Our team has four CTEK MXS 5.0 battery chargers. Up till now we have used them in the conventional mode. Just recently I have noticed the CTEK charger has a AGM mode. Now I didn’t know what this was until I looked it up. I have always assumed the Greenpower batteries are a gel electrolytic and AGM was for some funky new car battery technology. AGM stands for Absorbent Glass Matt and it turns out the Yuasa Greenpower battery has this technology inside it. Still a bit sceptical so I turned to the datasheet of the battery. This says that for cyclic or boost charge the voltage should be 14.52 V (+/- 3%).
Now the CTEK charger handbook as a handy diagram showing the charge states. See below:
This shows that in AGM mode the charge voltage is 14.7 V and in normal mode 14.4 V. So it looks like AGM mode is within the 3% margin of the battery so shouldn’t cause it damage but the normal charging mode appears closer to the 14.52V the battery prefers.
So my question is what is the point of this AGM mode and will it make a difference to either increasing the energy stored in the battery or reducing the battery's lifespan.
Interestingly for float mode the charge voltages are identical in either mode.
See link for more details about AGM.https://en.wikipedia.org/wiki/VRLA_battery