I have 24 pieces of 900Ah/2V Deep Cycle Lead Acid batteries for connecting to a 48V - 5KW wind/solar Hybrid system. I got those off a military project, when they were still in use by them for another project, and they were given to me for use in another project.
It has been since 6 months these batteries are left unattended or not charged/discharged and haven't been even connected to a power source and load; just sitting there in a workplace waiting for the remaining components of the power system to be finished before they can be of any use.
Since now it's the time to get them connected, I was wondering if this period has caused any damage to them. They were some 2-3 years old and charged using two Morningstar 30A 24V charge controllers, when disconnected. They have been stored in an outdoor and relatively hot climate where temperatures range from 38-43 degrees during the day time.
I also noticed some blackish carbon like stuff floating in the acid, when shaken, falls apart from the top towards the bottom. Is that something falling apart e.g. the lead plates or is that something normal?
There acid is still above the 'min' indicated level.
I have included a picture for referral to the battery-type.
Any ideas on if they are still as good as when disconnected or if not, then what could be done to make them as good as when disconnected?
Thanks.