I have an old 30' sailboat with a primary lead acid battery bank and a 55 amp alternator. This primary bank is used to start the engine and as house batteries. They are deep cycle lead acid batteries. I recently installed a lithium bank with a Orion TR Smart Isolated 12V 30 Amp DCDC charger. The lithium bank is primarily used to power a portable refrigerator. I also installed a BMV 712 Smart battery meter.
I notice during bulk charge while the engine is running there are 25-29 Amps being provided by the charger and the input voltage for the lead acid bank/Alternator drops (as expected).
However, sometimes. the input drops as low as 9 volts (Input voltage for the DC DC Charger from the lead acid bank/Alternator).
Is this normal or am I degrading the lead acid batteries somehow? or is there an alternator issue? should I consider switching to AGMs or upgrading the alternator?
Thanks in advance!