IBBS - confessional

[jjoffe@me.com]

Discharge after fitting the new IBBS battery showed a difference of over 1.5 hours capacity compared to one that had been in service for 4 years.

I was curious so I tested the old battery pack and attempted to charge each cell with a charge controller having a proper current/voltage profile. 3 of the 4 cells charged normally but one accepted no charge. I dismantled the battery pack and inspected the bad cell. The CID (current interrupt device) on the bad cell did not appear to have tripped.

I'll be very interested to see discharge plots of other IBBS if anyone decides to run a discharge test. If you don't know how to extract and plot the data you can send me your CSV log file.

Hi - Do you know what the IBBS situation is for a Kit that I received in mid 2022 and will only start flying end of 2024 even though it is not plugged in does it degrade in the box prior to use and if so is there a way to test the battery prior to installation?
Thank you
Julian

[Andy]

Hi - Do you know what the IBBS situation is for a Kit that I received in mid 2022 and will only start flying end of 2024 even though it is not plugged in does it degrade in the box prior to use and if so is there a way to test the battery prior to installation?

Sorry, I had missed this post and only found it when I visited the thread to post new information.

TCW has provided instructions on long term storage -

"Storage beyond 9 months:If the IBBS unit is to be stored without connection to the aircraft for a period greater than 9 months, it must be connected to a source of DC power to maintain the battery’s charge. Only connections to the ground terminal and the main power terminal are required. Connect Pin 5 (main power) and Pin 9 (ground) of the IBBS to any source of regulated DC power at 12-15 volts with a current capability of > 2.5 amps to accomplish full recharging. Charger model IBBS-12v-CHARGER-Li-Fe is available from TCW Technologies, LLC. to simplify this requirement, it has the mating connector installed."

and -

"If the internal battery is fully discharged for any reason it may require up to two hours of recharge time with the normal aircraft bus on. NOTE: Do not attempt to recharge the IBBS product by using an external battery charger directly connected to the input of the IBBS. Battery chargers typically provide pulsating voltages that will damage the IBBS product if the system is not connected to a typical primary aircraft battery.
Also note, you cannot use a DMM connected to pin 5 to measure any meaningful value. Battery voltage may be read on pin 2 or any of the outputs pins 12-15 with the IBBS system enabled via the grounding of pin 1."

The IBBS capacity can be tested before installation by connecting a suitable load to the output pins, enabling the IBBS, and logging the voltage and time as the IBBS discharges. That should not be necessary if the IBBS has been charged periodically.

[Andy]

I had replaced my IBBS battery pack after the accidental deep discharge but was only seeing IBBS 12.9 V when the engine was running. This voltage is in the green range but I knew it was not normal.

I removed the IBBS from the aircraft for bench testing and found it accepted no charge current. I contacted Bob at TCW to ask for diagnostic assistance and a schematic. He declined both but did offer to diagnose the problem if I returned the IBBS to him. I expected a significant diagnostic charge and a large repair bill as the IBBS was 5 years old and well outside any warranty. When I asked about charges I was told TCW stands by its products and the only charge would likely be return shipping.

TCW diagnosed the problem, repaired it, and will be returning it to me for only the shipping cost. Kudos to Bob and TCW for the excellent support.

Now back to the real reason for posting -

An IBBS that is accepting no charge current will be slowly discharged since it is used at every engine start and likely also for database loading. The IBBS may have greatly reduced capacity if it is ever needed when the alternator fails. The IBBS voltage is in the green for this condition which is misleading. 12.9 V is an acceptable voltage when the IBBS is in use and being discharged. 12.9 V is not an acceptable voltage when the IBBS is not in use and should be accepting charge.

Recent updates to G3X software have added the capability to change scale color bands based on other external conditions. It may be possible to have two different IBBS voltage scales, one with color bands appropriate for "in use" and discharging, the other with color bands appropriate for not "in use" and charging.

If I'm able to implement this I'll post the details. (IBBS scale details are hidden in the standard config file - GEA 24 GP2 Not Configurable - but I have already reverse engineered the IBBS scale and made GP2 user configurable.)

[jjoffe@me.com]

I was at the hangar and loaded a new G3X database but didn't fly. That broke the normal routine and I managed to leave the hangar without turning off IBBS. It was a week before I found out and the IBBS battery did not seem to take any charge on a 1 hour flight. IBBS voltage did not rise above 7 V.

I spoke with TCW and had my fears confirmed. The battery is too deeply discharged for the charge controller to enable charging. Only fix is to replace the internal battery pack.

The good news, if there is any to be found, is that TCW now allows experimental IBBS owners to change the battery pack themselves. The manual I have on file says IBBS must be returned for battery change.

Andy hi
Just an idea here - when I purchased my earthX 1200 I also ordered an Optimate lifpo charger which claims the unit can recharge and wake up a deeply discharged battery- if you can get your hands on one it may be worth a try.
Goodluck
Julian

[Andy]

Just an idea here - when I purchased my earthX 1200 I also ordered an Optimate lifpo charger which claims the unit can recharge and wake up a deeply discharged battery- if you can get your hands on one it may be worth a try.

Once cell did not accept charge. The other 3 cells each charged normally with a single cell LiFePo4 charger. That pack has been cut open and will never go back in an IBBS. I may find a use for the 3 good cells in another project.

Edit to add - DO NOT use that charger on your IBBS. It may destroy the IBBS internal charge controller.

[Andy]

Recent updates to G3X software have added the capability to change scale color bands based on other external conditions. It may be possible to have two different IBBS voltage scales, one with color bands appropriate for "in use" and discharging, the other with color bands appropriate for not "in use" and charging.

I've been working on this idea, on and off, and I have a first draft requirement that I hope to implement soon. I've been looking at IBBS voltages for a couple of different IBBS units and the behaviour on charge is not what I expected. The main battery (SBS-J16) and the standard emergency ignition battery (2 AH AGM) are always charging when the engine is running but the IBBS is not.

The IBBS internal charge controller brings the battery pack to full voltage then shuts off and the voltage slowly decays towards the fully charged resting voltage. If the voltage drops below the charge initiation threshold then charging starts again. This means it is normal to see the IBBS voltage changing in flight even when the IBBS is not in use.

The two IBBS I have available have similar charge initiation and cutoff voltages but I do not know that they are typical of all IBBS units.

My longest FX-3 flight was during phase 1 and it was close to five hours. It shows the IBBS charge cycles very well -

[kshunz]

My FX-3 (#148) has a similar IBBS charge cycle, ranging from 14.2V down to 13.3V with a period of about 95 minutes.

[Andy]

So that's 3 IBBS with the same characteristic. Thanks for the confirmation.

It's a bit puzzling that the IBBs documentation says "A fully charged IBBS will indicate about 13-14.7 volts..". 14.7 V would be 0.5 V above the normal charge controller cut off voltage. 13.0 V, if continuous, would indicate a charge controller failure.

Maybe I'm oversensitive to this but I flew several flights witth a slowly discharging IBBS battery as the charge controller had failed. The voltage remained in green band and gave me no warning of the failure.