JVISS wrote: Regarding your comments on AGM, I would like to see a reference that supports that. What I have read from authoritative sources is in contradiction, specifically, that AGM charge faster, and go to 80% depth of discharge for the same life cycle as flooded taken to 50%.
- You say "forever." Can you be more quantitative, please? I haven't seen in the literature that it takes 'forever' to put back the last 7%, and - compared to what technology?
- You say you increase the likelihood of sulfating if you don't charge them up frequently, yet, AGM are known to have better storage characteristics, and lower self-discharge than flooded.
- The paragraph that starts "When we go to beyond 60%," doesn't make any sense to me at all. There's a lot of qualitative criticism, like "a lot," "declining," and "painful," but nothing one can really go on. Perhaps you can elaborate?
I've had three sets of Lifelines 4D AGM's over the last 19 years. The first set (with a Heart 2500 Combi lasted 8 years). The second, 4 years; and, the third two years; and the fourth, 1 year. Between the second and the third sets, I upgraded to more robust MasterVolt (nominal 200 AMP) Combi unit. I almost always charge the batteries to "full" from the generator or at shore power.
With both the Heart (now, Xantrex) and the Mastervolt, I have personally watched the acceptance voltage through the recharging cycles carefully. The Mastervolt is easier to tweak the voltages and monitor the amps in and out than the less robust (nominal) 130 amp "advertised" Heart's capacity.
However, if you watch to see what happens with the real world acceptance voltage, you'll see the declining curve of actual amp hours into the battery as you move to increased charge levels. That's when the batteries are fresh "out of the box".
To get the batteries up to 95% takes a long time (which you measure in hours, not minutes) even if you have 130 amps of actual "real world" charging capacity available to get to the batteries. (The 2500 Xantrex, though rated at a nominal 130 Amps never really puts out much more than 65 or amps to the house load after it gets settled down, for example.)
I recharged my Lifelines at 14.4+/-Volts (At the battery terminals in Bulk Mode). The batteries just have naturally slower acceptance rates as they move up the charge "curve".
I've consulted with two sets of marine electrical "experts" and others comments. In calls to Lifeline, they have said over the years, in essence, "that's just normal".
It's faster in cooler 55-60 degree water than 80 degree water, but the real world acceptance rate is lower. If you don't charge the AGM's back up very regularly, you'll be sorry.
JViss: How would you chart your acceptance rate from a 50% through 100% recharge? How many hours does it take to get your batteries back up to above 95% when under shore power and at with what equipment. When you're under way, with an alternator, what's been your measured experience?
[By the way, I have been a proponent of the AGM technology. The Lifelines had a stellar reputation and I've supported them. However, ask yourself: Why, with the same batteries, do you they recommend that you EQUALIZE them regularly -- even if you charge them back up to over 95% almost always; and store them at near 100% capacity on a very controlled system)? Something has changed in their manufacturing process. I've read the same materials that you've cited.]