King Air Battery Bus
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@Stefan_K
I recommended the BS B350 to a friend which he purchased today whilst it is on sale.
However, the BATT TIE OPEN light can’t be extinguished which is out on mine.
This may have meant that his gear can be retracted but not extended unless via emergency extension system.
Is this what you had suggested, and would you have an idea why the BATT TIE caution light won’t go out?
Thanks,
Fabio -
I can't repeat the failure but some others were having what appears to be the same problem. AVSIM King Air Battery
Here's the relevant post:
I made some progress on this since I posted earlier this afternoon. From what I gathered searching online & reading the BKSQ manual, it happens when the battery becomes overcharged, and in-turn overheats. The plane will disconnect the battery bus from the electrical system to protect itself, so your only electrical power from that point onwards will come from the generators/inverters. Since the gear motor is powered by the battery, you'd have to extend the gear manually as you correctly stated.The manual does include a checklist for this event, so you can try the following:
Battery Tie Open
CTR Volts = If Matches Batt Volts...
Bus Sense - Reset
BATT TIE OPEN Annun = If still Illuminated...
Battery Bus - Emerg
Gen Ties - Man Open
GEN TIE Annunciators = Illuminated
CTR Volts = Confirm Unpowered
Number 1 Inverter - Bus Transfer
Landing Gear Relay - Pull Off
Landing Gear - Extend Manually on Approach
However, I have found the best method is to avoid it in the first place! Make sure you follow the start-up checklist by the book, no shortcuts! In particular, make sure you set the Prop Levers to 100% (definitely not feathered, which is how they will be when the sim loads in Cold & Dark), and you RESET the Gens once both engines are started, with the Gen Ties on "Normal". Once you have a good start, monitor the BAT amps on the overhead to make sure the battery stops charging BEFORE you attempt to taxi. The AMPS +/- should return to zero and the DC Volts should be around 28V. Then taxi with the engines in LOW IDLE and be very easy on the power, if the "battery charging" message comes up, stop and monitor your amps once more - if it's not too late!
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Stefan, your advice is spectacular. It hadn't even occurred to me that this might be what people are seeing. This is a great reminder of how useful the visualizations in the Duke will be to troubleshooting.
If this is the failure, then it should be preceded by excessive battery charging current and the "Battery Charge" amber annunciator. I would have to double check how I implemented this, but I don't believe the battery overheating should preclude normal operation of the other buses, though. This means that using the bus tie switch to manually connect the left and right buses to the triple-fed bus should still work. Also, if you wanted to check for this failure, you can check the state of "L:var_batteryDisconnect".
Excellent thinking Stefan, and thinks for chiming in!
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@Stefan_K
That’s all excellent and concise advice, thank-you.
On my friends BS KA B350, we follow the same procedure as on mine, with the result that the BATT TIE caution extinguishes on mine but remains lit on his.
Using the overhead rotary to check the battery, on my friends no voltage is shown whereas on mine there is (some) voltage.
There are differences in setup insofar as I have a Saitek yoke with Honeycomb Bravo TQ whereas he has a Honeycomb Alpha with BATT/ALT switches and a CH TQ.
We will later try the BATT/ALT in case there is some unseen link.
In addition, following exactly the same startup sequence, if we leave his, he battery runs down and power is lost fairly quickly.
I can’t identify where the problem is, made harder by me having to remote in to his machine which makes it considerably more tedious.
I’m feeling particularly guilty because he purchased the BS KA B350 on my recommendation albeit at the reduced sale price, so I’d very much like to fix things.
Thanks,
Fabio -
Fabio, you made an excellent recommendation. Don't doubt yourself. Its a great plane. This might be a hardware issue of key binding and not choosing the correct setting for the BATT/ALT switch. As a test, I would bypass using the Honeycomb Bravo (which I use also) and use the on-screen switches instead. Also, start from cold and dark, as you probably already are, and use the in-sim checklist. The checklist is VERY thorough. I've never experienced a BAT TIE caution using it.
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@Stefan_K
In fact, we don’t use the Honeycomb switches and use only the VC controls.
As a preference, I only use VC controls for all aircraft, I love that these have been meticulously and fastidiously recreated by way of precision virtual engineering.
However, a factor of being remote is that I don’t know how the Honeycomb BATT/ALT might work or whether it interferes with settings. Other aircraft work as expected.
We will try to Honeycomb master switches to see if that makes a difference.To BlackSquare:
Should I continue with this thread or would you prefer a new specific thread for this issue? -
Hi all, reviving this thread just to add something that I've found re: the BAT TIE OPEN/BAT CHARGE failure.
Is there any way this can be reset in flight? Or would this be something that would have to be done on the ground by an engineer?
The reason I ask - I experienced this fault on a recent VATSIM flight, the engines were running fine so I still had electrical power. However the lack of battery bus meant that my radios were bricked, and I had to disconnect because I had no way of communicating to ATC. I was using vPilot. I'm not sure if this is a deliberate functionality or not - the avionics bus was still powered, the GTN/WX radar were still operative, but I couldn't talk to ATC at all. Seems like a complex issue with a few different moving parts, but any feedback/advice is welcome on this point.
Cheers
Max -
From what you're describing, if you saw both the BAT TIE OPEN and the BAT CHARGE annunciator lights, this means that the battery disconnected from the hot battery bus due to an overheat, not a MTBF triggered failure. (I mention this only as part of my looking at the code to identify your problem.) If you didn't see those two annunciators at the same time, it's also possible that you might have hit the battery emergency disconnect switch on the left of the pilot's subpanel.
From the looks of it, vPilot must use the "CIRCUIT_GENERAL_PANEL" generic electrical circuit to identify when your radios should be working or not. I have that circuit connected to the hot battery bus to serve as the King Air's "avionics memory" circuit. Unfortunately, using only one circuit to determine if an aircraft's radios are functioning is quite limiting for more complex aircraft. I also don't blame the developers of vPilot, since that's an easily accessible variable that would usually be on the avionics bus. Knowing what I know now, I would not have set up the King Air this way, as I have learned just how many 3rd party addons rely on that variable to read the avionics power state. I will make a note of this for myself for future development.
Answering your question, I don't believe there is a way to reset that failure without reloading the aircraft, unfortunately. Again, I would have included a reset for that failure with the weather radar's "recharge battery" option if I were designing the aircraft today.
