Sulphurating Batteries

[Chris]

We have now had a second set of batteries (AGM's) die on us, within a twelve month period. Clearly something is wrong.

The battery supplier who replaced them FOC as they were under warranty, said they had sulphurated. I have done some internet checking and discovered that this process of damage occurs when certain factors are present. Such as:

Battery life and performance - Average battery life has become shorter as energy requirements have increased. Two phrases I hear most often are "my battery won't take a charge, and my battery won't hold a charge". Only 30% of batteries sold today reach the 48-month mark. In fact 80% of all battery failure is related to sulfation build-up. This build up occurs when the sulfur molecules in the electrolyte (battery acid) become so deeply discharged that they begin to coat the battery's lead plates. Before long the plates become so coated that the battery dies. The causes of sulfation are numerous. Let me list some for you.

◦Batteries sit too long between charges. As little as 24 hours in hot weather and several days in cooler weather.

◦Battery is stored without some type of energy input.

◦"Deep cycling" an engine starting battery. Remember these batteries can't stand deep discharge.

◦Undercharging of a battery to only 90% of capacity will allow sulfation of the battery using the 10% of battery chemistry not reactivated by the incompleted charging cycle.

◦Heat of 100 plus F., increases internal discharge. As temperatures increase so does internal discharge. A new fully charged battery left sitting 24 hours a day at 110 degrees F for 30 days would most likely not start an engine.

◦Low electrolyte level - battery plates exposed to air will immediately sulfate.

◦Incorrect charging levels and settings. Most cheap battery chargers can do more harm than good. See the section on battery charging.

◦Cold weather is also hard on the battery. The chemistry does not make the same amount of energy as a warm battery. A deeply discharged battery can freeze solid in sub zero weather.

◦Parasitic drain is a load put on a battery with the key off. More info on parasitic drain will follow in this document.

Ref: http://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html

Given that we store the van inbetween our regular trips with the batteries being "smart charged" and never discharge them below the 60% level and always top up to 100% after discharging, where are we going wrong?

I don't think we have any sort of load on the van while it is being stored.... is that a solution?

Chris

[RussnSue]

Hi Chris

This certainly is puzzling. AGM batteries are not usually as prone to sulphation as normal wet cell batteries are. I took the AGM batteries out of our van after four years (the original ones, supplied by Kedron) and they tested almost as good as new. I had no qualms selling them to a mate for $50.00 each.

If you have a maintenance or trickle charger on them when you aren't traveling, make sure that you check the voltage of the batteries from time-to-time, to ensure that the batteries aren't overcharging. Some maintenance chargers are notorious for doing that.

The only other thing I can think of is that while the State of Charge readout might indicate that you have only discharged the batteries by "X" amount, this may in fact be incorrect. When I picked up our van from Kedron the Shunt that measures the current going into and out of the batteries was wired arse-up. This meant that the regulator thought that the current going into the batteries from the charger was the Load current being supplied to the appliances and it thought that the load being used by the appliances was what was coming out of the charger. You can imagine how this would have played merry hell with the internal calculations that the regulator performs. It was lucky that I sussed it out and had them fix the problem.

In another thread I posted a rough guide of battery voltage and what it equates to in terms of State of Charge. You might want to compare each (battery voltage measure by a multimeter and SOC as indicated by the regulator) and see if they agree. Monitor this over a period of about a month and see what you get.

It is possible that the SOC might have indicated, say 70%, but in reality might have been only 40% as an example. Continual deep-discharging of an AGM battery will definitely shorten its life expectancy.

Cheers

Russ

[Mayzee]

Hi Chris

Like Russ I can't see how you have a sulphation problem with AGM batteries. With wet cells you.can fix the problem with a product called Batrolyte

Regards

John

[Zolle]

We have now had a second set of batteries (AGM's) die on us, within a twelve month period. Clearly something is wrong.

I don't think we have any sort of load on the van while it is being stored.... is that a solution?

Chris

[RussnSue]

Hi again Chris,

I just read John's post (above)and thought it would be worth adding that I also store the van uncovered so that the solar charger is managing the batteries and I also leave the fridge running (not to give the batteries some load, because that doesn't matter, but because I have also been told that a fridge is better of if it is running.)

Letting the solar charger manage the batteries is a good practice, provided it is set up correctly. Maybe that is the problem? Perhaps Val could make a note of the settings and you could publish them here, so that I can take a look at them?

Cheers

Russ

[Chris]

Thanks everyone for your time and thought in providing responses.

I will talk to Val about all this advice and get back to you all. On Caravaners Forum it has been suggested the brand may be the issue; someone else in Adelaide is having the same issues. Russ, I will check with Val and advise. Your expertise in this area is valuable, I know.

But I like the idea of a device which preents sulphation/sulfation....can you tell me more about that Zolle?

Chris

[Zolle]

Thanks everyone for your time and thought in providing responses.

I will talk to Val about all this advice and get back to you all. On Caravaners Forum it has been suggested the brand may be the issue; someone else in Adelaide is having the same issues. Russ, I will check with Val and advise. Your expertise in this area is valuable, I know.

But I like the idea of a device which preents sulphation/sulfation....can you tell me more about that Zolle?

Chris

Chris

Try this link

/>http://www.megapulse.net/products/first-aid-for-batteries-fab-mk5.html

The one I have is several years old .

Cheers

John

[Mayzee]

Hi Chris,

Not sure the Megapulse would solve your problem. I heard about it a couple of years ago and asked Springers Brisbane (12V specialists used by many Koggers) about it. They said our 3 stage float charger does the same thing. Our original batteries only lasted 2 years before packing it in and we were very careful not to let them drop below about 12.4 volts. While at home we turn everything off including the fridge and leave the van under a cover with 3 clear Plastic? covers, one over each solar panel. We noticed that when we then connected to mains power charging commenced immediately. Was that a factor in reducing battery life? I don't know but with our new batteries we now leave mains power connected all the time we are home. We have found that it is difficult to find someone really competent with 12V systems. Because of problems with the fridge at night we visited two battery specialists in WA during our 2011 trip, both (one of which was Battery World)checked them and said they were OK. When Springers Brisbane checked them they advised us to replace them and sure enough that fixed the problem. I'm not having a cheap shot at the WA guys as I'm sure there are plenty of good 12V people there,just highlighting how difficult it seems to be to get really good advice for 12V systems.

[Danny and Sue]

HI Chris

When we are home i have a 5amp Ctek charger that i leave plugged into the anderson plug.once a month i turn it off and turn the fridge on for 5 hours or so..Ctek is $105 with a 5 year warranty.recon this is better than running the zantrex all the time.I also take the Ctek with us as i have found that the zantrex will show an error if voltage is too high or low..257 volts at Cunnamulla last year..

so far no probs..

Cheers Danny & Sue

[Chris]

Again thanks everyone. Now we are analysing all this information...

I will get back with progress.

Chris