Charge - Discharge - CHarge - DisCharge ...
Started by Dominus · · 26 posts · last reply 25 November 2013
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#1 ·
what is that VOLTAGE?
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#2 ·
Do not drain you battery down like that, you are going to kill it very quickly!
What type of battery are you using? How many AH is it?
Generally speaking just drain it to 12v with a load that is the correct size for your battery. If you are not sure than a slower discharge with a lower load is going to be best. Follow the manufacture C20 rate.
When you charge back up you want to bring it to about 15.25v if it will go there. It may not at first. Most important is to watch it charge and it will rise slowly at first and towards the end it will top off quickly. On a normal battery the sharp increase will begin at around 13.5v and rise rapidly to 15v. Your battery may not behave this way but what you are looking for is that sharp rise and if it starts to fall back after that it is done.
Just repeat that cycle over and over but give it a rest between loads and charges or you will damage the plates. As you go through the process you will start to notice that it takes a little longer to charge each time, it may get to a higher voltage and it will run a load a little longer. Just keep doing it and you will start to see improvement. -
#3 ·
Thanks for replying..
Its a 4,5Ah/12V and I started desulphation at 8 Volts. After a few cycles I realized it may be dry and added distilled water with a syringe.
It is hard to look inside because the holes are so small, but it looks very sulphated, white as snow.
Is C20 for charging, discharging or both? -
#4 ·
It sounds like you have a small AGM battery. Do not fill it with water, just a few drops once and awhile. These type are designed to hold the electrolyte within the separators. They are used in situation where the battery must be oriented sideways such as PC UPS systems, nothing to spill out.
They can be flooded but I don't recommend doing that until you have a good understanding of how they work. I flood them and add a little acid to make up for the dilution but it is a fine balance between too weak or too strong so for now just add a few drops of distilled water to replenish it and run it as it was designed to run.
They are not ideal for Bedini technology but you can play with it and learn from it for sure. The main reason they are not good for this project is because we are trying to push the battery to 15+ volts and this WILL start an electrolysis reaction (gassing). The original charging systems for AGM batteries never let it get past about 14.5V which keeps it from gassing, the gas is the water converting to hydrogen and oxygen which drys the cells. Also just be aware that this gas is highly flammable so be careful, especially connecting and disconnecting your leads. A little spark could ignite the vapor and believe me it's very powerful, like an M80 firecracker.
You do not want to pull more than .25A from it and that would be a bit much really. If you can find a 2 watt light bulb that would be just about right. You could use an 80mm PC cooling fan as the load also. -
#5 ·
Yes - I already flooded it haha! The white mass which I thought of as extreme sulphation must have been the glass mat.
I already got a lot of similar, 4Ah and 12Ah batts, all AGM's. LOL! That was before reading your post
P. Lindemann said on a video that there's little gassing with the chargers they make - so capdumping may be good for AGM's
I don't know if all their chargers use dumping, but the smaller ones do.
You can create the exactly right dilution and then floodfill them up, right? -
#6 ·
Hi Dinimus,
I guess its only for the discharging.. Charging Current is different from discharging current..so.
Rgds,
Faraday88. -
#7 ·
Yes I guess I wasn't clear about the C20, but that is on the discharge. Charging we can set many different rates and that is mostly the challenge with these systems, finding what works best AND most efficient.
Here is what I do in basic terms to salvage an otherwise useless AGM battery.
First I add distilled water to each cell, not full up but enough to make sure the glass mat is not bone dry. Typically the battery is sitting around 6 volts on it's own at this point but sometimes even lower. It has been sitting there for who knows how long killing itself by self discharge.
Now after it has been at least partially hydrated and has had time to soak it up I will apply a load to it, very small load like a small automotive bulb. I will have a voltmeter on it and literally as soon as I apply the load it will drop to Zero.
Now I have a small solid state coil I built with only one transistor and small wire 22AWG 75 feet on the power coil. I use this little coil to get things started, I also charge all of my small meter batteries and flashlight batteries with this thing but that's not the point in this post. I use this little guy because it has a relatively small power output. You may be able to achieve the same by just running your machine really low.
I will charge for about 5 min, and then drain it with the load again. You will hardly see anything happening the first 20 times or so that you do this. Eventually when you connect the load you will see that it is starting to produce some real amperage, the filament glows slightly and the voltage under load may show like 1v or so. This part of the procedure is just to sort of wake up the battery. It's the push/pull that starts to clear a little plate area.
Once it is starting to accept the charge and drain it off I increase the power and do a few runs still with the small coil. This is all done with regular radiant output ( no cap or conversion).
At some point it gets to where it is really starting to behave as a battery again. Then I splash a little acid in each cell and top them off with more water. For a really small 5AH AGM I would say about 2ml of acid per cell (Diluted already) the kind you get with new batteries to fill.
Now I take it to my bigger machine and start hitting it with a cap dumper. At first I have found it to be best to hit it with large pulses, what I mean is let the cap build up in voltage before dumping so that when it does you get a nice 4-6 amp pulse. The large pulse helps shake the plates clean. After more runs like this I will adjust the dump to be less powerful but more frequent. So for example I will start out with one dump per 2 seconds at 35-40 volts which hits the battery with 5A, then I will switch up to something like 1 pulse per second at 24 volts at 2A pulse. From then on it is just a matter of doing more cycles over and over.
Now with all of that said, you do not NEED to have a cap dumper to work on the batteries. That is just how I am doing it lately. I used not fool with cap dumpers at all and the same procedures with just straight radiant machine will work so don't be discouraged from trying if you do not have a dumper.
Not all batteries will come back, some of them will have a stubborn cell that is shorted out but you cannot know until you go through the cycles and observe the behavior.
Anyway I hope that helps ---Bob -
#8 ·
Hi Bob,
That was a very good briefing on the procedure on how it is to be done.
Best Regards,
Faraday88. -
#9 ·
Charge- Discharge cycling.
Hi Bob,
That was a very good briefing on the procedure on how it is to be done.
Best Regards,
Faraday88. -
#10 ·
Thanks Faraday, Just trying to share what has worked for me.
Something I didn't really mention in the last post that I should. At that initial phase when you are only hitting it for five minutes or so the voltage is going to look insane if you have a meter on the battery. The reason is that it is almost a dead short to the circuit. Again that is why I use the lower powered single transistor setup on very low power. If I dial the pot to high i WILL see the neon light up, so I run it very low. The idea is to keep it under 70 volts or so; otherwise the neon will light and burn off the power instead of it smacking the battery with it.
Just monitor things closely for heat. The transistor or the coil can heat up quite quickly if you are trying to throw to much power at it. Usually when I first start the meter will be around 65V or so and it will jump up and down a lot. This is expected as the plates are starting to barely accept the charge on tiny little sections. By the time you get it to where the load actually shows a little glow on the bulb the meter will be down closer to 20V or so. Basically what is happening is your machine is producing more energy than the battery can accept until it cleans its plates a bit.
Watching this high voltage freaked me out the first few times I did it but if you keep an eye on things and don't push on it for very long it works out fine.
Even when it starts behaving pretty well and you are hitting it with a dumper (or just radiant) for longer runs the voltages will spike and drop very abnormally. This is all part of the plates cleaning up. Eventually if you have a good salvage battery it will clear up and look like a normal charge curve.
@ALL
Remember I am describing a procedure for SALVAGE batteries. This stuff is not necessary on batteries that are already accepting charge. I have a bunch of 5AH AGM batteries that came out of UPS systems for computer data center racks ( I get them Free when they are replaced) . That is what I have brought back from the grave over and over doing this. It takes a lot of time and effort so it is not for everyone. It is always best to use NEW FLOODED batteries but If you can get something for free as I can than it is worth fooling with. -
#11 ·
Hi Bob,
I kind of do the same thing, but you seem to be more gentle on your batteries then I am
I want to mention something in my experience dealing with battery rejuvenation and see what is your approach.
I get batteries for free as well so I am less picky about which battery I accept to play with but so far I never had a lot of success with old "bulged" batteries. I understand that the sulfation is so thick that it is pushing the plates apart and end up pushing the plastic casing out of shape. I am always hopeful and thinking giving those battery a chance but it always end up being a waste of time. I am starting to think that ALL bulged batteries are too far gone to even try to recover them.
Has this been also your observation?
NoFear -
#12 ·
Hi NoFear,
Yes I agree with you. Especially in AGM's. The plates are really thin on most of them so any kind of warping will almost surely damage them beyond fixing. I do not even bother with one that shows bulging. I have noticed that on some of them at least that the bulging seems to come from improper venting. They are all supposed to have a one way vent for over charging but some that I have seen will gas out when I open them , as if it is under high pressure. Regardless of the cause, if it is bulging it is not worth messing with.
One trick for getting good salvage batteries is to try and get the data center UPS ones like I get. I am not talking about a homeowner style UPS that has just one or two batteries, these are trays of 5AH connected in parallel and series banks to make 48V. What usually happens is ONE of them malfunctions so the sensor on the UPS alerts that the batteries need replacing. Because they are all hooked up in a single bank the sensor is not smart enough to know the real problem, only that it is not getting the proper voltage. So what happens is the technician replaces the whole tray. There are 8 to a tray and usually one has gone bad. The rest can be brought back to life. They do get sulphate simply because the technician takes the whole tray out and it sits there slowly discharging on a shelf somewhere until I get it.
They are old batteries obviously because at least one has already failed and since they are intended for backup power the technician really has to replace the whole tray for reliability but many of them still have a lot of life in them. -
#13 ·
Hi Bob,
Thanks for confirming...
Are those batteries on a UPS tray what is referred to as the low hanging fruits?
With the batteries that I have dealt with, the only time I experienced that whoosh sound from opening a stuck one way valve is when the cell is actually below atmospheric pressure. I could see the walls being sucked in and they go straight back again after the air is let in.
I am presently working with 200Ah marine AGM batteries and I made the mistake to go to 15+V. I got some serious bubbling and the inside turned brown where it was a nice white until then. So from now on I capping my charging to 14V. Not sure how it is going to affect my desulfation effort if the chemistry is asking for finishing voltage beyond 15V? The adventure resumes....
Peace,
NoFear -
#14 ·
NoFear,
Yes I know what you mean about those that suck in air as well. The AGM is actually designed in a way that does involve internal pressure. Under normal operation it will "suck in" when discharging and expand out when charging. They are supposed to vent off if that pressure gets to large but what I was referring to is sometimes they do not vent out and start to bulge. The pressure keeps the mat evenly distributed with electrolyte but what we are doing when we open them up and add water is a whole different beast from how they are designed to work. As I suggested to the OP you can just put a few drops of water periodically on the mat but it becomes a balancing act. This is one reason Mr. Bedini has always said to use FLOODED batteries. He knows that AGMs can be used but they are such a pain in the arse it is almost not worth it (unless you get them free).
Good flooded batteries are getting harder and harder to find. There are plenty of starter batteries for cars but not storage batteries. With the advent of the internet and on-line purchasing most battery places push the AGM and GEL cells because they can SHIP them without restrictions, hence that is what is turning up everywhere. Also as is the case of UPS they are desirable because they cannot spill out, "maintenance free" what a scam! Sure they are maintenance free because you buy them , use them,toss them, and but more of them. -
#15 ·
I'm rejuvenating 2 gel cells, because they were expensive, and they have made very few cycles
196Ah@C20
I think their main problem is undercharging. And stood there for some years too...
Pushing to 15V sometimes but I think I will be stopping before 14.8 or earlier the next cycles. -
#16 ·
Dominus,
If they have been sitting a long time you do want to push them up to 15 at least a few times to help clean the plates. One suggestion would be to charge them at your normal rate but when they get up to 13.5 or so increase your power a bit to drive them faster don't worry about your efficiency on the primary, you are just trying to condition them without gassing off to much. That should minimize the gassing period a bit by bringing them up faster. Just don't do it too much or you will dry them out as previously discussed. -
#17 ·
No, don't go higher than 14.8 with gel-cells or they off-gas too much and dry out.
John K. -
#18 ·
I guess we disagree John but I said only a few times or they will dry out.
We went over all of the nuances earlier in the post. If they have been sitting for years than they are sure to have a good build up on them that will need to be cleared or he will never get capacity back out of them. -
#19 ·
Thanks guys!
I wasn't even sure about these 14.8 - yes, the difference can be heard from 14,9-15V up.
I'm using John's chargers as my SS are waiting one transistor+crocodile-clip experiments, and my SG-wheel is approaching it's final building stage.
The 10A12 is more gentle at pushing the voltage at the top than the 2A12-3. Less amps mean better structure on the plates...
D. -
#20 ·
Cannot comment on the chargers. Just to make sure you follow me don't push those things up past 14.8 on a regular basis if you decide to do it at all. It will mess them up. I was more suggesting you do it a few cycles is all.
Especially with GEL cells it can be beneficial to bubble them only once and awhile. The reason I say that is because the "GEL" is thick inside there and when you do partial charging from a normal charger you will develop tiny air pockets in the gel from where it starts to bubble occasionally. These can create tiny little voids at the plate surface area where the actual electrolyte is not touching the plate because of the air pocket. When you bring the voltage up it will liquify the gel and let the trapped bubbles escape the plate surface and recombine. Of course if you do it too much you will just boil out the electrolyte.
Ever made cookie dough or seen it being made. You know how you slap the tray down on the counter a few times to get the bubbles out, kind of like that. -
#21 ·
Gel cells and rejuvenation techniques are quite contradictory...
You'd like to push them very high but they start making bad digestion sounds
Too much and they'll boil dry. On the other hand you get more water into the Gel-mass by desulphating, because it´s stuck in the chemical structure!!
I should build a window into the side of these batteries to see how it looks like
Some years ago I heard that when you boil them, the bubbles stay in the gel and mess it up
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#22 ·
Yea,, That is why everyone agrees that flooded batteries are the best for the type of projects we work on. GEL/AGM are too finicky. Gels are even stranger than AGM in that regard.
Just give me a battery that I can simply add more water if I need too and be done with it ;-) -
#23 ·
Anyway, nice info about Gel's
Now I know really well why I have to stay far far away next time I stumble upon such a maintenance free sucker ^^ -
#24 ·
Hi Bro, what a surprise to have you jumping inBroMikey wrote:
I have a set of gel cells and they are jello compound trapping acid. They are Lead Acid. When these batteries need to be reconditioned this means that some of the gel is probably missing from the plates. I add ALUM, I don't care why I am not suppose to do it, I did it and it works.
Gel cells will start working better if you add electrolyte, or else why would my cells have very large screw off caps right? Add acid if you must I don't.
I never read anything and just added ALUM to the cells, when they are charged the Acid leaves the top in overflow and if need be I will overfill and charge and let them run over till I have what I want.
ALUM BATTERY that was an ACID battery.
Try it, the worst that can happen is that the battery will do alot better. My gel cells were overfilled and set on constant current til the plates are reforming. The ALUM must be heavy and the ACID must be lighter because like I said what runs over is ACID released from the gel.
I recently did this to two 50ah gel cells and two 30ah. They all went up the long slow way that all converted ALUM batteries do this is how I know it worked.
Mikey
Not sure about doing the Alum conversion to them yet.
I know Alums have lower voltage and deliver current much more steadily across the discharge voltage curve. That makes them pretty useless for powering loads with an inverter.
Is there any good link for these questions?
1. Do ALUM conversions increase the Ah?
2. (And/or) What makes an alum conversion superior to lead-acid?
Yes: http://www.hho4free.com/bedini_alkaline_battery.htm
Anyway, when discharging the batt, it stabilizes @8.5V or even goes up and down there while under load. The next charge takes longer, as well as the consecutive discharge.
Manufacturer recommends very long charging times at 14.1-14.4V
I´m making a pseudo topping-event at 14.8, by this I mean I disconnect the charger.
Both methods won´t give them a topping charge, but capacity is rising by going up & down.
This is the battery
And this is how the caps look like. Will have to find a tool that fits in there, eventually..
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#25 ·
Keep at it and hopefully they will come back.
The main thing is to cycle them anyway regardless of the fancier technique's I would start with a light load at first like whatever the c20 rate is, do half that. Long slow discharges will help.
I have some big AGM's that are similar, 100AH from PowerSonic. Those look like telecommunication rack batteries and they are well worth the trouble if you can get them working decent. They will run inverters fantastic.