How to set charge parameters on Midnite solar classic charge controller to charge LiFePO4 batteries

Cuteajax

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Joined
Apr 17, 2021
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14
I just procured two pieces of 24volts 200Amphr LiFePO4 batteries for my 24 volts solar system that includes a Midnite solar classic 200 charge controller and an Outback VFX3024E inverter. I will be connecting the two batteries in parallel for a resultant nominal voltage of 24 volts. I understand that the "float" aspect of the charging algorithm is not necessary for LiFePO4 batteries. How do I set the charging parameters on the Midnite classic charge controller?
 

Cak

New Member
Joined
Jul 5, 2021
Messages
1
My understanding of LiFePO4 cells is that they do still need the float stage. They want a constant current and then a constant voltage charge. So with older chargers designed for lead acid the bulk charge provides that constant current and the float provides the constant voltage. However for lead acid most chargers also have an absorb charge phase that is not wanted for ion types because it can overcharge/overvolt the cells. I don't have that specific charge controller but on my Outback charge controller I was able to set the absorb time to 0. So with my off grid home I was able to change the bulk and float cutoff voltages to the appropriate ones for in my case Lithium ion and everything seams to be working well.
 
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