Diego
Topic Author
Posts: 135
Joined: Mon Apr 23, 2001 7:33 pm

Battery Vs Alternator

Sat Aug 04, 2001 3:34 am

hi folks here I got another question that bugs me:
given for granted that the alternator feeds the electrical system and recharges the storage battery after start up once the engine is cranked, what is the purpose of recharging constantly the battery once it has been completely recharged and does the battery looses its charging by feeding somehow the electrical system during normal alternator operations?
Thanks REGARDS DIEGO
 
cdfmxtech
Posts: 1319
Joined: Wed Jul 05, 2000 11:37 am

RE: Battery Vs Alternator

Sat Aug 04, 2001 7:34 am

OK..first for this conversation - let's call the alternator an AC generator/IDG. The battery charger is charged using AC power, so External Power or any AC generated power source can power the charger.
The charger can completely charge a dead battery, so lets say, we walk on an aircraft with a dead battery. It takes this aircraft an hour to completely recharge the battery. The charger will charge this battery at a certain rate. When its senses that this battery is fully charged, it will reduce the rate of its pulse to maintain 100 percent charge. It will not overheat the battery.

I think I spit out alot right there. I hope you can understand

Cdf
 
Guest

RE: Battery Vs Alternator

Sat Aug 04, 2001 8:37 am

try typing this in "search" this has been talked about before.
 
dc10hound
Posts: 460
Joined: Fri Dec 15, 2000 4:18 pm

RE: Battery Vs Alternator

Sun Aug 05, 2001 3:38 am

>>The charger can completely charge a dead battery, so lets say, we walk on an aircraft with a dead battery. It takes this aircraft an hour to completely recharge the battery<<

On the A300, once the batteries are dead, it's over. The batteries must go to the shop for maintenance.
I believe it's the same on a DC-10, also.




"Eagles soar. But weasels never get sucked into jet intakes.."
 
Klaus
Posts: 20622
Joined: Wed Jul 11, 2001 7:41 am

RE: Battery Vs Alternator

Sun Aug 05, 2001 6:46 am

Dc10hound: On the A300, once the batteries are dead, it's over. The batteries must go to the shop for maintenance.

Are you sure? Why is that? (Curious)
 
ukair
Posts: 261
Joined: Tue Mar 27, 2001 11:36 am

RE: Battery Vs Alternator

Tue Aug 07, 2001 8:49 am

Aircraft rely completely on their batteries for dc current so as the power in the battery is used up it is replaced by power from the ac generator get it?
 
Klaus
Posts: 20622
Joined: Wed Jul 11, 2001 7:41 am

A300 Dead Battery

Tue Aug 07, 2001 9:04 am

Ukair: Aircraft rely completely on their batteries for dc current so as the power in the battery is used up it is replaced by power from the ac generator get it?

That´s what I was thinking and that´s why DC10hound´s remark baffled me. Shouldn´t it be possible to just recharge the dead battery in-site?

Unless by "dead" DC10hound meant DEAD, of course...  Wink/being sarcastic
 
chdmcmanus
Posts: 372
Joined: Wed Mar 21, 2001 12:53 am

RE: Battery Vs Alternator

Tue Aug 07, 2001 12:47 pm

AC power is rectified into DC power through a Transformer-rectifier before charging the battery. There are two methods of recharging Lead acid and NiCad Batteries, constant voltage and constant current. Constant Voltage Re-charging is most commonly used in acft. When a Lead-acid battery is completely discharged, excess sulphation and plate shedding occurs which can lead to over charging and excessive heat. In NiCad batteries, full discharge may cause individual cells to reverse polarity and create an internal short. Most acft have a battery or charging relay in the DC elec system with a pre-determined minimum voltage to prevent the battery from being re-charged once the voltage falls too low.

Regards,
Chd
"Never trust a clean Crew Chief"
 
Klaus
Posts: 20622
Joined: Wed Jul 11, 2001 7:41 am

RE: Battery Vs Alternator

Tue Aug 07, 2001 9:09 pm

Ah, ok. So it was about deep-discharged batteries... Then it´s clear.

Thanks!

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