>I have aquired some sealed lead acid cells (plastic pack containing 6
>cells rated for 5AH) and am trying to figure out the proper charge
>current for them. I don't want to over-charge them (or under charge)
There was an article in March 1994 QST on a charger for sealed lead-acid batteries.
Key points: 1. charging voltage should not exceed 2.45 volts/cell, i.e., 14.7 volts for a 12 volt battery pack. 2. max charge rate must not exceed 15% of the amp-hour capacity
I have seen slightly different specs on the maximum permissible current in manufacturers' literature from different sources, but the maximum voltage per cell will always be the same, since this is determined by the basic chemistry of the system. I have specs from PowerSonic which specify:
Limit initial current to 20% of Ahr capacity. Charge until voltage under charge reaches 2.45 volts/cell at 68F (20C). Hold at 2.45 volts per cell until current drops to approximately 1% of Ahr capacity. At this point the battery is fully charged. It can be maintained in a fully charged condition by connecting to a constant voltage source of 2.25 to 2.30 volts per cell.
Albert S. Woodhull Hampshire College, Amherst, MA, USA awoodhull@hamp.hampshire.ed