Ben Covington wrote:

Does anyone know if I can replace my 6 volt lead house batteries with 6 volt AGM batteries without modifying my charging system on a Discovery? Ben Covington 

Yes, you can.  The only thing you will need to do is change the settings of your inverter to let it know you now are using AGM batteries.  It's very easy and takes only a minute.  Refer to the inverter manual on how to change the setting.

I’ve upgraded to AGM house batteries in my ‘17 Discovery 39g and I’m not sure how to set the firefly to the proper settings. I’ve changed the charger setting to “AGM” but not sure about the AH setting. The batteries I installed are 235 ah, but the firefly has choices ranging from 200 and up. What number am I looking for on the ah settings?