Re: AGM battery chargers vs normal battery charger?
I am not exactly sure what you are asking about...
Generally -- you have a power source (120 VAC, solar panel, etc.), goes to a Battery Charger (or Charge Controller) which may shift the power (from 120 VAC to 15 VDC) and provides current to a battery bank in an appropriate manner.
At least, from a definitional point of view--A Battery Charger and a Charge Controller are sort of the same thing...
However, there are many types of Battery Chargers/Charge Controllers out there that are designed for specific uses...
You have the normal Car Charger (120 VAC to 15 VDC).
You have simple Solar Charge Controllers (manage the solar panel current/voltage to the battery bank).
And you have sophisticated Solar Charge controllers (MPPT Type) which optimize the solar panel's I*V curve to the battery bank's I*V curve (maximize power transfer)...
There are even charge controllers that take energy from a 24/48 VDC battery bank and drop it down to charge a 12 volt battery bank (high voltage truck or something and 12 VDC accessory like a HAM/CB radio).
And then you have other specialized controllers (one common type known as a shunt controller) which "bleeds" power from the battery into a load (air or water electric heater typically) because the charging source (wind or water turbine) cannot allow to be "unloaded" or they will overspeed and self destruct. The turbine simply outputs as much power as it can into the battery bank + load--and the shunt controller turns on when the battery is fully charged and dumps the current into the load/resistor bank as waste heat.
And some of the Solar RE controller have multiple function and can actually be setup to operate either as a "pass through" or "shunt" controller--depending on the need of the installation.
So--if you have a particular application, describe your needs rather than trying to "fit" your need to a particular controller--I think we can help better that way.
20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.