My AGM starter battery is connected to the blue smart IP 22 charger in the normal setting. My 600ah lithium battery bank is charged by a dc to dc charger connected to the AGM starter battery. All are connected with 6guage high quality copper cables. With the shore power charger on, and the dc to dc charger charging the lithium bank, my starter battery voltage slowly drops then the dc to dc charger starts cycling on and off. My voltage cutoff is set to 12.2V and reset at 12.7. I’ve tried various settings but AGM battery voltage eventually drops to cutoff voltage. Could the AGM battery itself be the issue? I can’t figure out why it’s losing voltage while connected to the blue smart IP22 shore power charger.
