LiFePO4 best practices

[NahanniV]

Originally Posted by SV THIRD DAY

Hi JM

I I have a few Blue Sky 2000E controllers.
Yes, once the charger sees 13.8V on the battery bank. So once my batteries get to 13.8v, no more amps flow into the battery from the solar controller.
Living on the mooring with NO shore power cord and no real need to run the generator for battery charging, solar is all I need to keep my batteries charged. But based on my Amp meter (which lies more than a politician) my typical SOC during the day is 50% to 80ish %. When I want to impress myself with these batteries I will run my 1500W hot water heater for 30 minutes just to drag the SOC down a bit for fun. Typically my batteries are at 13.8v for...maybe 4-5hrs per day, load and sun dependent.

After the last year on LiFePO4 batteries....I would NEVER go back.
It's easier than the experts want to make it and even better than they hype it!

Thanks.

If that works in the long term it would be a lot simpler than the "no float voltage" rule that some are suggesting.

Cheers,
JM.

[SV THIRD DAY]

Originally Posted by NahanniV

Thanks.

If that works in the long term it would be a lot simpler than the "no float voltage" rule that some are suggesting.

Cheers,
JM.

It boils down to the concept that "float" is typically associated with batteries being at a full SOC, but I'm intentionally setting my "float" voltage below the full SOC, so that the battery simply can't get fully charged at that voltage, so it eliminates the worry/fear of over charging. So much about these batteries go against everything we were taught about lead acid that is really takes some time and you actually have to force yourself to get out if the lead acid thinking and box. To not fully charged your lead acid and "float" them below a full SOC would be lead suicide, but for these batteries...well sonfar they don't care!

[Maine Sail]

Originally Posted by SV THIRD DAY

It boils down to the concept that "float" is typically associated with batteries being at a full SOC, but I'm intentionally setting my "float" voltage below the full SOC, so that the battery simply can't get fully charged at that voltage, so it eliminates the worry/fear of over charging. So much about these batteries go against everything we were taught about lead acid that is really takes some time and you actually have to force yourself to get out if the lead acid thinking and box. To not fully charged your lead acid and "float" them below a full SOC would be lead suicide, but for these batteries...well sonfar they don't care!

I thought you were charging at 13.6V or 3.4VPC. Did you up that to 13.8V..?

[exMaggieDrum]

Great discussion here. Thanks to all. The last few posts have definitely helped zero in to the day to day nuts and bolts of battery management in different usages.

[SV THIRD DAY]

Originally Posted by Maine Sail

I thought you were charging at 13.6V or 3.4VPC. Did you up that to 13.8V..?

When I first installed the batteries I did set all the voltages on my various chargers (bulk/absorb/float) to 13.6v (13.4v at first actually at Mark Grasser's recommendation). But after getting comfortable with the system and that it was all working well, I upped the voltage to 13.8v. So far so good. No over charging, no cell drift noted, and no drama.

[senormechanico]

Rich,
Those are my numbers too.
No drama with lots of juice to work with (One 200aH bank for the whole boat).