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Forum Index : Solar : Australian Standards and DIY solar install
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| Davo99 Guru  Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Is this what is required as exercising/ working them? A significant discharge Current rather than the actual level of DOD? |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Apparently so. Its like if you were confined to bed for six months, I guarantee you would not even be able to stand up, maybe even have a heart attack even trying. But if you had spent about two minutes every few days on an exercise bike you would probably be fine. A short serious occasional discharge, and a bit of occasional gassing, stirs up the electrolyte and keeps the plates clean and the battery healthy. Cheers, Tony. |
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Technophiliac Regular Member  Joined: 18/12/2020 Location: New ZealandPosts: 92 |
Makes sense for free running sulphuric acid. What about Gel cells? Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Well that sure makes things easier! Just need a couple of substantial inverters and a double element water heater!  |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Using the same silly analogy, a really deep discharge is like exercising to exhaustion. Not too bad occasionally, maybe even a good thing. But doing it all the time is not going to be so good for you long term. Cheers, Tony. |
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| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 92 |
Respectable questions in this post: They say that for LA generally. Rightly or wrongly I think about it like this: The life of a LA battery is expected to be determined by the sulfation (and probably other chemical processes) of the surfaces of the lead plate(s). When the lead plate is sufficiently masked by rubbish (retained sulfation) build up the battery will essentially fail (Assuming other reasons for failure are not present such as warped plates shorting, or loss of electrolyte...) (between writing and posting checked against https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery ) Following this logic the life of the battery is determined by the time it takes to bugger the plate surfaces. If "they" are correct the deterioration of the lead plate surfaces must be accelerated during times of discharge and depth of discharge particularly seems well acknowledged as an "accelerant" of plate degradation. Similarly each cycle chips away (more correctly masks) at the lead plate surface, again depth of discharge a significant factor in the result. If the plates are thick enough and you are up to it I speculate a battery can be restored simply by removing the lead plate surface re-exposing the raw lead for a second life.... It will then be clear whether new electrolyte is also needed, idk. Thinning the plates may well reduce safe available load as the thinner plates may well buckle more easily..... (Hmm I wonder if that could be done chemically?!) From the principles I set out the objective surely is to keep the battery charged, minimise cycles, minimise depth of cycles, use power in real time, while having a fully charged battery as much as possible "an observer" and siphon power off to various places in order of importance, (e.g. battery, fridge, hot water...) with the last place (where available) "the great battery in the sky" called the Grid (via grid tied inversion!) Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Yup ! I designed the Warpverter to run directly off the solar panels which requires a quite high voltage span, in my case up to 145 solar volts. That happens during the day with good sun and very low load, and the battery never sees discharge during the day, unless there is almost zero available solar. At night when solar voltage falls below battery voltage, only then is power drawn from the battery. So it charges during the day and discharges at night. None of this shuffling power in and out of the battery during the day, which is what happens when the inverter is connected directly to the battery. So I can allow the battery voltage to come right up almost to the gassing point during the day without any discharge whatsoever, except on really grey awful days. That will be my approach with lead acid as well. Fully agree its usually crap or sulphate on the plates, or sediment shorting between the plates that causes a flooded lead acid cell to eventually fade away and die. With sealed lead acid, its more likely to be a cell drying out from gassing. So how best to treat a lead acid battery depends very much on the battery type and usage. But flooded cells like a bit of work, a bit of gassing and temperature change keeps things stirred up and clean. A very long slow discharge, and long slow trickle charging does not really count as heavy work, even if its cycled right across the full range of voltage. Edited 2021-11-04 11:55 by Warpspeed Cheers, Tony. |
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| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 92 |
Would higher voltage / frequency "desulfation" pulses be better: https://web.archive.org/web/20070402140958/http://www.dallas.net/~jvpoll/Battery/aaPictures.html I assume this is part / a stage of the 7 stage battery chargers. Personal anecdotal observation is 7 stage battery chargers do extend car battery life. The principles seem to me to be the same. Edited 2021-11-04 12:57 by Technophiliac Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
I have never succeeded in bringing a stuffed battery back to as new condition with any type of desulphator, and I have tried a few different ones over the years. These days I just buy a new battery and be done with it. Cheers, Tony. |
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| Technophiliac Regular Member Joined: 18/12/2020 Location: New ZealandPosts: 92 |
My experience of stuffed batteries is the same. But do desulfators extend battery lives? In the absence of convincing evidence beyond my limited observation - your conclusion is pragmatic. Davo, Wellington. You can have it perfect, on time, and at the best price. Choose any two. |
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| Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138 |
Large flooded cell packs can use an air bubbler device to stir up the acid and prevent stratification, especially for low discharge and charging. See Link Cheers Mike |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
That is an interesting idea I have never heard of before Mike. An aquarium bubbler comes to mind... I think you might need to be careful not to stir up any accumulated sediment, or it may do more harm than good. Difficult to know really. One thing I have had great success with is a type of home made battery charger that keeps unused batteries alive for months or years without any sulphating. It runs from a 15v plug pack with an 18 watt tail light globe in series. Its therefore short circuit proof.... The cold resistance of the filament is about a tenth of what it is hot, so it also controls and limits charging current to a certain extent. Not really possible to overload a 15v 1 amp plug pack. And from the dull orange glow of the filament you can see exactly what its doing. But the most important feature of all, it disconnects charging when the battery reaches 14.2 volts and it stays off until the battery voltage falls all by itself back to 12.4 volts. Charging then re commences back up to 14.2 volts. It cycles on and off forever. How long it stays off is a pretty good indication of self discharge and battery health. A good battery should only cycle once every few days and recharge very quickly. A weak battery may cycle in hours or only minutes. Its great for vehicles or equipment that very rarely gets used. Had it now for about five years, its something I would never now part with. Edited 2021-11-04 15:07 by Warpspeed Cheers, Tony. |
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InPhase Senior Member  Joined: 15/12/2020 Location: United StatesPosts: 178 |
Life in the forklift keeps the cells pretty well stirred.... Maybe just put a cam on a gear box under the battery shelf and shake the hell out of the cells periodically. |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
That's actually not a bad idea. Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
These shakers/Vibrators are pretty Common. Pretty sure I have seen them cheaper on Allie or Bangood. Vibrator Motor  |
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| Godoh Guru Joined: 26/09/2020 Location: AustraliaPosts: 458 |
Hi Davo, those shakers used to be used on concrete silos to make sure the powder moved down when they were emptying the silos. I used to rewind them, they shake a real lot, depending on size they may be too powerful for batteries. It could end up shattering the plates. My BAE VRLA batteries came with graphs that showed expected lifespan of the batteries compared to depth of dishcharge. I try to make sure that mine are never below 70% charged. According to the literature I should get around 12 to 15 years out of them at that rate. On another note just wondering if anyone can look at my Transformer question and give me an idea of why my inverter is behaving as it is. Thanks Pete |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Hey Pete, You posted your question in the Guest Book, not on the main Forum. That is why nobody could see it. I replied in the Guest Book part of the Forum. https://www.thebackshed.com/forum/ViewTopic.php?FID=1&TID=14268 Edited 2021-11-04 17:32 by Warpspeed Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
Yeah I have seen them in 2 and 4 KW Sizes with 3 phases motors but this one is only 30/ 60W and comes with a a speed controller so the vibration could be regulated. If this idea was to be used, might be a good Idea to rubber mount the pack cause I can't see one of these little things doing much to 1100Kg of batteries sitting on concrete or wood. I would Imagine that the vibration even from a bigger one of these would be much less than the Impact of a solid Rubber Tyre Fork hitting cracks and ridges in concrete and the occasional pot hole. Probably like belting the case with a sledge. Used a 2.5T Petrol fork in the yard and the steps in different slabs of concrete could be enough to loosen one's fillings and compress your spine if you hit them straight on and not all that fast. I always understood the higher you keep them topped up the better. Tony's Inverter that runs off direct solar input so the battery capacity is never eaten into through the day sounds ideal. I suggested this to a mate who was doing a backup system for his erratic power in the country. By putting a tight threshold on the inverter he can draw off the power the panels are making through the day and run his pool pump and hot water ( at reduced input and longer hours) if there is sufficient input and the batteries are still at something like 98%. I think I'll drag out my original solar learning setup and have a play with that again and remember what I have probably forgotten. I have a controller on a Board with some switching and gauges and run an inverter off a couple of car batteries the same way. Much like Ballast rather than a reserve. I could put a Kilo of panels on it and run the outdoor Fridge and air pump for the bog tank. Won't matter if they don't run though the night, the fridge is always loaded and only opened a couple of times a day if that and the air pump shouldn't need to be run at night either. I did learn a lot from that and enjoyed playing with it. Going with Tony's other idea, I could also put a charger on the batteries which was set at a slightly lower top voltage. This would supply power all the time ( to the fridge anyway) and only kick in when the battery voltage dropped. Through he day the solar would provide the power at a higher level than the charge so it would do nothing till the voltage fell. I used this idea before with a heater for my seedling raising and it worked perfectly. Might be that keeping the fork batteries pretty well topped up and hitting them with a High current discharge and maybe Recharge ( and possibly up to a bit of gassing) occasionally may be the ticket. Perhaps their easy solar life may be a bit too easy for them without giving them a bit of what for on occasion.  |
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| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
With regard to stirring the battery juices. You probably don't want to shake it so hard the thing is a blur...... But mounting the 1,100Kg (or whatever it is) on some car coil springs, it should bounce and rock fairly easily at a nice gentle pace. It would probably take very little to get it moving and even less to keep it going. A fairly gentle sloshing around, like a fork lift being used, might not be too difficult to arrange. Cheers, Tony. |
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| Davo99 Guru Joined: 03/06/2019 Location: AustraliaPosts: 1578 |
I didn't know there was a Guest book and when I go to the forum index page I still can't see anything listed. |
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