Solar MPPT and lithium batteries

alpen1 wrote:
I switched my AGM batteries to lithium's. I can't get a definitive answer on MPPT charge parameters, except to "user define" which I have done. My question is: since MPPT chargers rely on voltage drop to start the charging process, and lithium batteries maintain a consistent voltage until depleted, how will the controller know when to charge?
The "user defined" parameter settings seem like a work around, but spending a week and watching the voltage stay the same, but capacity drop with minimal amperage charging from the solar panels, I wonder how long before they are depleted? Is there a solar charger that uses capacity drop to start the charging process?

Might help to post the controller make and model.

Also post your user defined settings.

My Morningstar MPPT 60 wakes up with the sun every day and puts 13.8 volts into the battery and then drops to float at 13.0 volts. Yes the battery will rest at about 13.4 13.3 all day never getting power from float. Next day controller pushes the battery back up to 13.8 volts. No issues.