Will put my 2 cents in here,
Batts no matter what type are just a storage device.
For example your car, rated at 12 volts, batt is 12 volts, the charging current going into the batt is 13.5 to 14 volts.
Depending on the state of discharge and governed by the voltage regulator.
You would never get a fully charged batt with just a 12 volt charge going into it, has to be higher.
12 volts is already considered 50 percent discharge.
On the 747 batt voltage is 32-36 represents a normal batt charge.
The apu batt is only used during apu start, but has a lower voltage requirement on pre flight.
The main ships batt is always lower because it is wired to the hot battery bus and always has a discharge , clocks etc.
Just wondering if this main ships batt is very low and not being charged as much due to short flights, maybe overheatingtrying to make up for the loss, a sponge even though dry can only soak up so much water a a time will will try to take as much as it can.
If you overcharge or exceed it it will boil over.
Sorry just and old F/E and thoughts.
Thats why the smoke and mirrors replaced us,
They know best.
Last edited by Earl; 21st Jan 2013 at 06:18.