more than likely they are agm type batteries, so they might be recoverable
you will need a charger that can startup charging a dead battery to start with
set it to low amperage and let it do its thing, it might take several days to get back up to something useful
if you cannot get them to accept a charge, you might carefully remove the caps and add a few cc's of distilled water heated up to about 120 degree's F,,,
once you get them charged up, put a load on them and drain them flat as a pancake, then short the posts and leave them overnight
then repeat the process, each cycle the capacity ought to increase.
once you get them to something useable, use them down to about 50% SOC and over time they will improve a bit more.
another trick is to turn the cells upside down to charge them, this will get the water to wick back up into the glass matt sometimes.
be prepared to spend several days before you see any progress, and don't add any edta or other miracle elixer, and don't use a desulfator either.... simply keep them on a charger and wait for it to get them working again.
if you add water make sure you measure it and keep it equal in all cells, start with maybe 10 cc per cell and use a syringe to distribute it as best you can across the plates in each cell. the ideas is to just get a little moistening of the mats so that charging can start to take place. after they begin to charge the interior of each cell will start to get water/acid vapor working up through the mats and over time get things working again.
all this assumes the batteries had some life left in then back when they were parked, if they were at the end of their life, it is doubtful that you will get anything out of them.
bob g
