AGM Battery Suggestions - Good, Better, Best?

KenMast wrote:
Hi scrubjaysnest,

Thanks for your comment. I'm a novice when it comes to RV batteries and I don't really know what you mean. Would you be so kind as to go into further details. I assume that the batteries would charge the same as my current battery does. What am I missing? Thanks a lot for any more information that you can provide.

Ken

The quick answer is for the Surrette 12 volt AGM, 14.7 volts charge and 13.65 volts float at 77 deg F
The long answer is a chart of current and voltage over time.
One has to go the manufacture's web of a given battery to get specific charging specs.
My Exides are 14.5 volts boost or bulk charge and all the current the battery will take up to 5 X c/20 rate; or c=105AH there for 5*105/20 = 26.25 amps. That covers the first 80%. Absorb gets the next 20%; volts is raised to 14.9 and held there until current drops to about 1 amp at which time you shift to float or 13.3 volts.

The only two converters that come close are the Iota and Progressive Dynamics and they aren't very close. Iota with the IQ4 pendant is 14.5 volts boost for an hour then drops to 13.6 volts for absorb if I remember correctly. Some of the PD models have a manual over ride that lets you keep boost going longer. But their absorb voltage isn't high enough either. Forget the WFCO converters, some folks have apparently tricked the WFCO's into boost by having two or more batteries, run them down below 50% state of charge and turn on every 12 volt appliance in the camper. Never worked for me.

The above is if you want to get maximum life out of the batteries. A quality flooded or AGM properly maintained has an expected life of 6 to 10 years.

Each battery maker has different requirements to maximize battery life. But ball park is 14.5 volts boost or bulk charge; 14.8 volts absorb charge and 13.4 volts for float. AGM's don't require equalizing but flooded lead acid do and that voltage 15.0 or higher.

Check out batteryfaq.org for detailed answers. The site is updated about every 6 months. Another good source is solar-electric.com in their faq section. They are also a vender. Their forums section has a lot of good information on solar projects, grid tie, off grid and RV.