This sounds more like your DQ charger may not be set to the proper gel profile rather than anything you are doing to provide input power to the DQ charger.
Here are directions on how to check what profile your charger is set for:
https://support.delta-q.com/hc/en-us/articles/360015663051-QuiQ-Series-How-to-Change-the-Algorithm-Manually
Here is one of many lists of the profiles that exist, note, your charger will at most only have some of these loaded and may even have ones not listed on this sheet.
https://support.delta-q.com/hc/en-us/articles/360052952391-Charge-Profile-Algorithm-List
What are the specs on the GEL batteries you have installed? #6 is more common GEL profile for older GEMs that have similar GEL setups (six 12v gel cells)
@David_Illingworth is the Think guru here, maybe he knows where to find a list of profiles or has some first hand advice.
Rodney’s notes on how to change profiles on the DQ QuiQ charger via the tappy-tap-tap method if needed,