The unit I let the smoke out of, intentionally might I add, was the Etopxizu 23$ cheapowatt 30 amp power supply, which had NO overvoltage, overcurrent/overtemperature protections built in.
The Megawatt has those protections built in, but I would certainly recommend increasing ventilation if hooking it to a depleted battery which can max it out for more than 5 minutes.
When I say intentionally, I mean I got tired of twiddling the voltage pot to keep its amperage below 36.2 amps but up near that level, above which there would be some unnatural sounding buzzing occurring. I had by this time wired up an external potentiometer a better 60Mm fan, and had an Ammeter inline, so voltage twiddling was not the ordeal it is with the tiny 3 cent pot the unit came with, buut it was still enough that I said screw it, and set it to 14.9v unloaded, then hooked it to the well depleted screwy 31, and after 17 minutes of 38+ amps, the magic smoke escaped and I ordered the meanwell rsp-500-15 which has been fully charging my batteries, or floating them at the voltage I have chosen, ever since.
And I disagree with a 24 hour resting voltage as dictating full.
The screwy 31 has been off the charger for 48+ hours and is reading 12.92v, and 24 hours ago was at 12.94v. I know eventually it will settle to 12.78v, and this is with one cell that will never get above 1.265 SG.
Battery temperature plays a huge part in how soon resting full charge voltage settles to what it should be.
Use an Ammeter at absorption votlage to determine full, not a 24 hour resting voltage. Not without the battery temperature and previous experiences with that specific battery to compare to.
The beauty of these adjustable voltage power supplies is that one can hold absorption voltage until those amps taper to the 'full' point. Once full is established by the ammeter at a temperature compensated absorption voltage, then one can watch the resting voltage fall, and take notes as to how quickly it fell to what it ultimately levelled out at, At that specific battery temperature, and then make future comparisons, on that specific battery.
