I understand there are some current electrical difficulties with the -800 VC model, but I'm not sure if this is related.Please take a look at the following shot. I took this in the -800VC in a cold & dark scenario. The only thing I have done is switch battery ON and DC Meter to BAT.The voltage looks good, but shouldn't the DC ammeter read 0?Also, why is there any AC Power displayed at this point because ground power is off and APU is off?Any comments?Thanks!Jeffhttp://forums.avsim.net/user_files/74269.jpg

"The voltage looks good, but shouldn't the DC ammeter read 0?'According to PMDG, all the indications/values on the panel are not modelled correctly, but there definitely should be current draw, as the battery is feeding the Standby Power system (Your Standby Power switch is in AUTO, so the Standby Power system will cut in automatically with the loss of power on the main busses)."Also, why is there any AC Power displayed at this point because ground power is off and APU is off?"The Standby Power System provides AC. However, due to my limited experience with the NG, I cannot tell you if the displayed values are correct.Hope this helps?Cheers.Ian.P.S. Our airline has just begun running 737-800's from the area where I work (on a regular basis)... so, hopefully, I may be able to tell you if the values displayed are correct (They may, of course, vary from aircraft to aircraft).

"(Your Standby Power switch is in AUTO, so the Standby Power system will cut in automatically with the loss of power on the main busses)."Sorry, no, the Standby system will not be powered automatically when on the ground!! You must move the SBY SWR switch to BATT when on the ground to power the SBY bus!"The Standby Power System provides AC" I think the SBY system only provides AC via a standby inverter and not via conventional AC.Hope that helpsKris

In real life, larger turboprobs and jets have something calledinverters.Inverters convert DC power to AC and transforms the voltage,but im not shure if PMDG have modelled this accurately ormade this in the 737NG at all!just like Kris wrote it's inverters making the AC power.Batteries in airplanes are ment for emergency situations,and therefore never used alone to power the aircraft on ground!!If both engines fail in the air Pilots will have to pull outa fuse calles NON-ESSENTIAL AC or something like that..or else the battery will be flat in matter of minutes!!

Understood re: the inverters. The reason I brought this up was more to determine if the -7 reading on the ammeter is correct (thought it should read 0). I just, as a side note, had a questioned the AC readings.Thanks!Edit: So, after re-reading this, I want to make sure that I understand. The AC readings in this picture are not correct because, in order to generate AC from the batteries, the Standby power switch must be switched to battery?Am I correct?

The stand by setting only takes power from the bestsource available, which in this case means that the batteryis the only source!the auto and battery setting on the standby source switch guard,is taking power from the best source, unless you putit on battery when APU or EXT. power is accessable.then it will drain the battery.So as long as the Battery is the only source it will only take power from the battery, nomatter ifyou have the DC selector on BAT or Standby.but remember: an aircraft on this size has gotmore than one battery! so standby and BAT. settingon the selector is the choice between the batteries onboardCheers :)

"In real life, larger turboprobs and jets have something calledinverters.Inverters convert DC power to AC and transforms the voltage,but im not shure if PMDG have modelled this accurately ormade this in the 737NG at all!"The B737 uses things in reverse to the older turboprops! ALl power supplied by the engines is AC! The system uses Transformer Rectifier Units to change the AC 115V to 28V DC. There are 3 TRU's that supply the DC system. Should it all go horribly wrong and you loose both generators (and the APU) in the air the system with automatically flip to the standby system and crank up the emergency inverter, in this situation the Battery will be supplying the DC system and the essential AC via the inverter. The standby system is linked to the weight switches which prevent use of the standby power system inadvertantly on the ground. In order to get standby power while on the ground you must select the guarded STANDBY POWER switch to BATT! In other words in the air the system automatically switches to standby but as soon as you land the system trips off and must be manually set to BATT. From what I understand the figures on the ammeter / voltmeter display is garbage as MSFS is not very good at it so PMDG did their best but ultimately they can't simuulate everything! As a point of note the F27 I used to fly had 2 (3 on some) inverters which remained on even in an emergency. There is a special loadshedding circuit which in theory ensures the battery will only supply essential equipment and will last for up to 30 minutes. The 30 minute rule is pretty much current on all types, most battereis will give you essential services for 30 mins, beyond that you are tempting fate... just remember ZERO VOLTS = ZERO FEET!! ie if you're on battery get down sharpish!Hope that clears matters upKris

Hi Jeff,The -7 shows that the battery is being discharged to power the 28-volt DC standby bus and the 115-volt AC standby bus which is poweredby the battery bus through the static inverter.On the NG's the Standby Bus is armed in Auto while on the ground and this is why you see the AC Volts and Freqs in the Stdby selection. The earlier comment that the Auto is disarmed on the ground is only applicable to all 737's prior to the -600.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.precisionmanuals.com/images/forum/ng_driver.jpg

>The stand by setting only takes power from the best>source available, which in this case means that the battery>is the only source!Correct! >>the auto and battery setting on the standby source switch>guard,>is taking power from the best source, unless you put>it on battery when APU or EXT. power is accessable.>then it will drain the battery.>Also Correct>So as long as the Battery is the only source it >will only take power from the battery, nomatter if>you have the DC selector on BAT or Standby.>>but remember: an aircraft on this size has got>more than one battery! so standby and BAT. setting>on the selector is the choice between the batteries >onboardThere is no way to select individual batteries, yes there are several cells but they are not individually selectable and should be considered as one. There is not a STANDBY position on the STANDBY POWER switch, there is AUTO (flips automatically if all generators are lost while in the air), OFF (disables the system completely) or BATT (which manually activates the Standby power system and ties the Battery to it!) this is only ever used in an emergency when on the ground (say during a pax evac) or when landing following a double gen failure, this stops the standby system turning off when you land and put weight on the squat switches.Hope that clears the matter up!Kris

John I stand corrected on the AUTO Setting on the ground. it is logical that Mr. Boeing would have removed that foible when they produced the NG! All my info is the 3/4/500 series!Kris

YES, but when you do NOT have engines running theinverters will transform DC to AC!!and YES it is most likely garbage displayed in flightsim!!and i did not mean that you could select between cells as you wanted too, i ment that there is NOT only ONE batteryonboard the 737...

YES, i ment AUTO on the switch guard not standby!

>YES, but when you do NOT have engines running the>inverters will transform DC to AC!!Agreed>>and YES it is most likely garbage displayed in flightsim!!>>and i did not mean that you could select between cells >as you wanted too, i ment that there is NOT only ONE battery>onboard the 737...NorwegianI didn't want to spark an argument it's just that the info you put across is not how it works. I realise that there is a language difference, I posted in order to prevent confusion for other readersRegardsKris

Hi,Just a reminder to post your real name as per the forum rules :D Please excuse me if your name really is norwegian.no :)Anyway, to hopefully clear this up, the original poster asked if what he was seeing was right and the short answer is YES!As for the battery, the 737 only has a single 28 volt-dc nickel-cadmium battery.Cheers,JohnBoeing 727/737 & Lockheed C-130/L-100 Mechanichttp://www.precisionmanuals.com/images/forum/ng_driver.jpg

Ahh, I bottom-line kinda guy!Thanks for the answers!