The danger of mixing battery types is this.. Battery charging is actually a science.. Now some converters (parallex 7300 no T) put out a constant voltage which is never the right voltage..
Other converters (Progressive Dynamics with Charge wizard) put out a voltage that is dependent on the battery needs (Bulk/Absorption/Float) and some others (Xantex Prosine inverter charger module) you can program,
For each type of battery, Deep Cycle, Starting, Combination,, AND in each of those you have Flooded, Maintenance free, and AGM and in some cases different manufaturers as well.
The settings are different.
Using the wrong setting means that either one type of battery is not fully charging, or the other one is over charging, in either case, this is not a good thing.
What's more among the starting/deep/combo types. different discharge cutoffs apply as well.
So it's all about care and feeding of the batteries.
