As said , use a 90 amp, although bulk charge in any short time kills any and all batts.
3 doors where designed with there power requirements in mind.(what went wrong with fans!)
Running a 044 fuel certainly increases demand from your alternator along with high power amps etc.If the feed cable(to Batt) has seen better days and losing efficiency due to resistance/heat the situation is amplified.
I recently replaced my charging feed cable from my alternator to my battery and gained a volt over a cable distance of two metres!


Food for thought, cable is no different to a water pipe where flow=amps/current/voltage=pressure/resistance=size.


Sorry for going off on one.


My Best.

Tim.