Firefly oddities

[Pahaska]

When I happened to select the home screen of the main Firefly display today, my chassis battery was reading zero. I had previously disconnected and reconnected the ground by the accelerator pedal while installing the Blue Sea BIM.

The voltage at the 2 amp fuse on the coach side of the BIM read correctly. I pulled the cover of the main Firefly board and the connector for the coach battery and generator hour meter was in place and secure. I pulled that connector and the correct voltage for the chassis battery was there. I plugged the cable back in and the main Firefly display showed the correct voltage. For whatever reason, the Firefly did not detect the chassis battery coming back on line, but hot plugging it made it work properly.

The coach battery voltage on my main Filefly display reads about 0.4 volts low, compared to the chassis side and the Magnum display just above. My meter confirms that the Magnum display is correct. The BIM is actively connecting the two batteries and they should read the same. I think I have a defective Firefly board. The low reading can be a bit scary when not connected to outside power.

[Alex AVI]

Originally Posted by Pahaska

I had previously disconnected and reconnected the ground by the accelerator pedal while installing the Blue Sea BIM.


The coach battery voltage on my main Filefly display reads about 0.4 volts low, compared to the chassis side and the Magnum display just above. My meter confirms that the Magnum display is correct. The BIM is actively connecting the two batteries and they should read the same. I think I have a defective Firefly board.

JOHN - did you disconnect house Gnd too?

I have had my coach batteries read 0.4 low compared to chassis, but that's when the banks are disconnected and depends on SOC of each bank and where in the charge cycle they were at the time, epsecially since I leave fridge on all the time and roof vent fan running when hot weather. But I do not remember if there was that difference compared to Magnum display. But also, they should only be the same if the BIM has them connected. So this voltage differential is happening while both banks are connected or disconnected? May need to call Firefly and ask if you have to calibrate. May want to check what your SeeLevel II display reads for voltage also. It is buried behind the panel or inside one of your overheads.

[Pahaska]

Both the chassis and the coach grounds were disconnected while I replaced the BIM. I had noticed the difference before I replaced the BIM.

They should read the same when the BIM has the batteries connected. I might check with Firefly to see if they can be calibrated. I see no indication on the Firefly board.

[Alex AVI]

Originally Posted by Pahaska

They should read the same when the BIM has the batteries connected. I might check with Firefly to see if they can be calibrated. I see no indication on the Firefly board.

JOHN - Agree. Should match. Yeah, see no obvious calibration on Firefly board. But my understanding (and personal discoveries of sensor is the Firefly is just a graphics layer (GUI) on top of existing sensor