From the Heart Interface manual for the Freedom models 10, 15, 20, 25
Steady Overload LED - Indicates an over-temperature condition, the unit is shut down.
It will reset automatically after cooling.
Blinking Overload LED - Inverter mode- Shutdown, diagnose problem using DC Amps
bargraph. Charger mode- Excessive DC voltage ripple.
Remove loads from DC battery bank. See LED 5 in the
Troubleshooting Chart, page 34.
From page 35, LED 5 - Battery overload caused by excessively discharged
batteries. Refer to page 15
From page 15:
Charging Over-Discharged Batteries -
Charging a battery bank with a terminal
voltage of less than 8 Volts presents a special
problem for the unit. If this situation arises, the
unit will attempt to charge for 1 minute. If the
charger senses excessive ripple voltage, it will
shut down to protect itself.
To successfully charge an overdischarged battery, you must remove as
much DC load as possible and set Power
Sharing to the lowest setting.
(And there is more to read on page 15).