Bifacial solar panels

[Submariner]

It is my understanding that cycling (depleting/charging/depleting/charging) will not degrade lithium (LFP) batteries like it will lead acid. And also LFP can be nearly completely depleted before charging unlike lead acid. What I am unsure of is what extent of depletion (5%, 10%, 20%...) will result in any noticeable degradation of a lead acid battery. My guess is any, although maybe negligible for a small percentage.

Lithionics, who makes the LFP battery I have, states that when left on a battery charger at 100%, that will lower the available capacity of the battery over time. Which is really the main reason why I stay disconnected from May to Sept. Come September, I have a different routine I do to preserve my LFP's total capacity.

10% SOC is the lowest I can really go. My Lithionics battery will actually power itself off when it hits 10%. I have a push-button override, to turn it back on and can then use the remaining 10%. But the documentation says, below 10%, put a battery charger on it asap, else risk further reduction in available capacity.

LFP prefers to be in a partial state of charge (>10% but less than 90%). FLA/AGM prefer to be on a battery charger at 100% most of the time, to preserve their available capacity.

 

[R23 Kingfisher]

Interesting. Since you have the smart controller my first thought was that maybe that is the state of charge on your phone being displayed but I don't think that is correct. I'd get out the manual and examine the way you have your solar wired considering the number of batteries (house, starter, thruster...), ACRs, etc. Good luck...

 

[GTilley]

Just to close this out for anyone who comes after, the victron app had the ‘discharge floor’ setting at 90%, which is why at 91% the battery indicator showed only one bar. I just went into the settings to change the discharge floor to 10%.

Learning every day!