Amps jumping around on AGM finishing charge
At a battery temp of 81 degrees and a float charge of 13.33v, the charge was settling in toward .1 A when it started jumping around more and more. Still settling, but jumping from .02a to .15a. The ...
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My theory is the amps bounce each time a drop of water falls from the catalyst inside a cell. There is really nothing else discontinuous going on in the system I can think of.
I don't hear any bubbling at all. My reading literature (especially setting up AGMs as standby battery banks) told me that AGMs probably gas a little, far more often (but undetectably) than people think, so I came up with a way to detect the bubbles by placing the valves under distilled water.
Mine will stay at .01a for a long time then drop to unmeasurable - that is 2 paralleled new 92 Ah Dekas.
I think the batteries are not quite charged too mena, despite sort of first glance indications that they are. Thanks for the encouragement! I have basically found 3 modes.
1) 4 digit (hundredths of a volt) temperature corrected float. Tiny micro bubble from just 2-3 of the cells, very infrequently. Pin head bubble from one of them maybe every 15 minutes or less often. I think this is just green batteries settling in. A chemist could say how much water is lost but the volume is very small because of the large amount of H and O even A gram of water will create. Presumably normal for break in.
2) above float up to lowest charge voltage of 13.8v, .05A-.15A charge rate, volatile value hops all around a few minutes after charging starts. Not dropping voltage back to float will cause a few bubbles a minute total, but *all* cells generate the occasional bubble. I believe this is charging too fast- breaking in the green cells is supposed to end up evening them out. All bubbling makes me think this is just overcharge. Still would not be detectable without water on the valves, still very low gas volume, but not something I want to see. At all. The normal directions are to charge a string before placing it on float, but I am going to see what just being on float for more hours does.
3) above .15a charging when approaching very full, 1 degree post or valve temp increase. Similar to above but does not totally stop the bubbles for an additional few minutes after voltage is removed. Useful in a pinch, but more lag in detecting venting.
Now that I can float more easily and to a tighter voltage with the buck converter (with manual temperature correction), I am just going to float and watch, periodically checking the rest voltage.
Jim
I don't hear any bubbling at all. My reading literature (especially setting up AGMs as standby battery banks) told me that AGMs probably gas a little, far more often (but undetectably) than people think, so I came up with a way to detect the bubbles by placing the valves under distilled water.
Mine will stay at .01a for a long time then drop to unmeasurable - that is 2 paralleled new 92 Ah Dekas.
I think the batteries are not quite charged too mena, despite sort of first glance indications that they are. Thanks for the encouragement! I have basically found 3 modes.
1) 4 digit (hundredths of a volt) temperature corrected float. Tiny micro bubble from just 2-3 of the cells, very infrequently. Pin head bubble from one of them maybe every 15 minutes or less often. I think this is just green batteries settling in. A chemist could say how much water is lost but the volume is very small because of the large amount of H and O even A gram of water will create. Presumably normal for break in.
2) above float up to lowest charge voltage of 13.8v, .05A-.15A charge rate, volatile value hops all around a few minutes after charging starts. Not dropping voltage back to float will cause a few bubbles a minute total, but *all* cells generate the occasional bubble. I believe this is charging too fast- breaking in the green cells is supposed to end up evening them out. All bubbling makes me think this is just overcharge. Still would not be detectable without water on the valves, still very low gas volume, but not something I want to see. At all. The normal directions are to charge a string before placing it on float, but I am going to see what just being on float for more hours does.
3) above .15a charging when approaching very full, 1 degree post or valve temp increase. Similar to above but does not totally stop the bubbles for an additional few minutes after voltage is removed. Useful in a pinch, but more lag in detecting venting.
Now that I can float more easily and to a tighter voltage with the buck converter (with manual temperature correction), I am just going to float and watch, periodically checking the rest voltage.
Jim
