The problem with those power supplies as battery chargers, is they are regulated to 13.8v.
That is less voltage than what almost any flooded or AGM battery manufacturer recommends to achieve a full charge on their batteries.
Most 3-stage chargers will do a bulk to 14.4v to 14.8v (depending on who made the charger) and then drop to 14.2v for some hours for the absorb stage, and then drop to 13.2v to 13.8v (again, depending on who made the charger) as the long-term float (maintenance) stage.
So even if the power supply puts out 36a (peak, this would drop off as the battery voltage rises toward 13.8v), it's not going to get the battery fully charged because it will never push the voltage high enough to fully activate the chemistry (never reach full absorption).
It will work to get the battery to 85% or so of a full charge, and will hold it there as long as there is less than 36a of loads on the battery.
But taking the battery to 85% instead of 100% will increase the rate of sulfation, and will not extend the life of the battery as much as it would be extended if the battery were regularly pumped up to 100% with a proper charger.
