Flooded batteries usually specify a float/maintenance voltage of 13.06 to 13.4v, at 77F battery temperature, so 12.96v is too low, and especially in colder locatiions.
I would disconnect it.
My AGM battery specifies a float voltage of 13.6v.
When i would float it fully charged at precisely 13.4v at arounf 77F, when I would bump my charger to 14.7v, the amps the battery accepted indicated that the battery was somehow being slightly discharged despite being held well over its full charge resting voltage.
When I set it to 13.60v float voltage, then goose voltage to 14.7v, amps quickly tapered back to near Zero, indicating the battery was still at full charge.
This indicates 2 things, One, that the proper float voltage for the specific battery at the battery temperature is very important, and 2, that an accurate Ammeter is pretty much manditory if one truly wants to know what is going on with their charging source.
If a float/maintenance charger is not able to compensate for either ambient or preferably battery temperatures, I would disconnect the charger from float maintenance duty when temperatures fall below 60F, and simply choose to hook it up every so often to recharge back to 100%, then remove float charger again.
Those whose ambient temperatures vary widely should really seek a temperature compensated charging source,if they are trying to get maximum lifespan from their batteries.
Obviously many do not bother, nor care, nor are aware, and do 'just fine'.
So picking Fly scat from the pepper is upto the end user.
