G3X IBBS Pin 5 info

Hey All,

I would like notification on the GDU if I lose power to my IBBS pin 2 (trickle charge).i have a couple of ideas, but before I entertain them need to know if that is already handled by connecting pin 5 (info) from the IBBS to the GEA24.

Can anyone enlighten me?

CJ

Captain_John said:

Hey All,

I would like notification on the GDU if I lose power to my IBBS pin 2 (trickle charge).i have a couple of ideas, but before I entertain them need to know if that is already handled by connecting pin 5 (info) from the IBBS to the GEA24.

Can anyone enlighten me?

CJ

Click to expand...

Hello CJ,

As shown in the G3X Installation Manual, pin 5 (info) on the IBBS is normally connected to one of input discretes on the GEA 24 or GSU 73.

An Active Low alert can be configured to provide the pilot with an indication that the backup battery has gone into use during flight.

The trickle charge input (pin 2) is normally connected to the positive terminal of the main aircraft battery to keep the IBBS backup battery charged (4 mA max) when the aircraft is not in use.

There is no way to be notified when the pin 2 trickle charge input is not being powered, but this is only used when on the ground when the aircraft is not being used, so there doesn't seem to be much value to GDU notification of when the trickle charge line is not powered, but let us know if we are missing something here.

Thanks,
Steve

Yes,

The status of pin 2 is of concern to me because if it was inop, the aircraft was out of use for an extended period and I was unaware of this situation my typical startup routine would be affected.

What i was thinking was to use the positive lead of pin 2 to maintain an open on discrete number two. If the power was lost it would pull an active lo on discrete two and notify me of the scenario.

I was thinking of installing a push to test LED, but with all the technology I have available to me, this would be a step in the wrong direction.

Creating a switching device to do this is difficult, as it could be a current drain while the aircraft is out of use.

Soooooo... I know this isn't needed, but if it could be done easily it would be nice to have.

What is your take?

Thanks in advance!

CJ

Steve,

Thanks!

Yes, but getting a positive wire to pull an active lo is quite a trick!

Any ideas?

Anyone?

CJ

CJ,

You could put a Schottky diode inline along with a pull down resistor on the anode side of the diode.

Not sure how well the IBBS will handle the voltage drop across the diode on its charge line.

If the charge voltage goes away, the pull down will pull the anode side down and leave it at a lower potential than the cathode side. That would trigger the G3X's active low input.

Bri,

Not a fan of the (very slight) current drain.

What else ya got?

I would trade two active lows for one inactive hot!

hahaha

CJ

What drain you referring to?

EDIT:

I see now that the IBBS (can you tell I am no IBBS user?) has pin 2 (trickle charge @ <= 4mA) connected full time to the main battery positive.

In that case, a pull down resistor I suggested would always be sucking current off the main battery...not good over time!

Looks like Ian has a suggestion for you below....

or thinking outside the box here:

How about you tie the low side of the pull down resistor to the master contactor switch which is only low when the master is on. That way your pull down resistor only draws current when the master is on?

Captain_John said:

I would trade two active lows for one inactive hot!

Click to expand...

I believe you are looking for a FET (Field Effect Transistor). Voltage controls current, with no leakage (well, very, very little).

--Ian Jordan
Dynon Avionics

Hmmm,

Ian, I like the sounds of this!

Could you give me some details on your thoughts?

Components, diagrams, etc...

I will run it past my "consultant"!

CJ

Pin 2 and the IBBS

I would recommend not adding any other components to Pin 2, particularly an added series diodes as this reduces the input voltage presented on Pin 2. Since the function of pin 2 is to provide a trickle charge feature to the back-up battery so as to ensure that the battery can accept a full charge from the fast charge circuit which is enabled when main aircraft power is applied to pin 1 when the aircraft is operational, it's condition is best indicated by the behavior reported on Pin 5, "the info pin". When the aircraft is operating normally, pin 5 will report the internal battery voltage, when main aircraft power is lost, pin 5 is driven low to provide a warning signal. Therefore, the condition of the battery is shown by pin 5 during normal operation and really tells the story if there is an issue with the charging system. Under normal operating conditions you will see an internal battery voltage of about 12-15 volts, if you every see the battery voltage stuck around 10 volts or less, then the integrity of the pin 2 connection or capability of the battery (end of life) needs to be investigated.


Bob Newman
TCW Technologies, LLC.
RV-10 N541RV

Although this seemed like a good idea at the time, I am abandoning this thought.

Last night I wired the pins in the published fashion.

Thanks all for the ideas!

Perhaps an alarm like this could be integrated into future releases? I bet that there are other uses for a function like this.

CJ