maximum dc voltage output Magnum 3012 with remote

Try 14.9 next time you run them down a bit. Is there a second limitation by battery type etc? Maybe reduce the amp rating to 50% of max.

If your battery is at or near charge capacity of 14v, your voltage will be regulated down from 15.4volts. If your battery was sitting at a lower capacity such as 10volts when you would see higher charging output voltage. This can usually be confirmed by using a volt meter while briefly disconnecting the positive lead from the charging source simulating a fully discharged battery. This would command 15.4v max charge. Running the charger like this for an extended time could cause damage.

Hi,

The banks were at 19.5 C, so I think it is not temperature related.

It may have been limiting due to temperature. I know those will do well over that voltage for equalization.