Author Topic: Getting rid of lead-acid battery electrolite (Read 9034 times)

JW · « **on:** July 18, 2008, 10:50:28 PM »

I have several batteries that I wish to refurbish.

Since one or more of, each of the cells in each battery, has run low, with regards to electrolite levels. I will add some distilled water to bring them up. But also I plan to add a drop or so of phosphoric acid to each of the cells, then recharge, drain and refill with fresh electrolite. I supect the batterys are highly sulfated.

[http://www.aba-brno.cz/aba2003/abstracts/03-Rus.pdf]

I will have to wash the batterys at some point. My question is, what to do with, the spent electolite fluids. I cannot just dump them.

http://hawaii.gov/health/environmental/waste/sw/pdf/oldcbats.pdf

Has anyone experimented with chelating for the lead? Such as an alkaline sugar complex? to neutralize/lock-up the lead toxins I mean. Just curious...

Here are some additional links

http://www.patentstorm.us/patents/5945236/description.html

http://www.fieldlines.com/story/2006/10/6/20628/5315

Im going to go the phosphoric acid route versa the ETDA. I figure that I can recharge the plates(dry-charge) using that additive(phosphoric acid), before dumping waste that has to be re-treated, with a cation complex to lock-up potental re-active lead. Then once the battery/plates are washed, fill again with [pure]fresh sulfuric acid electrolite. Its a different way to de-sulfate, but Im concerned about potental waste. But performance after the process, should be exceptional(like new). Before I get into this too far, I want to know what to do about the spent electrolite waste. Doe anyone have any ideas?

JW

spinningmagnets · « **Reply #1 on:** July 18, 2008, 05:21:15 PM »

Litmus paper is very cheap and easy to get, it will give you a rough indication of the Ph of the waste.

I "think" fresh elctrolyte is about 10% sulfuric acid in 90% water. With the sulfates embedded to the plates, the sulfuric acid portion will be very weak.

I don't recommend performing any chemical reactions in your back yard, but if you're going to do something anyways...

Wear clothes you don't care about and will not wash ever (will contaminate washing machine). Nitrile gloves and goggles, plus a face shield (may sound like overkill, but my mom has one eye, so...). Keep a 5-gallon bucket of water handy for dunking and flushing.

Slowly add the electrolyte to a bucket of water to dilute it (never pour water into acid). Then you can slowly add a watery solution with some bicarbonate of soda in it).

Wait for fizzing to stop, and occasionally test for Ph. Continue until it reads neutral (7.0, PS, if Coca-Cola syrup was 1/10th a point more acidic, it would have to be transported as a hazardous material)

I am not familiar with phosphoric acid, except I've heard its very nasty. Please post your results and any emergency room details, if applicable.

vawtman · « **Reply #2 on:** July 18, 2008, 05:32:50 PM »

Hi JW

Most drain openers are more toxic.Just flush the acid with lots of water.

Mark

JW · « **Reply #3 on:** July 18, 2008, 06:50:49 PM »

Thanks for the reply's guys.

SpinningMagnets:

I can assure you that im no novice when it comes to handling chemicals. Now, what your describing sounds much more like nitric acid ACS, or chromic-sulfuric acid. Ive gotten sulfuric acid (acs) on my bare hands before, its not really a big deal, phosphoric acid is even less of a worry to me. Actually HCI has very toxic vapor's when combined with water. So dont inhale them.

Thanks Mark,

I was more concerned about possible re-active lead content. I know that dilution before dumping helps alot. Could go a long way to lock things up.

As I mentioned, forming a black dirt/sludge in the bottom of such a solution, that could be mechanically filtered out, would make me feel better. Since I dont want there to 'even' be a chance that a lead-sulfied or whatever else, getting into the watershed.

JW

vawtman · « **Reply #4 on:** July 18, 2008, 06:59:31 PM »

Hmmm, Now i'm worried about all the sinkers i lost in the river fishin over the years.

kiddin ya bud.

JW · « **Reply #5 on:** July 18, 2008, 07:41:35 PM »

lol,

This is my point. as long as there lead-metal its shouldnt be a big deal.

JW

DamonHD · « **Reply #6 on:** July 19, 2008, 02:07:13 AM »

I really don't think that you should be casually disposing of lead metal/sludge nor lead metal compounds (eg in dilute electrolyte solution).

Neutralising the solution is a kindness, but if you let those lead compounds get into a water course or the water table you are likely to poison many things.

Please take the whole lot to a licensed recycler/tip to deal with properly.

Rgds

Damon

bob g · « **Reply #7 on:** July 19, 2008, 09:10:35 AM »

i am strongly suspicious of the process to start with, let alone concerns with

proper disposal of toxic byproducts.

first of all, if the plates are heavily sulfated, flushing and doing any sort of treatment and then refilling with new electrolyte is going to be problematic.

the reason is

if you are able to break down the crystallized sulfation you will return the acid locked up to the electrolyte with the result being a much higher specific gravity

and rapid destruction of the plates.

personally i believe you would be far better served to follow the procedures that have been around for nearly as long as there have been lead acid batteries,

i know that it is not as sexy or new age, but it has been proven to work in cases where there is something of a battery to start with.

in any case, whatever sludge you end up with, please see a battery recycler first

to see if you could drop off the stuff with him. even then there are transport issues that you will have to attend to. legally speaking some things require special permits and placards to transport legally.

its one thing to transport your dead battery to a recycle center, but quite another to legally transport the lead based sludge in my opinion.

bob g

Jeff · « **Reply #8 on:** July 19, 2008, 09:30:57 AM »

Check with your local auto parts store. I checked with one here in no-where's-ville, and they'll take used electrolyte. Having my own well here, I'm VERY concious of anything I put into my own sewer that ends up in my water table!

JW · « **Reply #9 on:** July 19, 2008, 02:38:22 PM »

Thanks all for the comments.

Rural McG,

I think yours(comment) is the best with regards to getting rid of used electrolite. Id like to be able to 'flush' the electrolite in my batterys. Im only working with 2 batterys and they are a top of the line type. So the matting inbetween the plates is in exceptional condition. These batt's are about 5 years old, seem's to me I paid over $250 for each. If I can rebuild them, Id like to. The big prolem was what to do about any spent or flushing electrolite. Containment is not a problem at all, I have a nice polyurethane high wall tray to spill the batterys into. Just didnt know what to do with the stuff after flushing the batts. Thanks Rural..

OK,

Now ive started the process, and am not going to have any waste for this first phase. I have found 5 of the 6 cells in each batt were low. I have just added distilled water to them. So far the specific gravity meter will not even register low charge.

Rather than rush into adding 1ml of phosphoric acid to each full cell. I will add some sulfuric acid and try to get the SG meter to register on its lowest point of its scale.

I use pipettes to add acid(acs) to the battery. I will only use the phos acid if the battery does not respond to a more conventional treatment.

So after I reach the SG with the sulfuric, I will set the batts off to charge with a wall transformer, then check the SG after that. If things go well, I wont mess with the phos acid additive, also im 'not' using ETDA additive.

At this point the only thing that I plan to add is ACS sulfuric in very small quantitys such as 1 or 2 ml. But this will occur before any charging. I plan on letting the batts sit for a day or so after adding anything, then charge.

JW

JW · « **Reply #10 on:** July 19, 2008, 03:38:26 PM »

"in any case, whatever sludge you end up with, please see a battery recycler first

to see if you could drop off the stuff with him. even then there are transport issues that you will have to attend to. legally speaking some things require special permits and placards to transport legally.

its one thing to transport your dead battery to a recycle center, but quite another to legally transport the lead based sludge in my opinion.

-bob g"

Hi Bob,

unknow I was thinking about this a little before your post. In the end I think no matter what a techinque is, the waste should be handled responsibly. With some basic inqurys im sure the proper way to dispose of electolite will present its self readily.

By the way, my idea on chelation, would be counter-indicated since a waste-stream already exists, one would not even have to attempt to treat there own waste. Besides If you even went that far, it would be very advisable, to add 33%formaldehyde(by volume) to the sugar thats intended to precipitate the lead-metal, since it contians 75% methyl-alcohol. Any type of cation solution that contains alcohol goes along way to stabilize the resulting sludge. Its just a brain-fart I had.

Its quite another thing to just get rid of the stuff thru proper channels, then to attempt to treat it. I just know for a fact, electrolite from a lead-acid battery is different that plain old sulfuric acid. I would never dump such a thing. But In short I do agree. Even if the whole project fails, I can drop off the battery at a recycler. Its the additional potental waste stream from the spent electrolite that is what I had questions about. Considering one can get rid of that too, I say whats the harm in trying to bring a battery back, if the process can be accommodated responsibly.

JW

JW · « **Reply #11 on:** July 19, 2008, 05:39:29 PM »

Progress report,

OK,

I have added only distilled water at this point. I have filled all the cells in both batteries to there top level. Id did this like 4 hours ago, the float voltages look more stable and promising. Although I have not yet connected any charging leads. They were both over 12v before, and have droped about a volt or so, since filling with distilled water. Actually some of the cell's electrolite 'is' registering on the SG meter,now, at least at the lower end of the scale. Im going to wait 24hrs before doing anything else. So tomorrow a may attempt to adjust the SG by adding (acs)sulfuric acid, to get all the cells to at least register on the lower end of the SG meter before charging. Im figuring 24hrs after any adjustment, of the electrolite, before the charging process is started. Then from there, load tests. I have a good snap-on load tester. When these batterys were new, they made over 1000cca for 15 seconds with a full charge. They wouldnt even make 10amps(cca) when I started this, after any amount of charging, they just boiled over. I have the amp-hour capacity rating[for these] somewhere around here, cant find it just yet, but for me, a load test will be good enough to show results.

JW

JW · « **Reply #12 on:** July 19, 2008, 07:15:03 PM »

OK, ok

I got a little excited earlier, and decided to add some sulfuric to one cell in each battery.

So I got the pipette out and added some.

Im only adding 2.5 ml of sulfuric acid (acs), to each of the cells.

Before adding any sulfuric, this was the reading on the SG meter, im hoping by tomorrow to get a better state of charge, I expect to still be in the low range. As I have stated before, I have not charged the batterys in anyway, since adding distilled water. So if the reading comes up at all, with the addition of acid, I will feel better about charging. Also I intend on taking SG readings after charging. I do not intend on adding anymore sulf acid, if the reading on the SG meter go's up, after charging. You could say I only intend on adding before a charge. If the battery does not come up, I will go the phos acid route. Well see, should be interesting. My gut feeling is that these batts will come back 'up' without the phos acid additive, since there in such good shape.

JW

JW · « **Reply #13 on:** July 20, 2008, 11:45:48 AM »

So far so good.

This morning I checked the specific gravity(SG) of the cells. The ones that I added 1ml 'acs sulfuric acid' too, the readings were only marginally better or un-changed.

I think adding the distilled water has made the most difference so far. The reason im adding any sulfuric is because thru over-charging I boiled out 5 of the cells in each battery. Im thinking that since some of the electrolite was forced out of the batterys, its a good idea to freshin the electrolite.

Since adding the 1ml of sulfuric does not appear to hurt the battery any, I added 3.0ml total sulfuric, to each of the cells in both batterys, this morning.

I have set one of the batterys on the charger(will show picture later) and its taking a charge well.

When I first had problems with these batterys, was after they were over-charged. I would try to charge them and the float voltage would rise to 17 volts.

As far as I knew these were sealed batterys, they are the 'AGM' type or 'VRLA'. The other day while charging the battery I smelled rotton eggs in the air. This is when my break-thru came and I found the cell caps. There is this cover over them, so you cant see them without removing it.

Since I can add water to these, I think they will be ok. The matting inbetween the plates has good integrity, there taking a good charge, as long as the float voltage stays below 14v they wont boil over, seems I can treat them as flooded lead-acid type for the most part.

So far ive spent 99 cents for the distilled water, had every thing else laying around. So if these batterys take a decent charge with what ive done so far, im going to leave them alone and just use them. Although I am curious as to what the SG readings will be like once there fully charged. I figure it will take about 24 hours to get both batterys charged up.

JW

Capt Slog · « **Reply #14 on:** July 21, 2008, 02:12:23 AM »

I "think" fresh elctrolyte is about 10% sulfuric acid in 90% water.

Nope.

It's stronger than that. I guessed at around 40% when I first read your post, but a quick look-up gives it around 30%.

As a chemistry technician I once made-up some from conc. sulphuric, it hissed and spat and got quite warm, and I was glad when I'd finished!

.

JW · « **Reply #15 on:** July 21, 2008, 01:58:29 PM »

Hi Capt,

I was figuring about 40%, but 30% sounds more reasonable. I have added 5ml total acs sulfuric to each of the cells in one of the batterys, the other has a total of 3ml added per cell. I have no idea what the volume capacity is, for each cell im figuring 16fl ounces. With what ive added so far I dont think ive even come close to adding 10%. Im doing my best to recover the original electrolite.

The greatest quantity of anything that ive added is distilled water, both batterys together consumed nearly a half gallon of it. Thery were pretty low, infact only one cell in each battery even had electrolite over the plates.

For what its worth, the specific gravity has raised, after a charging cycle. this battery was topped off with distilled, then 3ml per cell was added. After a charge of about 10hrs, it hit 14.10 volts and vented a little. I then checked specific gravity in the cells and it rasied a little. there are some new pics at the bottom of the page.

JW

JW · « **Reply #16 on:** July 21, 2008, 02:14:20 PM »

Hi all,

Heres a picture of my charging station.

After charging about 10 hours or so I checked the SG

I check the SG just after a charge cycle.

The SG has increased noticably. Im load testing with a 75watt light bulb, and the voltage readings verify atleast that much charge. My next step is to get the SG up into the silver range there.

I added 2 additional millileters of sulfuric to one of the batterys, after charging, giving it a total of 5ml total added for each cell, with which both were topped off with distilled water at the beginning of the process. The other has 3ml total added per cell.

Im now going to go thru a cycle of charging, measuring SG, and discharging. well see what happens with these. As of this point I do consider the batterys 'usable' again for the application. I just want to see the SG increase a little more, before I start using them again.

JW

JW · « **Reply #17 on:** July 21, 2008, 04:46:19 PM »

Ok,

I have seen a pattern here that seems to be working. I started out with these two batterys. One of them has always seemed to have had better performace ratings than the other. I attribute this to overcharging the one with lower performance when I first got it.

The largest difference between the two is the charge rate. In otherwords, the battery that take's a charge at 12.65volts for the longest amount of time, such as 3 hours, gennerally will perform the best, under a load test.

Theres always been a difference between to the two, in respect to charging rate and load test.

The battery that has only 3ml total added is the best battery of the two. I isolated it the other day with my load tests, before adding more sulfuric to the other battery, also charging rate was much slower(which is good) with that one(3ml total per cell).

As I stated before, these(both) batterys, are in working condition.

As I entered the next cycle, with regards to charging rate, one clearly did better than the other. Also, once charged, each battery, would reach a float voltage of 14v within a half an hour, upon a full charge. So, no matter what, once charged, I can't pump anymore charge into each battery(it hits 14v and I have to stop). At this point, is when I check SG and add acs sulfuric, if any is added. The one that has had a total of 5ml for each cell, is trending toward better performance(its taking a charge longer than before), but the load test is un-conclusive at this point.

So I add sulfuric in 2ml quantitys for each cell of a given battery, before I discharge it, to at or under 11 volts. I have noticed this practice will increase battery charge time, giving better load test results. I will post the next set of SG readings as I get them. Also as I load test, I stop at progressively higher voltages, such as 11.75v when im done, with several cycles(this takes over 48 hours). I see no reason to discharge the 'good' one to lower than this. The other is catching up each time I add the sulfuric to it.

I add small quantitys of acs sulfuric(such as 2ml at a time for all the cells) just after I measure SG then go into a discharge cycle. The batt that has only 3ml total added per cell is the best performance wise, for now, its my hope the other(with 5ml total added) will surpass it performance. The next time I check SG, I plan to add 2ml more of the sulfuric, to that one, bringing its total per cell added to 7ml. The control battery will still only have 3ml total added and its already, clearly, the most powerful of the two. Well see.

JW

JW · « **Reply #18 on:** July 24, 2008, 12:49:00 PM »

Ok,

Things are definitly looking up.

This is the same cell from the pic's before. All the pic's with the SG meter are from the same cell, in the same battery. I left my SG meter outside and the sun got to it a little. Thats why it looks faded now.

This cell has had 5ml sulfuric added total for this reading, after 2 discharge/recharge cycles. I measure the specific gravity after charging the batt to 14volts each time.

I will give more details in the next post. Theres alot going on with the different cells,(in each battery) some have lower SG than others. It will take till atleast mid next week for me to make some conclusions. The batts are definitly back to life. This is turning out well, things look good.

JW

JW · « **Reply #19 on:** July 24, 2008, 04:45:36 PM »

I see a pattern/trend as to adding the acs sulfuric.

When I first started to work with these batterys, they were boiled out. So I used distilled water, to top off all the cells in each battery.

I then charged the battery's and the SG readings were low. So at 14volts, for the batt, the SG readings were low...

By adding ACS/REAGENT Sulfuric acid in 2ml quantitys at a time, to a given cell in a battery, once charged to 14 volts, it has been determined to increase re-charge time, after discharge cycle, in the following cycle, which is good.

In otherwords, Once I had a battery fully charged, I can add sulfuric, then discharge, to a given voltage, and the time for re-charge would be extended by the adjustment to the electrolite.

Im using a slow-charge method, so im not using a battery charger or pulse charger. Its a 'wallwort', wall transformer type. Rated at 12vdc 700ma class 2 transformer. Open circuit voltage is 17volts.

Anyhow, I get too this point, that I cannot charge the battery's anymore with it at 14vdc, they start to boil over. I take an SG reading, add sulfuric, then discharge, it takes longer to re-charge than before. So, I have been pretty impressed by the increase in charging rates. Battery discharge performace/capacity in amp-hours, has reflected this...

As I said before, it will take sometime to make a conclusion. But anyone can see what im getting at.

At first, I was worried that I would render the original electrolite useless, Fix the plates somehow, then have to re-fill with standard electrolite, dumping the old electrolite, to get a useable battery.

But now I see, that I can add distilled water and sulfuric ACS, to the original electrolite and get things working, without flushing any electrolite from the project battery's. But the battery's have to be in good shape, with regards to a visual inspection of the plates in each cell.

Providing that the batt's are not in hopeless shape, with regards to the mat inbetween the plates. I have seen many batt's that I would not even try this on, since the mat is pushed out or comprimised inbetween the plates.

These (agm) batt's are in really good shape. So its worth it, to try this.

JW

JW · « **Reply #20 on:** July 25, 2008, 01:47:41 PM »

Im very pleased with the results so far.

I checked the specific gravity of the cells in this battery today, all cells are now in the silver or 'fair' range. Although they are at the bottom of the this range, the readings are significantly improved. In this battery there were 5 boiled out cells. The one cell that was in the fair range yesterday, is now in the bottom of the blue range or 'good' according to the scale on the SG meter. Charge time has increased correspondingly.

After the readings yesterday I added 4ml sulfuric, then discharged/re-charged, to get my SG readings today. Today, I again added, 4ml sulfuric to the the cells, bringing the total added to 13ml for 5 of the cells and 9ml total to the one cell that came around first.

The other battery has only had a total of 3ml added to each cell, Ive not measured the SG of its cells yet. But its charge rate is normal. This means that it takes a full 48 hours to recharge from discharging to 11.75 volts. In this amount of time the voltage never exceeded 13.75 volts.

Im not quite sure, if the difference between the two, is the condition of the plates or whatever. But the weaker of the two, is gaining capacity, as a result of adding the sulfuric. I kind of do things one step at a time, if it needs it, kind of thing. Since the performance of the one, is at what I consider good, I dont just arbitrarily add additional sulfuric. I wait and see how things are going, then make a decision based on that. This is why I never added anything but distilled water and sulfuric (acs) to these batts.

Also it has been advantageous to restore the original electrolite. I see no problem matching the capacity of both batterys, and getting SG readings in the blue or 'good' range, using this method.

Im going to use the batts tomorrow night, to power the 115 watt lighting system on my boat, for sighting some lobster on the flats. I will use the system for about 6 hours as we will use them for some night fishing too.(hopefully the water will be calm) Lobster season opens in august. I do have an 6amp charging alt, on the motor to keep things going. Before I boiled these out, 6 hours run time, was no problem for these batts in parralel with the engine not running.

Before I was thinking, of trashing these batterys, but it would cost $500.00 to replace them, so im very pleased with all this progress. They have a production date of 08/2002. More SG readings to come next week. At that point I will be about done with this process and batts should be in good shape again.

JW

JW · « **Reply #21 on:** July 27, 2008, 02:39:54 PM »

Im at an interesting point with these batterys.

I have conducted load tests on both batterys. The batt I only added 3ml sulfuric to each of its cells, after topping off with distilled water, has just more than 2/3rds the capacity of the other.

The other batt also was topped off with distilled water, then an average total of 12ml sulfuric total was added to each of its cells. This is the one that has just less than a 1/3rd storage capacity of the other.

I have been thru about 4 charge/discharge cycles and the batts are performing consistantly as far as I can tell.

I suspect at this point the one with less capacity is sulfated. Aparently the other was not, and nothing that I have done with the sulfuric has helped this condition. The one that came back up to good capacity, responded well to the load and charging tests right from the start. The other, that had more sulfuric added, did not.

Im reasonably satisfied, that the one with the third storage capacity is not going to improve, by adding more sulfuric, and most likely should be replaced. I have found a decent 65 amphour batt for 79 bucks. I feel the will be the ultimate solution. The fact that I treated the batterys somewhat conventionally, is probably why the one came back up, since it really was not that damaged/sulfated. The other is a different story.

Just out of curiousity, Im going to add the phos acid, to the weak batt, in 1ml quantity to each cell, let it sit for a day or two then recharge and see what happens. I dont expect much, as the main difference between the two batts is that the weaker one, will boilover within 8 hours of charging(@700ma) from discharge. The stronger of the two takes about 48ours of charging at 700ma before it will start to boil over. I had even tried charging the weaker with a 400ma wall transformer, but it still would boilover in about 10 hours. The batt does work, but its performance is unsatisfactory.

JW

JW · « **Reply #22 on:** July 28, 2008, 03:39:53 PM »

Alright,

Yesterday, I added 2ml of the phos acid acs to each of the cells of the weaker batt. Of which I have mostly given up on at this point.

My biggest problem with this batt is that it will boilover before it can take a full charge. The other batt does not do this, so for the mostpart, I have left it out of any drastic moves.

Also, something that has me scratching my head, is the fact that the battery electrolite did not turn black, with the addition of phosphoric acid, as the artical about adding this said it would.

Today, I said what the hell and added an additional 8ml of phos acid to each cell, bringing the total of phos acid added total to 10ml per cell. Its important to note this was the same batt that had a total of 12ml(avg) sulfuric added to each of its cells. The other batt, thats working good, only got 3ml total sulfuric added per cell, for comparison.

Im now in the process of discharging this battery(weaker) to less than 6volts, in the hope that when I begin to recharge it, it will take more time to recharge than a mere 8 hours. Well see. My rational for this, is a rumor I heard years ago, that, if a lead acid battery, was completely discharged(to 0v), you could reverse the polarity of it, by charging it backwards :ie negative to positive on the charger, etc.

As you can tell, I have already decided to replace this battery But I am going to recharge it with proper polarity. Its become a science project at this time

JW

JW · « **Reply #23 on:** July 28, 2008, 04:14:58 PM »

One thing that has always puzzled me about the difference between the two batterys, as alwasys shown nearing the end of a load test.

For example the good batt, never discharges below 11 volts, but has remarkable capacity from the 12 volt to 11 volt range.

The worst of the two, will drop to 9.5 volts, then have good discharge capacity.

The load I use is a 75 watt 12v bulb.

The batt that goes from 12v to 11v with the 75watt bulb as a draw, will do this over a period of about 4 hours.

The other, will slowly drop to 11v within an hour with this same load, then quicky drop to 9.6v from that point, then stabilize. Obviously the lamp is not as bright but it is still illuminated. This is the usual point, I will shake my head in disapointment, and put it on the charger. I suspect it will take about 4 hours to get the batt volt down a volt with this load.

I plan to discharge it to 6 volts. Will let you know how long this actually took next time. From then, its a recharge to see what happened. If charging time decreases, or stays the same(8 hours versa 48 hours for the good batt). I will not be impressed.

JW

JW · « **Reply #24 on:** July 28, 2008, 07:44:43 PM »

OK,

so its been like 10 minutes since the batt under discharge hit 5.55v. I then disconnected the load, let it sit for a few, then hooked up the 12v@400ma charger, the voltage has seemed to level off at about 9.28v after about five minutes. If the voltage of the batt has not exceeded 12v in 12 hours. I will be impressed. However if this thing is boiling over like it always does with an overnight charge, well, then. Its shot... Let ya'all know tommorow.

JW

commanda · « **Reply #25 on:** July 29, 2008, 02:09:09 AM »

I think you'll find those batteries are normal wet-cell, not VRLA (valve regulated lead acid). VRLA batteries usually have a rubber cap over the inlet, which opens when the internal pressure rises to a certain level above ambient. Also, they don't have visible fluid over the plates, and it is impossible to take an SG reading.

Amanda

JW · « **Reply #26 on:** July 29, 2008, 01:30:53 PM »

Hi Amanda,

Here's a picture of the caps on this battery, they do seem to have a type of valve built into them, then some type of diffusion membrane, on the other side of it.

Anyhow, the batt that I discharged down to 5.55v has been charging over 17hours, @400ma at 12 volts, is doing quite well. If the thing takes a charge for 48 hours, like it might, the capacity should be good. Trust me Im surprised...

JW

JW · « **Reply #27 on:** July 29, 2008, 01:45:25 PM »

Here's a veiw of the top of the cells. There is about a 1/2 inch of electrolite over the top of the plates, to reach the 'low level' indicator under the cap. This is enough fluid to take an SG reading. They are the flooded type of Lead Acid battery as best I can tell. The caps do make them VRLA but they are -Advanced Glass Mat or AGM Lead Acid type.

JW

JW · « **Reply #28 on:** July 30, 2008, 04:00:04 PM »

The addition of Phosphoric acid was not good...

Although it did keep the battery from overcharging over a time-span of 36 hours. Upon load testing, it was determined, the load capacity that the batt had, was greatly diminished. Dont add it, its not good for battery performance.

Anyhow, im looking to buy a new set, since the usable battery has a crack and leaks electrolite. Oh well, I will keep these around, atleast for there trade in value, when I get some new batts.

JW

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Author Topic: Getting rid of lead-acid battery electrolite (Read 9034 times)