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Forum Index : Other Stuff : Battery question
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| M Del Senior Member  Joined: 09/04/2012 Location: AustraliaPosts: 155 |
Hi all, I have 4 batteries hooked up to a solar panel and boosted by a charger every now and then (monthlyish)to equalise the cells. I have had them for a few years and use them for jump starting cars, camping(fridge) and 12v lighting. They are starting to do wierd things I have not seen before. I do not have access to a camera for pics. 1, three of the batteries have developed a black growth on the positive terminal, which I clean and use either vasaline or terminal protector spray, comes back in about 3 weeks. 2, one of the batteries overflowed two days ago during boost, never have any of my batteries ever done that. Mind you it was very hot 
Water levels have been maintained at the same level for the last three years, hydrometer readings have not changed 1.225 (readings taken after boost charge) and the voltage varies from 12.6v resting to 14.2v under boost. The batteries are a bit bigger than a n70 and are a starter/deep cycle cross. Any ideas? I am considering getting a new set but would like keep the cash in my pocket if possible. cheers Mark Mark |
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yahoo2 Guru  Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
My guess would be that the positive plate in your batteries is expanding from sulphate crystals pushing from inside the grid. The crystals are likely to be causing material from the lead paste lattice to shed into the electrolyte solution. Sometimes you can see a grimy dark grey scum floating on the acid in the cell, or heavy staining on the vent cap. This expansion will be bulging the top of the battery or has damaged the seal around the positive terminal. I started a topic with some photos of battery damage if you are interested. The black stuff would be the residue of lead oxide from the electrolyte solution that has wicked up the positive terminal through capillary action and evaporated the fluid. The fact that it is black and not white or light green is not a good sign. Have a close look at the terminals and the top of the batteries and find a spec sheet and see what the charging volts and SG should be. That's only my theory, any other ideas? I'm confused, no wait... maybe I'm not... |
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| M Del Senior Member Joined: 09/04/2012 Location: AustraliaPosts: 155 |
Hi Yahoo, the readings I posted are what my results have been, and they match the specs given in the manufacturer's data sheets. The batteries have performed flawlessly up to now. Looked at your pics and compared what I can see inside mine, most of my cells are good, a couple have scum etc and a few plates look warped(really clear electrolite in all but the 3 scummy cells) There is no swelling, and posts are not lifted etc. So that leaves cracked housing or pourus posts then. As well as possible sulfation. When I was on the tools I saw a lot of the white/green fuzz (posts/clamps coroded to nothing) and expanded/cracked and even exploded cells/batteries. These look nothing like that, so I will clean them, recheck levels etc and start looking for some new ones.  Hopefully these will last till June/July, then off to the battery shop.
Anyone have any preferences regarding an all round battery? I got 6 years out of the previous lot, both lots were Yuasa. On the upside this could be the impetus for the start of my off grid system, mmn. Big batteries, more panels, charger, inverter etc. Must talk to SWMBO (flowers, dinner, be nice etc) thanks Mark Mark |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
As long as your batteries will still power an acceptable load without the voltage dying and they charge nicely without the voltage shooting up quickly, there is still life left in them. A bit of mess is not the end of the world. The point where I would start to consider turfing them, is when individual cells are regularly using a lot of water from low resistance (near short circuit) or the amps needed to finish the absorption charge is starting to get excessively high. Batteries that are paralleled go downhill really quick when they get to this stage, with a clamp meter you can see the power pouring out of the good batteries into the dodgy ones. Some batteries leak fluid from new, some block the vents in the caps and build up pressure. I'm sure you will work it out. edit addendum P.S. Still a good idea to lavish some TLC on the woman in your life, even if the batteries come good  I'm confused, no wait... maybe I'm not... |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi All The following link is to a good source of battery information that is interesting reading and very useful It was written early last century but the information is still up to date foe lead acid flooded cells. All the best Bobhttp://www.gutenberg.org/files/29718/29718-h/29718-h.htm http://www.gutenberg.org/files/29718/29718-h/29718-h.htm PS Batteries cost less than a woman and are useful if looked after, they do not run around or away, and you are allowed to change them at intervals less than 70 years, but tend to be less fun most of the time, well maybee. Foolin Around |
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| M Del Senior Member Joined: 09/04/2012 Location: AustraliaPosts: 155 |
Hi Bob, thanks for the link. As you said, lots of interesting info in that. Yahoo, still going to do some more research into an off grid, then ask for permission to spend the cash. Should be able to build a good system to beat my 52 cent peak power price. So I have one last question, I know I need to get my batteries all at one time and use them together. Are there any known problems caused by starting with a minimum number of panels and top up charging off peak (13 cents) from the grid till I buy the full number of panels and connect them? cheers Mark Mark |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
HI Mark There a lot of different opinions regarding off grid solar panels and their connection, but in my experience if you can run up the voltage of the cells and hold for ten minutes a day with the available panel/s your batteries will survive also better if you only expect and draw 30 % of the rated amps of your batteries they will live a lot longer, even normal car batteries will last for five years if treated properly. A good little gadget is a desulphator across your batteries as this covers a multitude of sins. At the moment I am using two old 40 watt cells to charge my 12 volt system, they are worn out really but keep it going for water pressure pump and house lights (LED) and Fluro. The heart of the system is the regulator which manages the batteries in a reasonable manner. in the morning it allows full PV current until the batteries reach 15.5 volts it holds at that for 10 minutes as an equalisation charge then goes into PWM mode for the rest of the day and floats at 14 volts, these settings are built in and not user adjustable, but for a few dollars extra now they have a programmable unit, that has the float and equalisation voltage adjustable, I have ordered one as I want to use 16 volts as my equalisation voltage. About $30 bucks on fleabay You could use a charger to maintain your batteries but most chargers do not have useful regulation unless you get a very expensive one, the problem is if the voltage is not high enough to equalise the cells will slowly die by sulphation unless fitted with a desulphator. If it is to high it will boil out the electrolyte and damage the cells unless closely monitored, I have cooked a few that way myself by being distracted and forgetting only to come back later to find it has damaged the battery. You can start with one or two panels as long as you do not expect more than they can give and 70 % of battery capacity eg. a 100 AH battery delivering 30 AH. You can not run a cell to its full rated capacity and expect it to last for long, as with all rules there are exceptions such as large deep cycle lead acid cells, NIFE cells and Lipo cells, the proper deep cycle lead acid can go to 70 % discharge and if properly cycled will stand the strain. Nife cells in my experience will go to 90 % once again if properly cycled, and the Lipo cells they say between 80 and 95 %, I have not run any myself but my friends that have some, say the cells are always out of balance across the cells and that causes cells that die, makes me think that they should be limited to a more sensible max discharge. Hope that is some help. All the best Bob Foolin Around |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
yes, no, maybe. Jeez louize, this is a tough question, give me a few days to write something, I can maybe describe how to set up a charger. What Bob is saying is spot on Mains is THE best way to charge batteries. Mains battery chargers can be the sh*ttiest bit of kit known to man. Give someone with a little knowledge an adjustable mains charger and they will stuff a set of batteries in no time flat. There is the dilemma. The advertising will lead you to believe that charger A with its 11 stages is better than charger B with 7 stages. The real issue is deciding when the batteries are fully charged and switching from absorption to float, almost every charger is the same underneath, as the charging amps reduce, they switch to float at a set amperage. The trick is choosing a charger to match this point to the batteries charging end point. The short answer is this will be around 1-1.5% of a new banks Ah capacity. Long answer depends on how the batteries are cycled and is very complex. There is another question that you are not asking. Is this my best option? I honestly don't think it is. Can you really buy power at 13 cents to charge batteries? Where I am, I would have to apply in writing for J tariff rates for, say...charging an electric car, which is entirely within the spirit of the the legislation but I doubt there have been any applications approved. I would be looking at it the other way around Step 1: grid-connect solar, taking full advantage of the govt incentive before july2013 for the solar certificates value, if you are in SA you get the extra feed in tariff as well. Step 2: couple years later replace the ...ahem..."faulty" inverter with an equivalent sized hybrid inverter/charger and batteries. my previous post on this! Do a bit of PROPER research, you will be surprised at how small the upfront cost can be and how much money you will save longterm. A couple of links about where things are heading. why generators are terrified of solar hybrid solar how to kiss the grid goodbye I'm confused, no wait... maybe I'm not... |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Be aware that the price of STC's have dropped $1 to $29.50 in the last few weeks and the large electricity generators would be very happy if the price plunged over the next few months, it would stop a lot of panels going onto houses. However, if you are lucky enough to be cashed up you can hang onto them and cash them in later. I'm confused, no wait... maybe I'm not... |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Mark One thing you could try to use a normal battery charger is to modify its output by feeding into a large capacitor bank of electrolytic s then make a crude choke with a handful of Chinese welding rods and wind 150 turns of 2.4 mm copper wire around it then another few caps and feed that into a solar regulator to handle the battery management, a bit crude but it works. It would cost a few bucks but is better than damaging your batteries. Yahoo has some good suggestions re the solar panels. All the best Bob Foolin Around |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Hi Mark, I think I am going to have to admit defeat on this one. I was hoping I could do a little guide for charging larger banks from the mains but I have run into a few brick walls. I cant put specific info up without quoting the source and I have been unable to check this because so many of the best websites and links have been removed from the web in the last 12 months. Pity! The only way I can think of around this is to pretend to install a make believe 1000 Ah battery bank and work through some of the issues that need to be kept in mind on the way. yahoo I'm confused, no wait... maybe I'm not... |
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| M Del Senior Member Joined: 09/04/2012 Location: AustraliaPosts: 155 |
Hi all Update on my batteries, one of them had a high decibel event this morning . Wife is not impressed Also had to change both car batteries last week not a good time battery wise for me.
I can now see inside it and will get rid of the other two that have been giving trouble. It seems that the cell joiners are pressed, not soldered or bolted and worked loose to the point where a spark happened. No camera at the moment so no pictures. End result is plastic, acid and some lead plate bits everywhere in my battery room/box. So time for some cleaning etc and definitely some new batteries. Main question, what batteries can be suggested? I am thinking of getting some Trojan T105s or equivalent till I set up a full system. My panel system is 24v so I would need four of them. The batteries supply power for lights and a stereo in my shed with occasional jump start duties. Any other suggestions? cheers Mark Mark |
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