The photo below shows the battery connection pattern for the Deka Unigy II batteries. They mount in steel racks, 3 cells across and stack upwards depending on voltage required. Shown is a 3000 lb. 24 volt, 1440 AH (over 8 hrs) system with four racks installed. Each white faced (and one black face) box is a 2.2v cell with six terminals. It's difficult to tell from the photo which sets of terminals are positive and which are negative, but the large chrome plate on the right is positive, the other is negative. Since they are connected in series, It should be fairly easy to follow the sequence of pos. & neg. on the cells.
These are lead-cadmium based absorbed mat, Valve Regulated Lead Acid (VRLA) batteries and not technically deep cycle. To keep the 20 year life expectancy, they should be floated at 2.25 volts per cell at a temperature of 77 deg. F. Variations of temperature should be compensated for and most good charge controllers are available with this feature. They should NEVER be equalized. It's also not a good idea (for longevity) to draw below 80% of full.
In the normal course of purchasing new RE equipment, Batteries of this type would not be a cost effective use of tight funds. However, there are enough telecom companies closing down operations that these sometimes become available in like new condition and relatively cheap prices.
