Battery desulphuration?

[Doodlebug]

Hi all,

 

This sort of follows on from another problem in another thread but for the sake of other people searching for topics i've made a new one.

 

Our batteries were subjected to a bit of abuse during the winter, in that we had a crappy charge controller that wasn't fully charging our batteries.

 

Then it was suggested for the winter I should hardwire the solar panels to the batteries until it gets sunny enough to be overcharging them.

 

I know they were overcharged on at least two occasions because the carbon monoxide detector was going off, indicating hydrogen.

 

Today ive been investigating the problem, and (in the other thread) I have the problem of voltage drop between the controller and batteries. Anyhow, I figure that hasn't helped the problem.

 

Ive opened up the batteries to top up the water, and shone my torch down and can just about make out thin lead plates with a white sandwich of white stuff.

 

From a bit of googling I get the feeling they are very sulphated.

I have seen this on ebay, and have looked up reviews on youtube and it seems to work wonders on dead batteries.

 

I've charged them all day, and having now disconnected the isolation switch for the last half an hour, the batteries are now at 12.6.

 

I'm going to wait as long as possible to see what it stops at, but I need to have some electric power back on soon.

 

Are my batteries dead? Is a desulphering thingy a con? And is there anything I can do to fix the problem?

 

Ive just bought two new batteries to add to the bank. I dont want to have to buy another two!

 

Thanks everyone.

 

Doodlebug

[jelunga]

Hi all,

 

This sort of follows on from another problem in another thread but for the sake of other people searching for topics i've made a new one.

 

Our batteries were subjected to a bit of abuse during the winter, in that we had a crappy charge controller that wasn't fully charging our batteries.

 

Then it was suggested for the winter I should hardwire the solar panels to the batteries until it gets sunny enough to be overcharging them.

 

I know they were overcharged on at least two occasions because the carbon monoxide detector was going off, indicating hydrogen.

 

Today ive been investigating the problem, and (in the other thread) I have the problem of voltage drop between the controller and batteries. Anyhow, I figure that hasn't helped the problem.

 

Ive opened up the batteries to top up the water, and shone my torch down and can just about make out thin lead plates with a white sandwich of white stuff.

 

From a bit of googling I get the feeling they are very sulphated.

 

I have seen this on ebay, and have looked up reviews on youtube and it seems to work wonders on dead batteries.

 

I've charged them all day, and having now disconnected the isolation switch for the last half an hour, the batteries are now at 12.6.

 

I'm going to wait as long as possible to see what it stops at, but I need to have some electric power back on soon.

 

Are my batteries dead? Is a desulphering thingy a con? And is there anything I can do to fix the problem?

 

Ive just bought two new batteries to add to the bank. I dont want to have to buy another two!

 

Thanks everyone.

 

Doodlebug

Do not assume "the white stuff" is lead sulphate. It is more likely the separator a. De sulphation requires a long slow charge. A fast charge will tend to "fix" the sulphate not remove it. Check the SG also if you have a hydrometer. But certainly slow charge at c/ 20 amps max. Well that's wot the army taught me.

[MtB]

I know they were overcharged on at least two occasions because the carbon monoxide detector was going off, indicating hydrogen.

 

You have me intrigued now. My CO detector went off the other day on Aldebaran. A bright sunny day with the front, back and side doors open, and no fossil fuels being burned. Just the solar panel punching 8amps into my tired and knackered pair of domestic batteries.

 

What makes you say a CO detector will detect hydrogen? Could this have been the reason my CO detector sounded?

 

 

MtB

[Doodlebug]

What is the separator? Is it like white paper? It could be that, but it looks similar to this:

 

http://www.batterydoctorswi.com/images/album/big/18.jpg

 

I dont have a specific gravity checker, but the batteries do have a magic eye that checks one of the cells SG.

 

That tells me that it isn't fully charged, or in other words the specific gravity is too low.

[dmr]

A hydrometer really is the right tool for the job here.

Give the batteries a big long charge then measure specific gravity, if its low then you almost certainly have sulphation.

Do a long controlled over charge (equalisation), 15.5 volts for about 8 hours. Measure the specific gravity again, if its improved then maybe equalise more till you can't get it any higher. If its not improved then based on how low it is decide if you need new batteries or if you can live with the lower capacity.

 

..........Dave.

[Doodlebug]

You have me intrigued now. My CO detector went off the other day on Aldebaran. A bright sunny day with the front, back and side doors open, and no fossil fuels being burned. Just the solar panel punching 8amps into my tired and knackered pair of domestic batteries.

 

What makes you say a CO detector will detect hydrogen? Could this have been the reason my CO detector sounded?

 

 

MtB

 

That was exactly the same with us, pretty much. The CO detector went off at around 2pm on both occasions, pretty much when the sun was highest and strongest.

 

I googled it, and CO sensors (there are two types but one of them) can be triggered by other gasses such as hydrogen, and I think it was methane.

 

It sounds like your batteries are overcharged.

[dmr]

You have me intrigued now. My CO detector went off the other day on Aldebaran. A bright sunny day with the front, back and side doors open, and no fossil fuels being burned. Just the solar panel punching 8amps into my tired and knackered pair of domestic batteries.

 

What makes you say a CO detector will detect hydrogen? Could this have been the reason my CO detector sounded?

 

 

MtB

 

I think it might be hydrogen sulphide rather than hydrogen, but I've read that it happens on this forum and experienced it myself!

 

............Dave

[Doodlebug]

I forgot to add the link,

 

http://www.ebay.co.uk/itm/150999423966?_trksid=p5197.c0.m619

 

Its had a pretty good charge today, but ill try your idea (dmr) and see if it helps.

 

I can live with the reduced capacity, because I am adding two new batteries. As long as they dont kill each other it should be ok.

 

Bearing in mind we live aboard, they will be charged and discharged every day, so I dont think they would have much time to kill each other. They will either be on a mppt charger by day or be discharged to a point they would all be identical at night.

In fact, that picture I posted is different. The white stuff in my batteries is only between the plates. I can see the lead on the top of the plates. It could just be a white cloth paper thing to keep them apart.

 

In which case I dont understand why my batteries aren't behaving. Ill get a SG thing and see what they say.

[Higgs]

What makes you say a CO detector will detect hydrogen? Could this have been the reason my CO detector sounded?

 

 

According to some information I read on the internet, at a time my CO detector was going off alot while charging, !000 ppm of hydrogen will give a reading of something like 34 ppm on the CO detector. Approximate.

 

 

I've recently purchased a Sterling desulfator. It only works with the votage at 12.8v. With a battery that's playing up, this means that the charger will at least have to be on float to maintain that switch on 12.8v. Left on a weak battery, without a charger, the desulphator will only work after a charge and very shortly switch off and do nothing. I think these desulphators are probably best used on new batteries that are getting a suitable charge regime from the start. Trying to desulphate a sulphated battery can take a long time - may be weeks.

 

As I'm working on a couple of weakening batteries, I'm also looking at Epsom salts (magnesium sulphate). It may be a con, I'm not sure of the chemistry. Not much to lose, the batteries are due for replacement.

Edited May 12, 2013 by Higgs

[blodger]

I forgot to add the link,

 

http://www.ebay.co.uk/itm/150999423966?_trksid=p5197.c0.m619

 

Its had a pretty good charge today, but ill try your idea (dmr) and see if it helps.

 

I can live with the reduced capacity, because I am adding two new batteries. As long as they dont kill each other it should be ok.

 

Bearing in mind we live aboard, they will be charged and discharged every day, so I dont think they would have much time to kill each other. They will either be on a mppt charger by day or be discharged to a point they would all be identical at night.

 

In fact, that picture I posted is different. The white stuff in my batteries is only between the plates. I can see the lead on the top of the plates. It could just be a white cloth paper thing to keep them apart.

 

In which case I dont understand why my batteries aren't behaving. Ill get a SG thing and see what they say.

 

There are some addatives that ca be used in the electolyte to ais slow charging desulphating your batts.

 

Epson Salts solution is the cheapest and I try this as a last resort before having to ditch them.

 

EDTA is similar, a bit more expensive and, seems to result in a better less capacity battery.

 

Batt Aid tablets from Granville Ind, available from Halfords or motor factors (&EBay) about 4.00 for 12 tabs probably comprised from some of the above. Often regarded as snake oil but I find help batts through the winter for another season.

[jelunga]

What is the separator? Is it like white paper? It could be that, but it looks similar to this:

 

http://www.batterydoctorswi.com/images/album/big/18.jpg

 

I dont have a specific gravity checker, but the batteries do have a magic eye that checks one of the cells SG.

 

That tells me that it isn't fully charged, or in other words the specific gravity is too low.

One battery seller told me that the magic eye is as much use as a chocolate teapot. Looks impressive but is of no practical use

[smileypete]

Why not just keep them properly topped up and see how they are after a summer of charging by solar.

 

cheers, Pete.

~smpt~

[MtB]

Why not just keep them properly topped up and see how they are after a summer of charging by solar.

 

cheers, Pete.

~smpt~

 

Yes, the instructions in my Tracer say it's charge regime includes an equalisation charge period. This seems a good reason alone to use Tracer MPPT controllers in particular.

 

MtB

[BruceinSanity]

According to some information I read on the internet, at a time my CO detector was going off alot while charging, !000 ppm of hydrogen will give a reading of something like 34 ppm on the CO detector. Approximate.

 

ISTR that we were told on another thread that CO detectors commonly use a Wheatstone bridge set up with one of the resistors sensitive to reducing gasses, so hydrogen sulphide and methane will both trigger it. I guess hydrogen is also a reducing gas as it will oxidise to water over time if not ignited.

 

When on the dock at Norbury last week the charger stayed on absorption for quite a while after I connected the shoreline. In the confines of the dock there was no ventilation through the engine room and the CO monitor in there started showing 34 ppm. Gave me quite a fright initially, but checking the batteries found that they weren't getting even warm and had used only the usual amount of water in the month since last checked, so I guess they were just gassing off a bit.

 

Moral: make sure that batteries are well ventilated when under charge...

[Biggles]

I was told my someone that is " interestingly" regarded in the battery charging industry that my 1180a/h 6 x 2v traction cell batteries should be de-sulphated thus:-

 

Get a 24v charger with current limiter to 50amps. Connect up and watch the voltage which should settle at about 17v, keep watching and in time the volts will drop to about 10 at which point the de-sulphation is happening. Keep watching until the volts return to around 14 at which point the job will be done.

 

I have to say putting 24v on them sounds a bit harsh.

[larryjc]

Sulphation normally occurs when batteries are allowed to go flat. I had three of them on a boat some years ago and we 'recovered' them by a 24 hour charge at 17 volts. The reality is that if they are sulphated you will never get them back fully. However I have not heard of sulphation caused by overcharging. you can do other sorts of damage though - buckling the plates due to overheating etc and can even blow them up - see the other thread on it.

Solar panels should not overcharge batteries if they have any half way decent controller, one of their main benefits is to keep batteries fully charged when you are away. Edit - noted that you said you 'hardwired' the solar panels - does this mean you connected them without a controller - they normally produce 19 volts and that will really screw your batteries!!!

Edited May 13, 2013 by larryjc

[Doodlebug]

Interestingly, of the two batteries, bought new at the same time, one settles at 12.6 and the other at 12.65.

 

They seem by the looks of the voltage to be recoverable, but why the amphourage has gone down so much I dont know.

[larryjc]

Interestingly, of the two batteries, bought new at the same time, one settles at 12.6 and the other at 12.65.

 

They seem by the looks of the voltage to be recoverable, but why the amphourage has gone down so much I dont know.

Er - what do you mean by 'amphourage'? If they have been abused - either over charged or allowed to go too flat they will be damaged to some degree and their capacity will be reduced. laws of chemistry I'm afraid.

[Richard10002]

Interestingly, of the two batteries, bought new at the same time, one settles at 12.6 and the other at 12.65.

 

They seem by the looks of the voltage to be recoverable, but why the amphourage has gone down so much I dont know.

Let's say that they are 90% full at 12.6V and about half full at 12.2V, how many amp hours do you get to use between 12.6V and 12.2V? How are you measuring this?

 

And how many amp hours did they start at, I.e. the sum of the amp hours of each battery when new?

 

Armed with this info, you/we can see how much capacity has been lost, and make a judgement as to whether they might be worth persevering with, or whether they should be scrapped and replaced.

 

For example, I have 3x110Ah batteries, total 330Ah when new.

 

Between full and 50% full, (12.7V and 12.2V), I now get to use only about 30Ah. I measure this on a NASA BM2 monitor. I know my batteries are shot, and I'm currently looking at buying some new ones.

[Doodlebug]

I cant be sure, but tonight, I had my laptop plugged in for three hours using five amps, and the lights, using two amp for about six hours. So 27, yet the inverter has just cut off the power to the laptop. So from the 220ah of batteries we can only use a fraction of this

 

By amphourage i mean the number of amp hours avalable, like mileage but for batteries

[blodger]

I cant be sure, but tonight, I had my laptop plugged in for three hours using five amps, and the lights, using two amp for about six hours. So 27, yet the inverter has just cut off the power to the laptop. So from the 220ah of batteries we can only use a fraction of this

 

By amphourage i mean the number of amp hours avalable, like mileage but for batteries

 

I am sure you realise that your 220ah even when brand new should not have been used for much more than 30% of their capacity 66ah before fully recharging to prolong their life. Each day of use and cycling reduces their capacity and sadly even if they are not used they slowly loose charge, etc.. If drawing 21ah out of them in three hours from fully charged has them discharged sufficient for the inverter to go on holiday then, either they are goosed or, they were not fully charged in the first place. A charging regime which continually short changes them in fully charging them soon depletes batteries and has them sulphating up. It is not clear whether your solar has been able to overcharge them, meaning a knackered controller, or more likely been overwhelmed in trying to keep up with your usage, etc

[Doodlebug]

Yes I know they shouldnt be discharged to that extent. Our solar array has no problem topping up the batteries each day, but i am having voltage drop problems, (see the other thread) so there is a possibility the batteries have always been charged to 0.3v below what the charge controller thinks it is doing.

 

Even so I swear three days ago we were getting more out of the batteries than we are now. All ive done is increase the thickness of the wires and topped up the water in the batteries.

 

Ive bought a desulphating thing so that might help.

[Richard10002]

I cant be sure, but tonight, I had my laptop plugged in for three hours using five amps, and the lights, using two amp for about six hours. So 27, yet the inverter has just cut off the power to the laptop. So from the 220ah of batteries we can only use a fraction of this

By amphourage i mean the number of amp hours avalable, like mileage but for batteries

Not particularly scientific then but you would expect a bit more out of a 220Ah battery bank, particularly if it was around 90% full at the start of the night. If they had lost no capacity, you would expect to have about 80-90 useable Ahrs between 90% and 50% State of Charge.

 

Looks like you don't have a fridge?

 

Can you power the laptop with a 12V adaptor. Invertors use some power to run, even if supplying nothing, and they lose some power in the conversion. If the laptop charges at 5A all the time, and it was charging for the full 3 hours, it will have used more than 15Ah.

 

The inverter may/will be cutting off the power because the voltage has dropped below a preset level. This could be as much to do with the wiring between battery and inverter, as the state of the batteries.

[Doodlebug]

Nope no fridge.

 

I know, its hard to be scientific when living on board, when I can add in the new Btteries I can do a better set of testing. The five amps being used is whatbws going into the inverter, so its not that.

 

I wish it was easier to get to, then I could really analyse it. I wonder if its possible that, for instance, the master switch is faulty and is, for instance, heating up, causing a large loss of energy through that point.

 

It would also explain the voltage drop, but is that possible?

[MtB]

I think only about 25% of the capacity of a battery is available for use without over-discharging it, so your 220 amp-hour batteries should give you 55 amp-hours before you need to recharge.

 

But I don't know much about batteries, yet.

 

MtB