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#1
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posted to rec.boats.electronics
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Ping - Larry The Cable Guy, or should I say Larry The Charger Guy.
Larry, In past posts you've mentioned that most batteries don't die of old age, that they're usually mistreated in one way or another and killed prematurely. I've listened to that advice, have been careful with my batteries, and they've treated me pretty good. Well, last weekend when I got to the boat I noticed I forgot to open the main battery disconnect when I left the previous weekend, and the battery that supplies the stereo system was DEAD! I wasn't surprised, but I knew what it probably meant, and sure enough it won't take a charge now. I haven't tried an old fashioned charger yet, but I did try my Schumacher 12 Amp Ship to Shore Supreme Fully Automatic. http://www.batterychargers.com/detai...%2DPE&catid=21 It's not the end of the world, it's only 1 deep cycle battery, but it was only 14 months old, so in that respect it kinda hurts. Anything I can do to get _some_ life back into it? Question #2) Not relating to previous question, this is just a general charging question for decent batteries. You've also mentioned in past posts that it's better to charge a battery slowly. What I usually do is leave one battery on the charger at the dock when I leave for the weekend. The Schumacher Fully Automatic allows me to do this and not worry about it even if I don't come back for two weeks. But even if I do come back the following weekend it's still been on the charger for 4 or 5 days minimum. I don't use my batteries in banks, I use them singly in different areas of the boat, so is there a smaller(amperage) charger that is fully automatic that would work better for me in that application? Being that the battery will always have at least 4 days to charge I'm thinking it might be better to use one that is less than 12 amp capable. What do you think? |
#2
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#3
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![]() Larry wrote: Open the stubborn "maintenance free" caps by prying them out and look in the cells to see if they're dry. Don't fill them. Add DISTILLED WATER ONLY until it just submerges the plate tops, a little at a time. Any cell the plates are still submerged, leave it alone until we're done. We can't charge battery plates that aren't submerged. Isn't any portion of a plate which has dried out, permanently damaged and unchargeable? The rest of the "dead" battery may be rechargeable, but the battery's capacity is reduced. |
#4
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"Mark" wrote in news:1156734601.788399.316510@
75g2000cwc.googlegroups.com: Isn't any portion of a plate which has dried out, permanently damaged and unchargeable? The rest of the "dead" battery may be rechargeable, but the battery's capacity is reduced. Nope. It just lost contact with the electrolyte, so is unable to be in the current stream to recharge. As electrolyte is recovered in charging, it gets deeper, so we don't want to fill a discharged battery because it will overflow by the time charging has recovered it. -- There's amazing intelligence in the Universe. You can tell because none of them ever called Earth. |
#5
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![]() Larry wrote: "Mark" wrote in news:1156734601.788399.316510@ 75g2000cwc.googlegroups.com: Isn't any portion of a plate which has dried out, permanently damaged and unchargeable? The rest of the "dead" battery may be rechargeable, but the battery's capacity is reduced. Nope. It just lost contact with the electrolyte, so is unable to be in the current stream to recharge. As electrolyte is recovered in charging, it gets deeper, so we don't want to fill a discharged battery because it will overflow by the time charging has recovered it. I understand that a discharged battery shouldn't be topped of with water for that reason, but it's my understanding that once a plate is exposed to air and dries, it is irreversibly sulfated and will not contribute to the battery's capacity again. From a University of Washington paper: "If plates are exposed above the electrolyte then the capacity of the exposed plate areas has been lost and cells will likely develop short-circuits because of plate shedding. Batteries with exposed plates should be replaced." You seem to be saying exposed plate area can be recovered by recharging. That's apparently not so. I once accidently exposed about 50% of the plate area on a battery, and it lost about 50% of its capacity; soon thereafter it died due to shorted plates, probably from plate shedding. Exactly as the UW paper described. |
#6
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posted to rec.boats.electronics
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"Mark" wrote in news:1156829173.178462.265980
@h48g2000cwc.googlegroups.com: From a University of Washington paper: "If plates are exposed above the electrolyte then the capacity of the exposed plate areas has been lost and cells will likely develop short-circuits because of plate shedding. Batteries with exposed plates should be replaced." You seem to be saying exposed plate area can be recovered by recharging. That's apparently not so. I once accidently exposed about 50% of the plate area on a battery, and it lost about 50% of its capacity; soon thereafter it died due to shorted plates, probably from plate shedding. Exactly as the UW paper described. In order to "sulphate", conversion of lead metal into lead sulphate, it takes sulphuric acid, not air. Lead sulphate is suspended in the solution of the electrolyte, after it has released its electrons to us. I don't see how exposing lead to air can eat it away. That's what the posts are doing all the time, and they're lead. No, I disagree with the professors, I'm afraid. Using a battery with low electrolyte eats away the BOTTOM of the plates, sometimes bad enough to eat holes in them we cannot recover because the electrolyte still has the same acid it started out with, in a more concentrated form, and the electronics freed must come from the plates still submerged, eating them away far worse than the engineers intended. So, if anything is "damaged" or "unrecoverable" it MIGHT be the submerged portion of the plates, not the exposed-to-air top, which won't get eaten away discharging at all. See my point? It's the submerged part that needs to be recharged very badly, not the exposed part. But, alas, we're talking of extreme conditions, not the conditions in your boat. You don't discharge the battery severely, or I hope you don't. You also didn't let the battery get THAT FAR down in electrolyte, just a little below the plates, exposing them. When you submerge these plates, that haven't been holed permanently, with DISTILLED WATER ONLY, please....The battery will nicely recover, after a few charge/discharge cycles, to its soft plated old self, the tops of the plates resoftening by the cycling, like we're SUPPOSED to do to a brand new battery that's just had its initial electrolyte charge poured into it. Of course, noone in reality ever does a proper cycling of a new battery to soften up those plates. That takes too much time from our busy life. The dealer doesn't do it, either. He pours the electrolyte pack into the holes, helter skelter, and never checks the gravity again to see which cells are really hot and which are not-so-hot...caused by differences and impurities in the plates. If we had any brains, we'd dump this crap and go back to "Edison Cells", those Nickel-Iron-Potassium Hydroxide beasts just outside my hamshack. Mine were made in the late 40's for a telephone system and STILL have the capacity stamped into the cases....(c; Ni-Fe batteries are only bad for the battery business....never needing constant replacing and recycling as Pb's do....the reason they just HAD to be eliminated. http://www.beutilityfree.com/battery...tery_flyer.pdf Don't worry about how deep you discharge them. Recharge them when the lights get too dim...(c; It doesn't hurt them at all. You don't even need a regulated charger. -- There's amazing intelligence in the Universe. You can tell because none of them ever called Earth. |
#7
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![]() Larry wrote: . . . Schumaker SE-1-12S "1.5A Fully Automatic Onboard Battery Charger/Maintainer". I'm wondering, would one of these things fully charge a discharged *big* bank of lead acid batteries, like 500AH capacity? It'd take 20 days or so, but could it do it without harm? Would the gentle charge rate stop sulphation during the 20 day charge? A half dead lead acid battery sittin' around for 20 days would sulfate up with *no* charging going on. And could 1.5 amps drive the batteries up to 14.2 volts? Never tried such a thing - tiny charger, big batteries. |
#8
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"Mark" wrote in news:1156735487.090872.131750@
74g2000cwt.googlegroups.com: I'm wondering, would one of these things fully charge a discharged *big* bank of lead acid batteries, like 500AH capacity? It'd take 20 days or so, but could it do it without harm? Would the gentle charge rate stop sulphation during the 20 day charge? A half dead lead acid battery sittin' around for 20 days would sulfate up with *no* charging going on. And could 1.5 amps drive the batteries up to 14.2 volts? Never tried such a thing - tiny charger, big batteries. No harm at all. This charger completely shuts off when the red led comes on at 14.2V and doesn't come back on again until the cell voltage drops to around 13.2V. The charge you get is very deep, penetrating the plates very nicely. Nothing stops sulphation, a natural occurance no matter what you do. To greatly reduce sulphation, the cure is to never discharge the battery below 50% of capacity. The bigger the battery's capacity, the less you'll be discharging it, so it sulphates (or sulfates??) less. It will only sulfate when when the lead sulfate in suspension gets saturated enough the ions form crystals that gravity falls out into the bottom. You leave your car battery "half dead" all the time...short trips, moving the car, the fans running long after you've shut down the engine drawing 30A cooling the radiator, the headlight delay shutdown drawing 20A so you can get inside for many minutes. The recharging, even at the slow rate, will cause the ions in suspension to stay in suspension. If this little charger had no automatic shutdown, I'd never suggest leaving it charging 500AH batteries as it would overcharge them, eventually...after that 20 days. One of the benefits of very slow charging is it never heats the electrolyte. The batteries, here in the South, are kept too hot in the first place inside an engine room at 120F with the boat sitting in the sun. Slow charging keeps from exascerbating the problem. You must also consider any discharging loads like bilge pumps that cycle on and off when you're not in the boat, before you consider if this little battery charger is a good idea. If you're charging at an average current of 1.5A and the loads are averaging 2A, that isn't going to work and you'll arrive at the boat with dead batteries, ruined. The poster that started this, I assumed, has a boat on a trailer with everything shut down. If you forget one good light, the charger will not recharge and may even lose the battle, killing the batteries....not good. -- There's amazing intelligence in the Universe. You can tell because none of them ever called Earth. |
#9
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posted to rec.boats.electronics
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![]() Larry wrote: "Mark" wrote in news:1156735487.090872.131750@ 74g2000cwt.googlegroups.com: I'm wondering, would one of these things fully charge a discharged *big* bank of lead acid batteries, like 500AH capacity? No harm at all. This charger completely shuts off when the red led comes on at 14.2V and doesn't come back on again until the cell voltage drops to around 13.2V. The charge you get is very deep, penetrating the plates very nicely. I don't understand. To drive a fully charged 500AH battery bank to 14.2 volts requires a charge current of 1% to 2% of the bank's capacity, 5 to 10 amps. I suspect the little 1.5 amp charger would never drive the bank up to 14.2 volts. It [the battery] will only sulfate when when the lead sulfate in suspension gets saturated enough [that] the ions form crystals that gravity falls out into the bottom. Sulfation which drops to the bottom of the battery case does not decrease battery capacity. There's space at the bottom of the battery for just that reason. The battery's service life is decreased; ultimately enough crud will drop to the bottom of the battery to short it out. Large lead sulfate crystals *which are imbedded in the plates* do decrease capacity; they act like insulators and remove that portion of the plate from service. It's sulfated plates, not lead sulfate sittin' in the bottom of the battery, which reduce capacity. But that's not my question, which is, would slowly charging an 80% discharged battery for 20 days (which means the battery would be 40% or more discharged for 10 days) result in sulfation problems? If you're charging at an average current of 1.5A and the loads are averaging 2A, that isn't going to work and you'll arrive at the boat with dead batteries, ruined. Agree with that. But I'm not certain that a 1.5 amp charger will fully charge a 500AH bank. Have you actually done that? 1.5 amp charger charging a 500AH bank or larger. I'm guessing a 500AH bank would need at least a 5 amp charger to bring it up to 14.2 volts and a fully charged state. A 1.5 amp charger might bring it up to something like 80% charged before it can't up the voltage above 13.2 volts or so, and just floats the partially charged bank. Could be wrong though, anybody wanna chime in here with firsthand experience? I do agree a 1.5 amp charger will float a fully charged 500AH bank, that's 36 amps a day, more than the natural discharge loss of the bank. But will it charge it up from a deeply discharged state? |
#10
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I'd like to hear an advice on the following related question.
My summer was plagued by continuous low charged batteries due to the fact that I was most of the time sailing (literally: wind-sailing). Every time I would turn on the engine the alternator would provide only 20A and, with a 400Ah bank, that would mean ages of noise and vibration. The alternator itself is a good Motorola NGM 14V 75A and the engine is a even better Perkins 4.108. Both would be able to deliver much more than the scanty 20A. Notice that the Motorola has the regulator enclosed and I do not know if a "smart" regulator would fit. I understand that there should be a way to cheat the regulator and force a higher charge for at least some reasonable time. Anybody knows how? Notice that the noise and vibration would surely prevent me from forgetting the "cheat" switch and overcharge. Thanx Daniel |
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