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Forum Index : Other Stuff : Battery Rescue?
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| VK4AYQ Guru  Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi marcus It is correct that the chemical reaction works better at above 25 C so you will have a slower reaction time at your temperatures, depending on how many amps you are putting in to the batteries you will get some warming but I think not enough to make a big difference, a trip to the local charity disposal store, and a look for an old doona and electric blanket may be in order. Any electrochemical activity between the plates will cause slight warming of the cell as the gas bubbles are escaping this gentle reaction helps the desulphation process as long as it is not violent boiling as a lot of people think is necessary. When the battery is taken of charge the slight cooling of the cell pack causes a lowering of the internal pressure in the cell and gives the effect you mention, this effect is used to re capture some of the moisture that escapes from the cell into the trough where the rubber caps live, if you look into the rubber cap you will find small grooves in their internal sides designed to suck any available moisture back into the cell. Over time the gaseous part of the bubbling does escape to the atmosphere being H and O and that is how a sealed battery slowly dies or quickly dies with overcharging as the H2O is not replaced. I have found that a little to much water is not to harmful to the cell as it gives a bit of a safety margin, and considering that the cell was in a less than ideal state by being dehydrated the worst it can do is to lower the SG a little for a while, if it helps to recover the battery to a useful state it is a small price to pay. All the best Bob Foolin Around |
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| mab1 Senior Member  Joined: 10/02/2015 Location: United KingdomPosts: 209 |
OK then I may have to bring 'em indoors - or keep desulfating through the summer. Actually I have the main battery indoors to protect it from thermal extremes but when I thought I'd be having a lot of gassing from the recovering cells I decided to put them out in the shed. I guess I'll have to keep an eye on the cells I've topped up as some do seem to have soaked up the water and look dry again. going off topic again in regard to my setup - in case you're interested :) : I did manage to keep my grid power use to just 100KwH per annum before I got the hydro running- with 750w of solar - LED lights, laptop for TV/internet and fridge in the summer months and 'passive refrigeration' during the winter (i.e. keep it in an old fridge outside). I got the hydro running about 16 months ago; it's been done on a shoestring budget - the genny is a capacitor excited old induction motor I got of *bay for 99p - but I did end up having to pay about £400 for the pipe :( . It's theoretically able to go up to maybe 700w+ but I'm still trying to make improvements; in fact it should be ready for 400w but I just got that ready as the water flow dropped to the point where it wont support 400w. I have to say I'm very please (or smug) about the hydro - i live in a very overcast-prone part of the world, and in midwinter when it's completely dark by 4pm the solar only makes a token contribution - but the hydro just keeps on churning it out. :) ironically I still used about 100KwH after I got the hydro running but that was partly because I expanded my consumption when the hydro came online - small freezer AND an indoor fridge (what luxury! ) and because my old inverter (APC 1400VA UPS) wouldn't run much more than a fridge & freezer, and couldn't support things like the washing machine, MIG welder or toaster - which is why I got the powerjack - but then I decided I needed more battery to support the PJ. I try not to waste any power - I dump excess into the hot water tank or storage heaters - but that's not fully automated yet: I made a simple MSW 'inverter dump load' (basically a simple push-pull inverter that regulates its input voltage rather than its output, which divert excess power into a 240v element such as the immersion/ storage heater - but it has two problems; one is it doesn't like it when the thermostat clicks off so I have to anticipate that and make sure it's connected to something with enough thermal capacity to keep going 'til I get home; the other is that it was built when I had about 750w of solar an no hydro - I now have 900w solar + hydro and I don't think it'll handle more than 800w continuous. Also I still need to automate the regulation of the hydro - at the moment I have two Variacs: one into a simple battery charger and the other into one of my thermal dump loads and I manually adjust to match requirements of the day. So I need to automate the dump loads - possibly making a controller to dump power via the powerjack (once there's enough battery to support kw loads), but also I'd like to make a 24v element for a storage heater - also need to automate the hydro regulation and battery charging. Oh and I need to improve/redesign the water pickup/strainer for the hydro - ironically the one thing that can shut the hydro down is very heavy rain as it fills the stream with crud (and sometime rolls damaging rocks). All I need is more time (and money) ! Thanks very much for your advice Bob et al |
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rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
mab1 and guys I got one of these to try for a hot water/dump load http://www.ebay.com.au/itm/24-volt-600-watt-dc-Low-Voltage-S ubmersible-Water-Heater-element-4-solar-panel-/371098088820? pt=LH_DefaultDomain_0&hash=item56672b7574 But I haven't installed it yet (need to make a hole in the hot water tank) Both my wind gennys use this company's blades They got all sorts of goodies Then I will use one of gizmo's controllers and I have a 24 volt one of these http://www.ebay.com.au/itm/6-TERMINAL-Winch-solenoid-12V-sui t-Warn-Ironman-Tigerz-ARB-TJM-T-Max-T-Max-Maco-/151264984993 ?pt=LH_DefaultDomain_15&hash=item2338187fa1 to switch it over Always Thinking |
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| mab1 Senior Member Joined: 10/02/2015 Location: United KingdomPosts: 209 |
Hi Rustyrod, I have seen 24v water heating elements, but I can't install one in my tank without draining and removing it, alas, and I would assume that as it's designed for immersion in water that it wouldn't last long if used in a storage heater (in free air). I was looking into making one from old elements or modifying a 240v one, but again, I'm not sure how to get the heat tolerance in DIY joints (unless I can mig-weld them). |
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
Nothing to do with desulfators, but mab 1 did you see this at "The Back shed" Here Folks, Meanwhile, Back on the battery bench. I have nearly finished making a "Doubler Desulfator" I am waiting for the BIG capacitors to arrive on the slow boat from china. The 3 others are still singing, another few months and - well we will see. Always Thinking |
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| mab1 Senior Member Joined: 10/02/2015 Location: United KingdomPosts: 209 |
Ah that's interesting - i'll experiment with an old element... On desulfators - well I might change my mind and make a 24v one for now - I'm struggling to find a similar set of components to make a matched pair of 12v ones without buying new parts; although I may modify the design for 24v with a higher voltage fet and using a fet driver so it doesn't generate as much heat as my existing 12v one. |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All Sorry I have been not contributing for the last few days, been busy with the mower mowing the ranch and also like an idiot got my hand into the fan on the old tractor so got a decapitated knuckle growing back on, wife said I should have put my head into the fan , it might have knocked some sense into me. I did get around to making the cables to hook up the batteries to the Inverter so that's one positive. On the dump load to hot water, an easy way is to use a couple of stainless steel plates in an insulated container with salty water and vary the immersion depth to adjust the amps absorbed, then with a copper coil in the water transfer the heat to the HWS by convection, there is generally a bung in the bottom of the HWS as a drain out, and you can pick up on this as the bottom feed and the top feed can go into the feed pipe, this saves making more holes into the cylinder, and it is adjustable by the amount of plate submersed into the salt solution. The inductors for the desulphator haven't come yet perhaps on the same slow boat from china, but I did get some nice sealed plastic boxes for $2 each, and some circuit boards for a $1 so will have to take the plunge and get started, I read an article and it said that the inductors where not critical in the circuit, so I might try some from some old power supply I have dismantled. All the best Bob Foolin Around |
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
One of the desulphators has stopped. I think the diode BY229 (6amp/100volt)that I used is open circuit. I put in a 15SQ045 (45amp/15volt) but the audio I get at the battery is very very low. I will get another By229 and see if there is any difference. I have noticed the gassing is slightly more with a good unit connected. Is it my imagination or does the audio get louder as the battery gets less sulphated? I was going to use these 15SQ045 in another unit I am making but it needs a 50SQ080 and I can't find any on Evilbay I have abandoned the 4 batteries from the 32 volt set for now until I can repair the corroded connections. EG drill 3/8 hole in them and pour lead in. I tapped one 3/8 whit-worth and made a "bolt" from a wheel weight. Seems to be working quite well. I picked up a nice deep-cycle battery two weeks ago. It won't last the weekend I was told, Tested as very weak. 2 weeks later now only weak. SG is on the edge of red/white now. Always Thinking |
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Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
Hi All, That wants to be a fast recovery diode over 6 amps continuous. Here is a image for strip board that may help some. Bob 
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
WOW THANKS, That is exactly the citcuit I am doing, except I had squashed it and turned it around as I had not seen that picture before. What is the difference between a SUPER HIGH SPEED SCHOTTKY BARRIER RECTIFIER (15SQ045)and the FAST RECOVERY DOIDE (GI826CT) or the BY229 ? Oops 15 amps/ 45 volts I got that back to front in my last post, Sorry. I have found some of the data sheets and now my eyesight has gone all fuzzy. Seriously, I simply don't understand data sheets. I can solder any parts together and hope the smoke stays in, like putting bolts in an engine and hope the parts stay in. I have never understood how someone can take a handful of bits and design a circuit, even design the "bit", increadable. I think they are the greatest. I just copy it. PS. The parts list refers to the strip board not the circuit diagram Always Thinking |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Rod I have a couple of fast recovery diodes if you cannot source one locally if you are down this way, I still haven't got my inductors and had to re order, so no progress there, lost in the mail looks like. All the best Bob Foolin Around |
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
Thanks Bob, I gotta go bush next week then I hope to get back to see you soon after that. 
I went and made a new one, since lunch. I used a IRF1404 and a 15SQ045 The big choke is 100uH The 555 is sounding fine. The diode almost melted on connection.(The smoke stayed in) In the back ground is 2 doublers, I am waiting for the caps. Always Thinking |
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| Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462 |
It looks so easy. Problems I have are: Fear of polarity mistake and mix-up of connections Does JayCar have 12V desulfator kit by any chance? If not, might have to go back on this thread to find list of components and give it a go. Should I make wrong connection it will be just confirmation of my fears. George |
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| mab1 Senior Member Joined: 10/02/2015 Location: United KingdomPosts: 209 |
Hi Rusty, The problem with Schottky barriers like the 15SQ045 is that they have relatively low reverse voltage tolerance (45v in this case) and the reverse leakage current is relatively high. They're really best used in low voltage SM power supplies (like 3.3v or 5v computer supplies) where the low forward voltage drop makes a big difference to efficiency over a normal diode (that schottky is rated Vf 0.55v at 15A where a fast diode would be ~1v). IIRC you're using them on 6v blocks so that may not be such an issue, but for a 12v desulfator I'd go for a fast recovery diode of 100v or more rather than a schottky. I think I'm using a BYW80-150 (150v. 8A) IIRC. m |
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
Hi Gorgen, Only the IC, the Diode 2, Low esr cap and the Fet are polarity sensitive. If you follow Bub73's strip board it should be easy. Take your time. I did not have this picture so I set up my own. The fet pins (if you lay it down on it's back) should be "g d s" I don't have the zener or fuse, D3 and that cap. I do not know if Jaycar have a kit. I see on forums the premade Jacar units are not so good. I have never had one. A few pages back I put up a list of parts I used from Jacar. Seems to work. But I don't have a working oscilloscope to know anything. Hi mab1, Thanks. I will compare them to the BY229. And mates - The last FET I used was a N channel MOSFET (IRF1404) not a P channel MOSFET so it WILL'NT work with out rewiring to suit. Always Thinking |
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| Bub73 Senior Member Joined: 10/12/2009 Location: United StatesPosts: 116 |
Hi rustyrod ; The zener was added to protect the 555 from over voltage; voltage will sometimes soar if a charger is applied to a sulphated battery. The junction of D3 and C6 just make a crude test point so you can monitor peak voltage with dvm or crow. The fuse just helps to limit the amount of magic smoke in case of a malfunction. Bob |
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
Great ideas. Next time the soldering iron is hot i will add these improvements. Always Thinking |
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| Georgen Guru Joined: 13/09/2011 Location: AustraliaPosts: 462 |
This yellow board on previous page looks easy, but what happens on the invisible side? Are all horizontal rows connected together? Also what red small squares mean? George |
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| rustyrod Senior Member Joined: 08/11/2014 Location: AustraliaPosts: 121 |
The red squares are the cuts in the rows on the invisible side. You can put a small wire through each red marked hole so when you turn it over you can find it. Perhaps do all the cuts first before soldering any parts. Use a 1/8 twist drill in your fingers to cut the strips. Mark each cut on top with a spirit pen and then compare to the yellow board. If you are using an old piece of strip board - polish the strips shiny before you start. The heat needed to tin a dirty board will lift the strips. WATCH OUT - there is a bunch of those red dots under the IC 555! Always Thinking |
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BobD Guru Joined: 07/12/2011 Location: AustraliaPosts: 935 |
Altronics has at least three Battery Desulfators. See their product codes M8540, M8542, M8544 |
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