time2roll wrote:
Even 13.6 continuous is a bit high. I would stick with what you have.
Also charging the lithium at the absolute max 14.6 volts is overrated and unnecessary.
The 13.2 - 13.6 - 14.4 profile is better. Especially with minimal use due to solar.
Agree.
Unless your 3-stage (13.2v/13.6v/14.4v) lead-cell converter has a lead-cell/AGM equalization mode that goes above 14.6v, there is zero need to upgrade to a so-called "lithium" approved converter/charger.
The so-called equalization mode on many of the Progressive Dynamic units simply reverts to 14.4v bulk mode for about 15 min. every 21 hours, if the battery remains fully charged. Absolutely safe for a 12v lifepo4 battery.
If you leave a 3-stage (13.2v/13.6v/14.4v) lead-cell converter connected to a fully charged 12v lifepo4, it will eventually drop to 13.6v, then 13.2v. Lifepo4 batteries don't like sitting around at a high SOC (13.6v - 14.6v/99 - 100% SOC) for long periods of time, so dropping to 13.2v is good for a 12v lifepo4. 13.2v equates to roughly 70% SOC. The closer you can long-term float at 30-50% SOC the better. Long-term float at 30-50% SOC (13.0v - 13.15v) results in absolute maximum cycle life from a lifepo4.
Most 2-stage lithium converter/chargers will continue to float at 13.6v (99-100% SOC) indefinitely. Although long-term float at 13.6v for long periods of time won't damage a 12v lifepo4 per se, it will reduce the cycle life of the battery a nominal amount (vs. 13.2v).
IMO, the best all-around 3-stage lithium converter/charger would have a 14.6v bulk charge (maximum charge current, minimal charge time, slightly reduced cycle life), a 13.6v absorption, and a 13.1v long-term float (for maximum cycle life).
For those who have a preference for absolute maximum cycle life, a user selectable switch to limit bulk charging to 13.6v, then a 13.1v long-term float, would be ideal.
