I found yet another manual for the whole Solar battery series range from BSB (the type of my batteries). It too says this:

"Constant voltage charging is recommended
Recommended float charge voltage: 2.27Vpc @20°C
Float voltage temperature compensation: -3mV/°C/cell
Float voltage range: 2.25 to 2.30 Vpc @ 20°C
Cyclic application charge voltage : 2.40 to 2.46 Vpc @ 20°C
Max. charge current allowable : 0.25C10A"

"And yet another manual for the same type of batteries says this:
Constant voltage charging is recommended
ŸRecommended float charge voltage: 2.25VPC @20-25°C
ŸFloat voltage temperature compensation: -3mV/°C/cell
ŸFloat voltage range: 2.23 to 2.27 VPC@20- 25°C
ŸCyclic application charge voltage : 2.35V/cell
ŸMax charge current allowable : 0.25C10A"

Even they can't make up their minds...

So according to this too I'm doing everything all right. Yet they're gassing...

 

Are you trying to charge cells that are already fully charged?

 

Not exactly. They were about 90% charged whn I started charging them.

 

You need to accept the fact that a manufacturer is not some golden source of immaculate information.
They are just people and mostly, people are incompetent, and motivated to mediocrity under pain of termination in matters of employment.

Listen to the battery young Jedi. It knows how it wants to be charged. (90% capacity almost doesn't need a charge cycle. I'm sorry if you are wasting solar power)

 

Thank you, Master Jedi Today I'm discharging it to 75% and tomorrow I'll charge it and keep an eye and an ear on it, see what happens...

 

Thank you, Lestraveled! I did try contacting the manufacturer, but they are some huge Chinese company and they don't really give a ... about small clients like me. They never bothered to answer me. So my only hope lies in figuring it out myself...

It's not a problem that the charger's voltage thresholds are not set correctly from factory because I can change them. I just don't know what values to use. The 13.6V for float and 14.1V for absorption seemed a good choice, until I realized that I hear these sounds even at 13.5V.

Last time I contacted Yuasa, they sent me various pamphlets etc - some more useful than others.

I didn't bother to mention that I wasn't using one of their batteries though.

Best thing to do is search online for their nearest equivalent, and quote that model number in all correspondence.

 

This story is taking an unexpected turn...
I haven't charged the batteries for about 40 hours now. I have been discharging them in the last 40 hours very gently, at about 1-2A and I have drawn from them about 800-900Wh (about 30-35Ah) in this time frame, so now they should be discharged to about 75%. I'll attempt to charge them like this and see what happens.

But the amazing thing is that this morning, after they have not been charged for 40 hours, I put my ear to them (at this point an 1.5A load was on them). Now guess what I heard?! An ever so slight stir/fizz. How the hack can this be? Can they still gas after 40 hours since the last charge? Or maybe this sound is not what we think it is at all? I've disconnected all the loads, I'll let them rest for half an hour and listen to them again. Of course this stir/fizz that I heard now was much much more light compared to the one that I heard during charging. But it was there! Now that's very strange...

 

(Don't forget to read my previous message)
After letting the batteries in a complete rest state (no charge, no load), all sounds have stopped.
Then I've connected the charger. In the first two minutes no sound. After two minutes I've heard the first stir/fizz. At this point the charger was putting into them 0.3-0.4 A and the voltage of the two batteries in series was 25.4V (12.7V per battery). These sounds are far apart (about one sound every 20-30 seconds) and barely audible. But I'm guessing that as the sun rises and starts facing the solar panels directly, the charger will be pushing in more current and the sounds will intensify.

Maybe the batteries are simply making this sound when current goes in or out? If so, is this a problem or is this normal? Perhaps I should try to charge or drain them individually to see if both of them make the sound or just one of them.

 

Now the charger is putting in 3A, the battery voltage is 26.4V (13.2V per battery) and I can't here any sound. So this eliminates my theory that simply putting in or out current makes the sound.

 

If these are brand-new batteries, perhaps small pockets/bubbles of air trapped during the manufacturing process are finding their way out, movement being helped by very localised warming of the electrolyte as current flows in or out? Just a thought.

 

I discharged the batteries down to 75-80% 3 times already and charged them back. I can't hear any movement anymore during discharging (not even at 8-9 Amps coming out), but I can still hear significant sounds during charging.

I'm charging them at 13.55V and I can still hear sounds like bubbles moving in liquid and sounds like the ones made by metal springs when they are released. I tried charging them in series, in parallel, individually. The sounds are the same. The sounds are not there when I start charging them for quite a while, but after a couple of hours, the sounds begin.

I don't understand what's going on. I don't think it's possible to overcharge them at 13.55V, even if they are gel cells, is it?

 

I'm wondering if the automatic DC fuse that I put between the charge controller's battery terminals and the battery itself could in any way cause problems.
The solar charge controller's battery terminals are connected to an automated DC fuse like this one:
http://www.ada-electric.ro/siguranta-curent-continuu-2p-20a-c62dc-6ka-curba-c-elmark
The battery is connected to the other side of the same automatic DC fuse.
I use this fuse mostly as a switch to connect/disconnect the battery.

It seems it has nothing to do with it. Eliminated the fuse for 15 minutes, the sounds are just the same...

 

I can't manage to solve the problem. Bubbling/stirring is still heard during charging. What I know is this:

• After a fair discharge (of at least 20%) the sounds are nt present in the first 1-2-3 hours of charging.
• The sounds start to appear as the battery is getting close to being fully charged. The sounds start at voltages as low as 13.4V. They seem to become stronger as the charging voltage increases.
• At 13.8V I hear this bubbling/stirring sound at least once in every 5 seconds (maybe even more frequently), but it's definitely not as strong as it was at 14.4V (when I charged the batteries at higher voltage).
• The batteries do not warm up at all during charging, not the slightest bit.
• The batteries are supposed to have a gas recombination system.
• The batteries are made of some kind of "solar nano gel" with AGM separator.

I don't know what to do.

The manufacturer recommends float charging at 13.6-13.8V and cyclic charging at 14.4-14.8V. The reseller who sold me the batteries says never to go above 13.8V. Every online manual and other document about these batteries recommends at least 14.1V absorption voltage and says that at most 0.25*CA current can be used to charge (in my case 150Ah batteries can take 37.5A but I'm only charging them with 5-6A max).

On one hand I fear that by not forcing a fair absorption, the batteries will never be 100% charged and will experience sulfation. On the other hand I fear that this bubbling/stirring is the sound of gassing and the batteries are losing water. Both can cause premature death of the batteries. If I assume that this bubbling/fizzing is OK because of the gas recombination system (although I doubt that it is OK), I could set the absorption voltage to 14.1V (which is still way below the manual's recommendation of minimum 14.4V). If I want to be more cautious and believe the reseller, I'll set the absorption voltage to 13.8V, which is till causing these sounds but I might risk sulfation too.

I can't figure out what is the best way to go. At this point I'm starting to get used to the idea that my batteries worth 700$ are going to be killed prematurely either by gassing or by sulfation, because I simply have no idea how to charge them correctly and avoid both gassing and sulfation, in spite of the hundreds of articles, forum posts and manuals that I've read in the last few weeks. If I knew that there are going to be so many problems with charging, I never would have invested in such a system.

 

After hearing consistent bubbling even at voltage levels as low as 13.4-13.8V, I wrote to the manufacturer again and this time they have responded. They say that as the battery gets close to full charge it's normal to have some gassing (yes, we all know that) and that to some degree these should recombine inside the pressurized battery, but that if I keep hearing bubbles, that's not good. They suspect that the pressure release valves might not be calibrated correctly and that they are releasing gasses at too low pressure values and that's what I'm hearing. They've offered to take back the batteries and give me another set of new batteries. They will check the current ones and I will check the new ones. this way we'll find out if the problem is with the batteries or with something else. So now I'm waiting to get the new ones, see if those make any sounds. The saga continues...

 

OK, so I got the new batteries from the manufacturer. They had some quite high voltages when they arrived (around 13.2V). When I got the previous set, they had 12.93V. Anyway, I drained about 300-400 Wh from them (about 10% capacity) last night and today I proceeded to charging them at 13.5-13.7V (13.7V absorption, 13.5V float). Only a few seconds after connecting the charger, I was faced with the familiar sounds (like gas moving in liquid and like small metal springs going off). At that point the voltage of the batteries was around 13.3V and today it never climbed above 13.5V because I only left them charging for about 30 minutes. The sounds are far apart (about 10 seconds) and quite faint, but they are there. I don't understand what's going on. I don't think they can be overcharged at 13.5V. So why are they making those sounds during charging? The previous set of batteries and the new set of batteries behaves the same way. This is going to drive me nuts unless I start not caring about it very soon...

 

The sounds are far apart (about 10 seconds) and quite faint.

Quit sitting there listening to it with a stethoscope all day. If a tiny bubble every 10 seconds is normal for that battery, the battery will behave normally. If that battery design is crap, it will fail too soon and you will buy a different brand next time.

 

Thanks

I don't think that the design is crap. I have a battery of the same type (only much smaller: 12 ah). I have it for more than 4 years and it does not show any sign of decline, although I haven't used it very much...

So you think that it might be normal for the battery to make a sound every 10 seconds or so? Even if it sounds like a metal spring going off? In other words like some release? The strange thing is that the sounds only start being there when the battery nears full charge. When it's discharged to 75%, there's no sound for a couple of hours during charging.

I'm not only worried about losing the battery prematurely. It worries me that they release gasses because they are kept indoors and yes there can be an occasional spark in that storage room.

 

Hello Everybody!

I too have a bubbling/fizzling sound when charging my brand new AGM batteries and I'm kind of worried.
I have 2 pieces of BSB Power sealed lead acid 150 Ah batteries (AGM, VRLA) wired in series in a 24V system.
I charge them from solar panels. The charge controller is a Victron Energy BlueSolar MPPT 100/15 charger with 3 charging stages: bulk (apply as much current as possible), absorption (apply 14.4V per battery) and float (apply 13.7V per battery).
The battery manufacturer recommends a charging voltage of 14.4-14.8V during the absorption stage and 13.6-13.8V during the float stage.

The bubbling sound only starts in the absorption stage (14.4V per battery, 28.8V in my 2-battery system) and stops in the float stage (13.7V per battery, 27.2V in my 2-battery system).
I did measure the voltage of the batteries when the sounds is audible and the voltage stays all the time at 28.8V, which is at the lower and of the charging voltage recommended by the manufacturer for this stage. I also touched the batteries and they are not hot, they are not even warm a little bit. So I think it's not likely that they are being overcharged.

This bubbling sound seems to be coming more from one of the batteries than from the other, although it's hard to tell because they are right next to each other. I measured the fully charged voltage on them individually and they both stay at around 13V with no load when fully charged, so it's unlikely that any of them have damaged cells.

The opinions on the Internet are different. Most people say that AGM batteries should not make a bubbling sound. A few people say that it's OK. What do you think, should I be worried? Is it possible that it's only because the batteries are new and it will go away with time? Maybe I've been sold some defective or old batteries?

HI new to your forum, my explanation to the bubbling sealed battery is exactly what they are sealed nowhere for the gas to escape, the battery is actually 2 parts an upper and lower, the upper act as condenser with a small hole between the 2 parts the liquid all ready condensed returned back to the lower main part and at the same time as the gas goes up words jou get the bubbling sounds the same as blowing through a straw in a glass of water, some batteries have bigger wholes to compensate for the sound, this is normal not to worry.

 

mikeileen, I'm tempted to believe your theory, but if the battery is not being overcharged, why is gas forming in the first place? I also find it strange that when I contacted the re-seller about the sounds, they never have heard about such cases and they offered to replace the batteries instead. If it's normal to have these sounds, the seller and manufacturer ought to know about it, right?

 

I would like to see if your problem is solved if you replace the battery with the same make and model thanks.