Flat Battery ..... Consequenses ?
 

Scenario: Regional turbo-prop operation. Whoever left the aircraft last the night before left the battery switch ON. When the morning crew arrived .... Flat batteries !
Question. What happens to the battery in such circumstances. What are the consequenses of a battery flattened this way. Normaly the batteries are removed to be serviced in the maintenance shop ... but what is actually required to be done ? Do they just connect it to the charger and that's that or is there more to it ?
Question. If no maintenance facilities are available, can external power (GPU) be connected to the aircraft and let that recharge the battery in-situ ? If so are the batteries OK to continue or are they compromised in some way ?
Would appreciate some 'good info' on this. Can anyone help ?

You may be better off with this in the Engineers and Technicians' forum.

In the type I used to fly if the battery was flattened this way it would go off line. There wouldn't be enough power left in it to energise the relays so even if you plugged in a ground power unit you couldn't connect it! The batteries would always be replaced in this scenario. Don't know what happened to them after that.

Had this on a B767, left the battery turned on all night, put the GPU on for half a hour and it charged up to 28volts. This was with Ni Cd battery would not be good to do on an old lead acid battery.

One need to fully recharge the battery, that is about 12 hrs at a low Amps rate, so better to change the battery for a loaded one...and use your checklist!

From my time on the A320:

BATTERIES ............................ 25.5V/AUTO
If the aircraft has not been supplied with electrical power for 6 hours or more, perform the following check:
- BATT 1 and 2 ......................CHECK OFF
- BATT 1 and 2 VOLTAGE ........CHECK BOVE 25.5V
(Battery voltage above 25.5V ensures a charge above 50%
. If battery voltage is below 25.5V a charging cycle of 20 minutes is required
- BATT 1 and 2 ...................... AUTO
- EXT POWER ..........................ON

This would imply that battery removal is not required (on the A320 family) and that after a 20 minute charge cycle all is legal to dispatch, and that should you suffer a complete electrical failure the batteries will have the required level of charge to see you ok for 30 minutes.

That's my interpretation. Now back on Boeings and nothing so explicit in our manuals.

The only problem is that ground power chargers are very slow and inefficient and should not relied upon to recharge fully flat batteries they are only any good for trickle charge batteries in good charge condition(only talking about B747s)

Would that be ATR machine?

Are we discussing Lead Acid or Nicad batteries?

And are there any aircraft using Lithium Iron batteries yet?

Most (if not all) aircraft electrical systems do not regulate the charge rate for the battery. When a battery is electrically discharged (flat) it will draw a very high current if charged from the aircraft. This can result in the battery overheating, damaging the plates (lead acid) and cells. Not good and can be a potential fire hazard.

TH

You need to be careful with batteries and look after them.

If you have the faciality to do a battery engine start on your A/C, eg., a light jet or TP, and you have the choice of a ground power, take the ground power every time.

This will avoid putting unecessary loads on you battery. You will need every volt/amp from your battery in the event of eg., all generators off line, for what ever reason, in IMC at night for instance.

You will have about 20-30 mins to get the A/C on the ground if the battery is in good condition, to run the standby equipment.

The above may sound like basics but you will be surprised the amount of pilots (and engineers) who don't keep this in mind.

To answer your question, get the battery changed for a fully charged battery if possible.

747 have their own battery chargers installed and that has nothing to do with ground power. The batt chargers do pulse charges over a set period of time/cycles.

Flight Detent; Close but it was ATP!

Completely dead battery?
Certainly a bad news day, for sure, with many aircraft.

Turbine powered:
Many have nickel-cadmium batteries, and these would absolutely need to be removed for proper deep cycling.

If by chance your turbine aircraft has a lead-acid type, this also would need to be removed, and properly charged to full capacity.
Less critical than the ni-cad type.

Piston powered.

Most of these have lead-acid ships batteries, and altho it might in this case be able to connect ground power to start, it would be exceedingly unwise.
Many piston types have limited ability to regulate the charging amperage, and battery overheating (possible boil-over) is a distinct possibility.

IF you have ever had a problem with overheating/thermal runaway with a ni-cad battery, you would surely wish you had called in sick for the flight.

Absolute nasty business, bar none.:uhoh: :uhoh: :uhoh:

On a general battery point, lead acid batteries do not "like" to be fully discharged, their prefered life is being topped up regularly. NiCad batteries on the other hand like being "cycled" through fully charged to fully dischrged, in fact as any model owner will tell you, you can "rejuvinate" NiCads by charging them fully and discharging fully a number of times and each cycle will increase the power held in the battery.

Lithium Ion (not Iron;) ) are much less fussy as are NiMH, but they are pricey. easily 4 times the pice of NiCad