for Boeing and Airbus battery...24 volts is the standard but it reaches up to 28 volts [full charge]if i'm not mistaken 22 volts is the minimum to start a APU...

for Boeing and Airbus battery...24 volts is the standard but it reaches up to 28 volts [full charge]if i'm not mistaken 22 volts is the minimum to start a APU...

Close John!Jack C

Where would I be supposed to find these things anyways, apart from Google...?

The POH has these answers.

But, if my battery doesn't have enough volts to start, can I call AAA?

12-14v depending on temperature.....final answer

John's still the closest and so very close!Jack C

21v............now im just guessing.................i searched for this information for 2 hours. and all I've gotten was the voltage range (22-30v) and if the apu does not start due to low voltage (didnt say what low voltage is), use ground power. Ive looked EVERYWHERE (and if you know better PLEASE let me know) but anything short of buying a Boeing 737 and reading the manual, i just don't know. I know Boeing doesn't sell their manual to just anyone, and im not about to go to a torrent site and steal it......but yea this is fun......so cant wait for ?#4..

Have you looked at http://www.smartcockpit.com/. It's a good place to look for info.My guess is 23 volts, that's the info I could scrounge up for the 737 classic. Not sure about the NG.@M. CarterThe check for TR serviceability is current, not voltage, because the TR voltage indicates that of the associated DC busses (for TR's 1 & 2). TR's should always be checked before commencing an autoland because the TR3 disconnect relay / cross bus tie relay opens at glideslope capture and this will leave DC Bus 1 unpowered if TR1 had previously failed. NG's have a TR UNIT light which illuminates if either TR1 or TR2 and TR3 fail in flight or if any TR's fail on the ground. The TR's are unregulated and output rated to 50 Amps.

Have you looked at http://www.smartcockpit.com/. It's a good place to look for info.

Accually I have.........it is a GREAT website......but still no information on the min start voltage......I even took some APU quizzes on that site to see if it would ask this question.......it did not.

I suppose that is a bit of a tough one. Its 23v. I tried to look for it on mycockpit too but couldn't find it. To be fair it is on our preliminary checklist. I will take a look and see if I could find it in a manual. Here is a bit of an easier one.#3 What are the altitude restrictions for the following loads on the APU1) Bleed air + Electrical2) Bleed air3) Electrical4) Max altitude for APU startJack C

I suppose that is a bit of a tough one. Its 23v. I tried to look for it on mycockpit too but couldn't find it. To be fair it is on our preliminary checklist. I will take a look and see if I could find it in a manual. Here is a bit of an easier one.#3 What are the altitude restrictions for the following loads on the APU1) Bleed air + Electrical2) Bleed air3) Electrical4) Max altitude for APU startJack C

1. 10,000 ft
2. 17,000 ft
3. 37, 000 ft (classic) - 41,000 ft (NG)
4. 25,000 ft (classic) - max. altitude (NG)

I suppose that is a bit of a tough one. Its 23v. I tried to look for it on mycockpit too but couldn't find it. To be fair it is on our preliminary checklist. I will take a look and see if I could find it in a manual. Here is a bit of an easier one.#3 What are the altitude restrictions for the following loads on the APU1) Bleed air + Electrical2) Bleed air3) Electrical4) Max altitude for APU startJack C

1) FL1002)FL1703)FL370, 737-1/500...........FL410 737-NG4)FL250, 737-1/500 (classics)................ No limit 737-NG

Well heck that was quick Alex. And right too.#4 What is the minimum recommended cool down time of the engines before shutting them down?Jack C

I'll say three minutes!