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aircraft battery


mrjpc130h
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hi guys...

does anyone knows how long the batry will provide power in case of emergncy n totally electrical failure in flight? is it true it is not adviseable continuos charging batery on ground and y?

another one is how to differntiate system tht use solid state n non solid state aicraft system..

if too much pls provide references so i cn check it

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hi guys...

does anyone knows how long the batry will provide power in case of emergncy n totally electrical failure in flight? is it true it is not adviseable continuos charging batery on ground and y?

another one is how to differntiate system tht use solid state n non solid state aicraft system..

if too much pls provide references so i cn check it

RZ hit in..... How long? Depends on your load.... If you have a total electrical failure and you have BOTH (AC INST and CP's) of your inverters ON you will drain the Batt rather fast. If you run only the CP inverter (for flight insturments) your Batt will last much longer.... so NO "real" answer to your question.

The Batt can overheat if overcharged... I've never had a problem; it was an issue in the past with the OLD Batt.

Not sure what you are asking about when you say "solid state or Non" Are you asking about the inverters?

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Years ago, up in Kodiak, we tested a battery in the hangar. It was about 54 degrees F. The battery was a NiCad, due for removal/overhaul. Turned on everything it would power in flight. It ran for several hours before the voltage dropped to below 23 volts. Now if you were at altitude for a while, that battery will be much colder. I wonder if this was ever tested at some of the cold weather test facilities in the past with NiCad or lead Acid batteries?

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Years ago, up in Kodiak, we tested a battery in the hangar. It was about 54 degrees F. The battery was a NiCad, due for removal/overhaul. Turned on everything it would power in flight. It ran for several hours before the voltage dropped to below 23 volts. Now if you were at altitude for a while, that battery will be much colder. I wonder if this was ever tested at some of the cold weather test facilities in the past with NiCad or lead Acid batteries?

I wonder how cold the battery would be at altitude. Since the aircraft is continually overcharging the battery, 25-30 volts into a 24 volt battery, it creates heat and helps prevent the battery from freezing, or so I have been told.

Mike

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Based on C-130H 24volts lead acid battery rated at 36 amp/hr.

We have been learned that during flight if all AC generators lost and the battery is the only source of power aircraft will be left with two electrical buses only (BAT BUS & ISOLATED BUS) in which the battery bus will provide us with the ability to extinguish any fire on the engines and the ISOLATED BUS will provide us mainly with the following:

1- 3 crew interphone (P, FE, LM)

2- Radio com. (VHF1 & UHF1)

2- The ability to operate one inverter only (co-pilot inv.) flight directors No1 & No2 (ADI)

The time required for the Battery to reach the discharged state depends mainly on the use of the above, so theoretically if the total draw is 36 amps. The battery will be discharged within one hour, and with 72 amps the battery will be discharged within approximately halve an hour.

In such situation reducing the load to the minimum is essential to maximize the time by switching off/pulling CB any unnecessary items (Co-pilot inv.) if not required at the time.

The estimated time to use the battery in this situation without reducing the load is 15 to 20 minutes.

Point to be known that when battery voltage drops to (15 to 18 volt) the isolated bus will be lost (battery relay will deenergized); air craft will be left with 15 volt battery bus.

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tenten,

your right...I mixed the conversation (ground operation of both inverters). The only inverter that will have power is the CP inverter as you stated and the discharge rate will depend on load. If the aircraft is older and has the DC driven motor that turns an AC gen the amperage load will be higher than a newer aircraft with a "solid state" eletronic inverter(no moving parts to "drive"). Also as you point out the Batt relay will not remain energized when the voltage drops to "the voltage at which there is not enought power to hold the relay".... Just hope you are VFR at that point as you will have 9 minutues to "find" VFR (stby gyro).

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