Friday, March 27, 2015

Are We Suffering From Sulfated Batteries?

That is the question we are now exploring in our on going saga to solve our elusive battery charge mystery.

Here is a little of what I have learned, and take into consideration that I am even less skillful at science than at math. :)

Normally, a battery becomes sulfated as it discharges and the battery is termed completely discharged when there is no longer any lead active material remaining for the sulfate to react with.  You then need to recharge your battery by reconverting the lead sulfate into lead active material and returning the sulfate to the electrolyte so they can once again react with each other.

Now, here is what they now think happened to our new batteries.  In January, just after installing the new batteries, we took our trip to Wales for a week.  When we returned the batteries were totally discharged.  Obviously, we do not know how long they were in this condition but since the refrigerator and freezer were still cold/items still frozen it was not too long.

In February we were again away from the boat for a period of time and when we returned the batteries had again flat lined and we were not so lucky this time.  Everything in both our refrigerator and freezer had to be tossed.  Ergo, they had been flat for quite awhile.

When a battery is left in the discharged state for any length of time the lead sulfate becomes hard and develops a high electrical resistance:  it is a sulfated battery.  In this condition normal recharging will not break down the lead sulfate. 

And, if the battery has hard sulfate it will also show a false and higher voltage than it actually has when tested with a voltage regulator. 

To fix the situation and actually totally recharge the battery and get it back into working mode again it is necessary to recharge it with a low current to break down the hardened sulfate.  This is NOT a DIY job since the batteries can overheat internally and the specific gravity of the electrolyte in the battery needs to be monitored during this process.

So, on Monday all of our batteries will be removed and taken to an appropriate location where they can be slowly recharged and monitored.  During the week or so they will be gone we will be hooked up to shore power to keep all the systems on the boat functioning.

And, we will be keeping our fingers crossed that all of this will solve our problem.  (Please!)

Stay tuned for the next thrilling installment.


No comments:

Post a Comment