FYI Storage and Endurance Testing of the TCW IBBS 3AH battery

[Neal]

The thought came to mind this morning, how many of us may have a degraded TCW IBBS battery and not realize it? My thought about the IBBS until recent discussions and education on this forum was "who cares" it's just a backup for the G3X and some planes don't even have it in the CubCrafters lineup I'm told such as the XCub circa 2021 when I was having IBBS issues. After learning about alternator failure procedures from @Cactus Charlie in other threads I realize that the IBBS usage can be crucial in an alternator failure scenario in preserving the starter battery for electronic ignition, etc.

I personally have never tested my TCW IBBS battery but I am aware of the voltage on startup and in flight use. The other side of this that applies to me is storage as I go on RV trips that last 3-4 months at a time typically. I initially looked at the IBBS 2AH documentation and it mentioned not to let the battery go unused (uncharged) for more than 3 months, however, the 3AH documentation states 9 months. I happen to have the ground charger purchased from TCW which I've yet to use when my last plane had the IBBS in use issue for 6 months until I found the wire disconnected from the breaker one day. It would be painful to connect the charger from having to remove the right forward panel but also getting the serial connector off the battery and installing the ground charger connector, so I hope to never have to use it, but I have it.

So the question is, is your TCW IBBS battery good? I believe the lifespan of the battery is advertised to be 6 years? There are plenty of cubs (at least) out there with IBBS batteries over 6 years old. Have you considered it's time to change yours? Or at least endurance test it?

There are a lot of "moving" parts to consider in aircraft ownership and the batteries of which the FX-3 has three need to be properly understood, maintained, tested, and/or replaced. In the Air Force I had the luxury of a crew chief and a maintenance squadron that took care of everything. In 2021 I became a first time aircraft owner which very little education or guidance on how to use and maintain my plane provided by the manufacturer. A very scary thought and this is why I've been frantically educating, learning, etc. all I can about the systems of the plane I'm responsible to maintain. Don't be complacent, learn your plane, maintain it properly.

 

[Cactus Charlie]

The TCW IBBS used in our FX-3 should be endurance tested at least once a year. I run this test during condition inspection as that's typically the only time I'm in the hangar long enough to monitor the voltage and terminate the test before the voltage drops too low.

As I have reported previously, an IBBS in good condition will power the G3X Touch system for over 2 hours. In one test with a new battery pack I saw over 3 hours.

I continue to learn more about the IBBS as I consider how to use it as an ignition backup. Today I found out that the XCub Right IGN backup uses an IBBS version with an internal heater. It may be this version but not certain -

https://www.tcwtech.com/wp-content/uploads/2020/03/725.0002-Install-Instr-3.1-IBBS-12v-3ah-CRT-V.pdf

"Pin 4 provides power to an internal battery heater system utilized when the battery temperature is below 0 C°. The nominal current draw is 1.4 amps when the battery temperature is below 0 C°."

In Arizona I'm not likely to be exposed to cold soak below freezing. How are those in northern climes protecting their IBBS from damage when charging at low temperatures?

 

[Neal]

I continue to learn more about the IBBS as I consider how to use it as an ignition backup. Today I found out that the XCub Right IGN backup uses an IBBS version with an internal heater. It may be this version but not certain -
https://www.tcwtech.com/wp-content/uploads/2020/03/725.0002-Install-Instr-3.1-IBBS-12v-3ah-CRT-V.pdf

This appears to be the certified version of the 3AH battery. I need to email them to see if the heater is only in this version, which wonderfully is nearly 4X the cost of the non-certified version.

 

[Neal]

I'm going to move some posts to a new thread, it's getting off topic...

We can discuss the temp ideas here:

FYI Thread 'Cold temps and LiFePO4 batteries in aviation'

Yesterday at 3:43 PM

The temp issue is an issue for sure with LiFePO4. I believe it's why my ETX-900 died at two years. I've had discussions with EarthX in the past about this as from what I learned of LiFePO4's is they cannot be charged below 32F (0C) or Lithium Plating can occur. It's been single digit cold in VA this past month so I know the battery has been cold soaked. While not on a charger, but once when I believe it was warm enough, once you go fly with a cold soaked battery, then what? EarthX or whomever it was recommended running the pitot heat 30 seconds prior to using the starter battery to...

• Neal
• Replies: 11
• Forum: Avionics general discussion

 

[Cactus Charlie]

According to the available documentation pin 4 is not assigned in the IBBS version we use. Since pin 4 is the heater pin it may be deduced that this IBBS has no heater.

It may not be that simple though. I have dismantled a failed IBBS battery pack. It includes a string of four 6 ohm resistors that run down the middle. The resistor string connects between battery pack common ground (big black) and a connector pin that is not present on the circuit board. The battery connector is 8 pin but the circuit board connector is 7 pin.

I had wondered if this was a built-in test load but perhaps this resistor string is the battery heater. The battery pack also contains an 8 kohm two lead device which I would guess is a thermistor. That would be required for high temperature protection but it could also be used for heater control.

So, my guess is that all battery packs have provision for heating but the circuit board on our non-certified IBBS has no provision for heater control.

It may be possible to retrofit the internal heater but that may require replacement of the circuit board and the case.

Probably a lot less expensive to pre-heat the cabin when pre-heating the engine, or to fit an external heating pad on the existing IBBS.