mena661
Southern California
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In one of the threads, I believe Pianotuna posted a link to batteryuniversity.com. What got my attention was the info on acid stratifcation. This is of importance to me in particular because my batteries are tall and prone to stratifcation. I have been given advice from Mexbungalows to perform an occasional charge at 14.7V for a couple of hours to keep that at bay/reverse it. What I found interesting at that link was their suggestion to let the batteries sit without a charge on them or tip them.
I experimented with letting them sit. At the start of the test, the SG of the batts was at 1.300 @ 63F and voltage was 13.00. This was after disconnecting them from a float charge for about 16 hours. According to a spreadsheet I have, the SG should be closer to 1.273 (at 60F). Also, when I baselined the batts I got a SG of 1.275 @ 68F at 12.8V. So I think it's fair to say they were stratified.
After two days, the SG was 1.290 to 1.295 at 65F (12.77V). The thrid day was still around 1.285 on two batteries and the other two were at 1.295 (62F, 12.78V). The fourth day is where I saw one battery drop to below 1.280 (above 1.275) while the others were at 1.285 (70F, 12.78V). The fifth day two batts were below 1.280 while the other two were just below 1.285 (74F, 12.78V). Today two batts were just below 1.280 and the other two were at 1.275 (58F, 12.8V).
I put them back on float. I'll check them later next week to see what their SG is. Hopefully, they won't be stratified. If they aren't I may use this method instead of the 14.7V charge.
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RoyB
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Mena661 - When you say "TIP" this is not very far I suspect. You wouldnt want to turn one upside I would think as some readers might think you are meaning..
Maybe just around 45 degrees of tipping or maybe even less than that???
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mena661
Southern California
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RoyB wrote:Mena661 - When you say "TIP" this is not very far I suspect. You wouldnt want to turn one upside I would think as some readers might think you are meaning..
Maybe just around 45 degrees of tipping or maybe even less than that??? Most definitely don't tip too far. I don't think it would take much.
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BFL13
Victoria, BC
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The ref says to tip "on its side." The idea is to get the bottom stuff to flow ( it is slow) to the top, so 45 degrees won't help. I tipped my 27s routinely as a way to destratify and it worked. I tipped them up on end though. Waited 20 minutes and tipped them up on their other ends wait 20 minutes and see if SG is up from before. worked great.
I don't undrerstand what mena661 did in that trial in the OP. I can see they started to lose their surface charge.
How can reduction of SG be a sign of destratification when it is the stuff at the bottom that has the highest SG, not the stuff at the top you get with the hydrometer?
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mena661
Southern California
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BFL13 wrote:How can reduction of SG be a sign of destratification when it is the stuff at the bottom that has the highest SG, not the stuff at the top you get with the hydrometer? I was under the impression it was the opposite.
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Supreme Oppressor
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SG of 1.0 is water which would "float" on acid if stratification were to occur. Taking SG at top and bottom of the cell would be the only real way to tell. The SG changes indicated are very small and could be attributed to other causes.
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BFL13
Victoria, BC
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I wonder now if 'baseline' SG is valid. Perhaps as the batteries are broken in with that greater spongey area being created, they would have a higher SG. I don't have a clue.
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Chris
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So I ran 4 6v 260 amphr Dyno's in my boat for 9.5 years without equalizing. In talking with Dyno while purchasing 6 news ones I told them that I never equalized the set of four. He asked how I charged and used them. I said never below 50 percent of the amphours available and charged with a 140 amp alternator with smart regular or with a 75 amp four stage charger in my inverter. He said you are fine, and have no need to equalize them, as they are getting "stirred" well the way I am using them. Chris
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mena661
Southern California
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BFL13 wrote:I wonder now if 'baseline' SG is valid. I'm wondering now too. I'll do some periodic measurements and see what the SG looks like. If it stays high then that's probably going to be the new baseline.
Supreme Oppressor wrote:SG of 1.0 is water which would "float" on acid if stratification were to occur. Taking SG at top and bottom of the cell would be the only real way to tell. The SG changes indicated are very small and could be attributed to other causes. Probably the changes are because they weren't on float anymore and attributable to self-discharge.
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mena661
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Chris wrote:So I ran 4 6v 260 amphr Dyno's in my boat for 9.5 years without equalizing. In talking with Dyno while purchasing 6 news ones I told them that I never equalized the set of four. He asked how I charged and used them. I said never below 50 percent of the amphours available and charged with a 140 amp alternator with smart regular or with a 75 amp four stage charger in my inverter. He said you are fine, and have no need to equalize them, as they are getting "stirred" well the way I am using them. Chris Mine have never been below 80% SOC and I keep them on a temp compensated "smart" charger. None of those things keeps stratification at bay on a tall battery. My batts are a good 6 inches taller than a GC. GC's do suffer from some stratification but not like these do. Since I was wrong in my thinking on stratification, the only reason I can see for the increase in SG is the formatting process mentioned in that article. Looks like my baseline measurements were for a green set of batteries. And maybe my batteries might have been a little sulfated when I got them.
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