periodically to make it stay at the "float" level. My Mastervolt unit is currently send 0.1 amps average to the our 880 amp hours of house batteries (four 4D AGM Lifelines). The "float" voltage of the batteries is 13.74 volts -- as I look over at the reading(s).

The actual draw on our (inverter/)charger in float mode is more complicated. The current "house" draw of the connected load of our lights, computer, nav equipment, etc. is running at 22 amps. So the charger is "floating" to the batteries, while putting-out enough power to "float" the batteries.

It's obviously a function of watts = volts x amps (or a variation of that algerbra). The charger says its actually sending 13.9 volts out at 31 amps -- but it's only getting a .01 amps to the batteries (which say 13.74 volts.

The house bank plus the current load influence one another -- that's why you have a lot complicated features on a smart charger.

The Xantrex (Heart of olden days) and others do the same sorts of things.

One test is the temperature of the batteries. Your Heart 2000 may not read that out to you (but our Mastvolt shunts do). If your batteries get HOT to touch (or lead acid batteries that boil-off water), then something is wrong.

The two drawbacks of AGM or Gel Cells are: 1) Higher cost; and, 2) they don't give you a lot of external warning if you are overheating them. Our Mastervolt system shows the battery temps on the two banks. Heart has temp sensors which give you a shut-down, reduce charging, or an alarm (as I recall).

In Rodd L's case -- watching the fluid levels and seeing if he notices a change in the performance of his charger's output and patterns of performance should provide him with the info he needs.