My RV has a Magnum MM1212 inverter/charger with MM-RC remote. Magnum says it does not have a specific LiFePO4 profile. The current charge profile is set for AGM2 (because that is the profile loaded in the remote and is non changeable) that has Bulk @14.5v and Float at 13.5v. What issues would I look for if I tried to use it?
This inverter/charger is 1200watts, 70amp charger, and includes a transfer switch as an all in one unit. I hate to spend another $1300 just to solve a charging problem.
I am in the same situation. In November 2021, I installed a 100Ah kit from batteryhookup.
My trailer has an MMS 1012, 1000W/50A with the same 14.5/13.5 Volt charger settings. Solar has always the primary charging source and the MMS was mainly a Bulk charge source.
I also have the remote with 6 LEDs and therefore I can observe Bulk/Abs/Float status. I have used the MMS since 2014 to charge AGMs. The Abs time is calculated during Bulk and not fixed to 120min. I have seen it start in Bulk and be into Float in under 30 minutes. That is because a lead battery is not missing many Ahs when near 12.9V. The Float stage has a 4 hour timer after which the it ceases any charge and enters standby watching for the 12.9V.
I see two LFP issues:
1. The 12.9V is nearly fully charged for lead, but ~80% DOD for LFP. This may cause an excessive charge time at 14.5V. It might be okay to reach 14.5 during Bulk, but the Abs should be cancelled by going straight to Float.
2. The 4 hour Float timer activates #1, the 12.9V issue.
Do not leave the MMS unattended when connected to an AC source. So, it is genny style charging.
The good is that the 13.5V Float charge is right at ~99% SOC for LFP.
How to trick the MMS into using 13.5V Float? By taking a Voltage reading you will know where you stand on the 12.9V issue.
If under 12.9V you do Constant Current(CC) until 13.2V(3.3V/cell), or ~70% SOC. Then, stop and start the MMS and it will do Constant Voltage(CV) until 13.5V(3.375), or ~99% SOC. You can stop/restart this CV if you need the MMS to serve as a power supply. Otherwise, you are done and can shut the genny off.
With solar available, you can use less genny time if you use the genny early in the day.
P.S. Actually you can be done charging e.g. after CC if you only need 70% SOC looking ahead. LFP does not often NEED to be fully charged.