how to avoid loosing power

[Nasdik]

tried to get answer from existing pool of q and a couldn't locate good one.

here is my issue I have 2 poly panels, 100 wt and 220wt 20 amp mppt charge controller, and 12 volt battery bank, mix.2-12 volt and 2-6 volt golf cart batt...panels connected to controller and than batteries to power inverter, during day time I c charge up to 14 volts but than at t end of the day it drops to 12+, how to prevent power loss,.heard about batterie isolator is that something that I need,..please advise

[daz]

... during day time I c charge up to 14 volts but than at t end of the day it drops to 12+, how to prevent power loss...

That sounds about right. Your battery should be cycling around 14.5V max, but remember 12V batteries are not 12V! They are nominal 12V. A fully recharged 12V battery will be around 12.6V, so there is no mysterious "loss" that you are seeing.

What was the actual voltage that you measured at the end of your charge cycle (before your loads started drawing power from it)?