I just looked at the Trimetric manual for the new version, which I think has different settable the parameters than I remember. I don't see the time requirement setting for indicating full charge, or going to float if it is doing solar charging, but it does have the % overcharge setting that might work for the same purpose to some extent. The problem is that the % of extra AH you need to put into the batteries changes with DOD, so that would be an issue.
All the internal amp measuring chargers don't let you program things like the % overcharge or any extra time, AFAIK. If they had a 3 stage program with full shutoff after a float time, you could put the float voltage high and set the timer to whatever extra time you wanted.
The idea of going longer in absorption is interesting to me, as I did a lot of experimenting with the idea when we got the Magnum and Lifelines, only not doing it with extra time.
I had always checked the ultimate ending amps of our wet cells, when we had them, by dropping the ending amps to zero with the Blue Sea charger because Trojan was pretty firm in stating it would change quite a bit as the batteries aged. We found it did change a lot on the 12v versions, but hardly at all on the 6 volt GC versions, which was interesting.
I did the same test with the Lifelines after they had been cycled a few times to break them in, and found that they would actually go to nearly .2%C amps if left on long until the amps stabilized, which is quite a bit lower than the .5%C where Lifeline considered them full in tech manual. Going that extra nearly .3% lower essentially doubled, or more, the charge time by adding at least 12 hrs in absorption to about a full day.
I called Lifeline about it and asked if they should be taken that far in absorption or if it was better to stop at the .5%C to limit their higher voltage exposure time. They were a little squishy on it, but thought that being at elevated voltage that long would not be a good idea on a regular basis because of increased corrosion potential. For deep discharge use, they would prefer the "mini equalization" stage at the end of the cycle instead. In normal type use they said the batteries would get to essentially the same state of charge and condition on float as they would with the longer absorption, but it would take a long time to get there, like days.
Being me, I went back to test what they said by doing it both ways. First I did the long absorption time to get to lowest amps I could. I then took it to float with a only the tiny load of the remote panel and our detectors on. It took a while to get near float voltage, but when it did I turned off everything but remote panel and checked at just about .2 amps on the 440ah bank.
I then ran the batteries down over a couple of days to 50% and did the recharge at the normal ending of .5%C and then let it go to float slowly the same way. When it got to steady float, it was in the .4 amp range, which was double what the long absorption had given. After about 2 days at float it was around the .2 amps, and after a week or two had actually gone closer to .1 amp.
Based on the test, I did decide that Lifeline was probably right, at least for their batteries, and have been using the .5% and letting the float finish them off. I think it has been about 3 years and they still eventually get to the same .1 amp at float, so seems to be OK.
I think if we were on the road and getting deep discharges all the time (which is very unlikely with our settup), I would probably throw in a manual tiny equalize at about 15v every once in a while, but we have never had conditions that would warrant that to this point.
If your charger can do it, you may want to manually run a very short high voltage cycle at the end of absorption once in a while and see if it does what you want, without using the longer absorption time.
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