Originally Posted by catalinajack
How deep may LiFePO batteries be discharged without reducing their life beyond reason?
Figure 80-90%, and figure on getting at least 2000 cycles out of them, and probably a good bit more. Lab testing consistently yields 2000 cycles with 100% charge/discharge. I've seen no concrete data on longer life spans because it simply takes too long. But even at 2000 cycles, that's about 6 years assuming you cycle every single day, which very, very few boats do. Even half that cycle rate I expect is uncommon. Most people using them are expecting 10-20 years.