I have a set of new batteries, however, they are 6 years old. I've never used them. Can they be restored?
Maybe, but I think much depends on how they've been stored. 6 years is a long time for a lead acid battery to be stored, and they don't like heat or being stored with low or no charge.
Battery University says: "Sulfation may prevent charging small sealed lead acid cells...after prolonged storage. If seemingly inactive, these batteries can often be reactivated by applying a higher than normal voltage."
I'm guessing from the way that you asked the question that the batteries won't take a charge, and what you're really asking is how to desulphate them. You have to set a charger to a higher voltage than the 6 volts, and you have to watch it - Battery University describes the process if you go to Battery University and do a little reading.
So your options are you can do the desulfation yourself, or you can buy a battery desulfator like the one in the video (I have no business relationship with them, btw, and there are other battery desulfators around if you do a search).
No guarantees it will work after 6 years, but it's worth a try.
I have some older 6 volt batteries that have been drawn down over time in storage. Is there a way to revive them? They charge, but only up to 5.5 volts.
Hi, Hugh - If your SLAs (sealed lead acids, hehe) have got a mild case of sulphation, Battery University says you can restore the batteries by applying a "charge on top of a charge". That means charge it fully, let it rest quietly for a day or two, then hit it again with the charger 'til it's full.
The vented type of lead acid batteries need a little different treatment, and I guess that's why the fancy desulphating charger in the video above costs 1500 bucks; it must be programmable.
It had better be able to make breakfast and do the laundry for that kind of money, right?
Right! Sulphation is what happens to lead-acid batteries as they age, and de-sulphation is the "cure". Uh, more or less; )
Here's the chemistry: The acid in the Lead-acid battery is sulphuric acid, and in the process of charging, the battery plates in their acid bath are prone to coughing up sulphide crystals. These crystals either float loose in the acid or attach themselves to the plates and such, slowing or stopping the flow of electrons needed in the business of charging and discharging. Enviroharvest (an alternative energy company in Ontario) says that "Sulphated battery plates (are) the primary cause of poor battery performance."
They go on to say, "A good desulphating unit uses sharp pulses of current at 800 KHz to set up a resonance which "jars, crushes, grinds or dissolves" sulphide crystals...so they can be recombined into the sulphuric acid of the battery electrolyte."
They did mention that desulphation didn't help with other kinds of battery ills...but it's worth a try.