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How much water should I add to old AGM battery?
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Bear in mind that AGM batteries are 99% saturated with electrolyte. They are designed to be non spill able, in the event that a case gets cracked the electrolyte is supposed to stay suspended in the matting. Adding water seems like it would dilute the electrolyte to a lower specific gravity than a fully charged battery would like to see.2.2kw Suntech mono, Classic 200, NEW Trace SW4024Comment
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Originally posted by littleharbor View PostBear in mind that AGM batteries are 99% saturated with electrolyte. They are designed to be non spill able, in the event that a case gets cracked the electrolyte is supposed to stay suspended in the matting. Adding water seems like it would dilute the electrolyte to a lower specific gravity than a fully charged battery would like to see.Comment
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Originally posted by davethedrummer View Post
That's why I decided to only add 30ml, thought that might be a similar amount that might have gassed off over the years...?SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Originally posted by inetdog View PostIdeally a Valve Regulated Lead Acid (VRLA) battery will be charged at a low enough rate that no water will be "boiled off" to a pressure greater than the operating pressure of the valve. Once you have removed (or damaged the integrity of) the valve cap or caps you no longer have VRLA. The pressure is necessary to cause catalytic re-conversion of the elemental oxygen and hydrogen back to water inside each cell.
Maybe this is an older design? Would be interesting to see if the "valves" on the new Northstar batteries are also just thin rubber caps.
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Quit kicking a dead horse and wasting our time. The batteries are Boat Anchors. Geez you do not even know VRLA = AGM. Northstar batteries are made for Telecom and completely useless for cycle service. So stop wasting our time and get rid of them at your local recycle center.MSEE, PEComment
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Originally posted by davethedrummer View PostSo one out of the 8 batteries has been revived. Charging and discharging perfectly without large voltage drops under load. Was hoping for a slightly better result but overall I'm very happy that I tried this out.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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I did ask before about NorthStar Red. There are some resellers of used NS red. Ignorant PV users beleive that the SoH of these dumped batteries is 100% cause they show them pictures like this.
Can anyone explain me how is it possible that such kind of measuring tool can show a SoH of 100%?Attached FilesComment
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Originally posted by GeorgeF View PostI did ask before about NorthStar Red. There are some resellers of used NS red. Ignorant PV users beleive that the SoH of these dumped batteries is 100% cause they show them pictures like this.
Can anyone explain me how is it possible that such kind of measuring tool can show a SoH of 100%?Comment
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Originally posted by GeorgeF View PostI did ask before about NorthStar Red. There are some resellers of used NS red. Ignorant PV users beleive that the SoH of these dumped batteries is 100% cause they show them pictures like this.
Can anyone explain me how is it possible that such kind of measuring tool can show a SoH of 100%?
Note also that knowing that the battery can deliver power in the form of some very high current for a short period of time is not necessarily an indication that it has the capacity to deliver energy in the form of watt-hours, over a longer period of time.
In short, despite what the person who tested your batteries said, they may only be able to deliver some small fraction of their original rated energy before dropping the voltage to an unusable level.
And the SOC level shown is almost certainly just an estimate based on the open circuit voltage. Not to be taken seriously.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Originally posted by GeorgeF View PostAnd,
how can such a tester defines the SoH in regard of degration, corrosion etc...???SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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Originally posted by inetdog View Post
Once you have defeated the pressure relief valves, the battery will no longer be able to recombine the hydrogen and oxygen gas produced by electrolysis during normal charging. That means that you will soon have to add water again instead of having a sealed, maintenance-free battery. The volume of electrolyte compared to capacity is far smaller than in an equivalent FLA cell.Comment
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Originally posted by davethedrummer View Post
I guess you can't really see from the pictures but the caps are made of very soft and elastic rubber that is less than 1mm thick. I seriously doubt those caps would withstand any kind of pressure. There are no valves that I can see, unless they are calling those flimsy little caps valves? Seems like a bit of a stretch of the term.
Maybe this is an older design? Would be interesting to see if the "valves" on the new Northstar batteries are also just thin rubber caps.SunnyBoy 3000 US, 18 BP Solar 175B panels.Comment
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