If you need more battery chargers, we found one at Walmart for about $25.00 that fits the FIRST requirements. We have been using three of this model and find that they work well, although now and then, one of them will show a red light when first connected, an error signal meaning that the charger didn't like the battery or the connection.
One other thing to be aware of: If you interrupt the charging cycle part way through and then restart the charger with the same battery, the charger may look at the surface charge and think that the battery is fully charged, even though the charging cycle wasn't completed. The answer is to prevent such interruptions and allow the charging process to complete until the green light comes on. (The list price of $46.25 below is from the manufacturer's web site):
For more info on this charger, see
http://www.schumacherelectric.com/itemlist.cfm?cid=2
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FIRST Team 980, The ThunderBots
2002: S. California Rookie All Stars
2004: S. California: Regional Champion,
Championship Event: Galileo 2nd seed,
IRI: Competition Winner, Cal Games: Competition Winner
2005: Arizona: 1st seed
Silicon Valley: Regional Champion (Thanks Teams 254 and 22)
S. California: Regional Runners Up (Thanks Teams 22 and 968)