different sources and conditions. Can anyone shed light on what factors affect these figures and the overall losses involved?
3 Answers
You're right about that efficiency topic! They usually call this "recovery efficiency". I’ve been testing some EVE LF105 cells, which have shown a recovery efficiency of 97% based on my tests. Normally, when fully discharging, I pull out about 104 AH and need around 106-107 AH to recharge. It’s good to note that older batteries will definitely yield lower percentages—I've seen ones as low as 80% because they were nearly 20 years old! It's a reminder of how Lithium batteries just outperform lead-acid options in efficiency.
If you're using Victron equipment, you can typically expect around 70-80% roundtrip efficiency due to various losses in the system, including cable losses and inverter efficiency. For just discharging, I'd say you’re looking at 85-90% efficiency overall. Victron states a roundtrip efficiency of 92% for their batteries alone, which is mainly for DC energy. System design and usage play a huge role too; lower charge and discharge rates help improve efficiency significantly.
That's interesting! But when it comes to just the batteries, it's good to know what their individual efficiencies are, aside from the entire system.
The efficiency of LiFePO4 batteries really varies based on a few factors like discharge rate, quality of the cell, and how old the battery is. Generally, you might get around 92% to 95% efficiency with lower to medium discharge rates. But keep in mind that inverter losses can be significant—think around 10% as a general rule. So overall, if you're charging and discharging, it can drop quite a bit depending on your setup!
Absolutely! Plus, don't forget about charger losses. When I charge from AC, I've noticed I lose about 23% in total.
Yeah, I've seen a datasheet from Victron Lifepo batteries that states a roundtrip efficiency of 92%. That seems pretty reasonable to me.
Good point about the voltage! The Ah in and out should be nearly equal, but you’ll notice a slight drop in voltage, giving that 97% efficiency you mentioned.