LiFePo charging voltage
 

I just installed a Shorai LFX18L1-BS12 battery to replace a dying PC680. The installation was easy enough, there were plenty of shims with the battery. The battery is coming up at 13.4V. I gave the plane a quick start, starting was definitely better. I got a voltage drop to about 9V while cranking (the PC680 was closing in on 6V). Once started, I switched on my alternator and was a little surprised to only see a slight voltage bump to 13.8V. This is 0.4V lower than the PC680 during charge. I cycled the alternator field and saw immediate drop and return to the same 13.8V.

My question is, should I be concerned about the lower charging voltage?

My EarthX shows about 14.3v when charging ......

It should charge just fine at 13.8 - perfect. The LiFePO batteries really don't like high charging voltage and will charge and deliver the power just fine where you are. I would be happy. It will draw a much higher current than a PbA battery if below full SOC.

I agree the lower voltage is better for the LiFePO batteries
 

I also have the Shorai battery now for a little over 5 years. I adjusted my alternator voltage down to 13.8 volts to extend the life of the battery.