Join Date: Sep 2008
Location: Victoria B.C. Canada
Thanked 109 Times in 100 Posts
Rep Power: 10
Adjust what from 12.5 to 15.5 volts? 12.5 doesn't charge anything. And 15.5 it too high to charge any battery.
For charging different battery technologies need different voltages for the different stages of charging.
The Powermax is fixed at the settings for flooded batteries as most of the RV's that are its intended market probably have flooded batteries.
Below are the voltages for the various types of batteries on a Xantrex Truecharge2 charger. You can see the differences. The Xantrex is about $300 for the 40 amp version, their most popular. I have installed quite a few of these. More expensive but they take good care of your batteries, even have an automatic equalize function. More $ for the charger but the batteries could well last longer, especially if they are not the flooded type. Good batteries taken care of should last 6 to 9 years but I have come across older batteries still going strong. f the batteries life is shortened you haven't saved much money.
There are other brands of chargers with settings for all types of batteries for less than the Xantrex.
Below that is the panel on the charger for adjustments which includes the temperature setting at the bottom.
At the bottom are the settings the Powermax is fixed at.
Living aboard in Victoria Harbour